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Author: Ryberg, Katie Jo Title: Intake of Vitamin D and Calcium among High School Students The accompanying research report is submitted to the University of Wisconsin-Stout, Graduate School in partial

completion of the requirements for the

Graduate Degree/ Major: MS Food and Nutritional Sciences

Research Advisor: Carol Seaborn, Ph.D.

Submission Term/Year: Summer, 2013

Number of Pages: 60

Style Manual Used: American Psychological Association, 6th edition

I understand that this research report must be officially approved by the Graduate School and that an electronic copy of the approved version will be made available through the University Library website

I attest that the research report is my original work (that any copyrightable materials have been used with the permission of the original authors), and as such, it is automatically protected by the laws, rules, and regulations of the U.S. Copyright Office.

My research advisor has approved the content and quality of this paper. STUDENT:

NAME: Katie Jo (Alters) Ryberg DATE: 6-21-2013

ADVISOR: (Committee Chair if MS Plan A or EdS Thesis or Field Project/Problem):

NAME Carol Seaborn DATE: 6-21-2013

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This section for MS Plan A Thesis or EdS Thesis/Field Project papers only Committee members (other than your advisor who is listed in the section above) 1. CMTE MEMBER’S NAME: DATE:

2. CMTE MEMBER’S NAME: DATE:

3. CMTE MEMBER’S NAME: DATE:

--------------------------------------------------------------------------------------------------------------------------------- This section to be completed by the Graduate School This final research report has been approved by the Graduate School.

Director, Office of Graduate Studies: DATE:

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Ryberg, Katie J. Intake of Vitamin D and Calcium among High School Students

Abstract

The purpose of this study was to determine if there was adequate calcium and vitamin D

consumption among 14-18 year olds prior to and after an educational discussion/activity. The

study specifically looked at calcium and vitamin D intake from a self-reported 3 day food recall,

24 hour food recall, and nutritional supplement intake of the participants. There were a total of

66 participants in the study, 22 in the control group and 44 in the experimental group. All

participants were attending high school in central Wisconsin during the time of this study. The

Food Processor SQL program was utilized to analyze the three-day food records and the 24-hour

recalls for calcium and vitamin D intake and to compare the intake to the recommended intake of

these two nutrients. Data analysis was completed using SPSS. Frequencies and percentages for

the RDA categories for vitamin D and calcium from the three day average and 24 hour recalls

were obtained as well as the mean, median, standard deviation, minimum and maximum values.

The ANOVA analyses indicated that there was a significant time by group interaction such that

over time after the instruction the experimental group achieved a greater intake of vitamin D and

calcium. However, the overall results showed the majority of participants did not achieve the

RDA for either nutrient.

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Acknowledgments

I would like to acknowledge several people that have assisted me in the preparation and

completion of this thesis. First and foremost I would like to thank Dr. Carol Seaborn, not only as

my professor teaching me tools, skills and knowledge in becoming a registered dietitian but also

for overseeing this project. Dr. Seaborn I am so grateful for all of the tireless hours you have

dedicated to me over the years not only in the classroom but also your dedication in helping

complete my thesis, I am in your debt. I would also like to thank Susan Greene in assisting with

the data analysis of this project. Her knowledge and experience were invaluable in the

completion of this project.

I would like to thank the students from the three area high schools whom participated in

this study as well as their teachers in allowing me to come and utilize their class time for this

research.

And finally, I must thank my parents who have been so supportive throughout my

education. Their mental and emotional support truly has made me the person I am today, and

they continue to push me to be a better person through that love and support. To my brother and

sister, for your never ending love and support you each have given me since childhood. You both

have smoothed the path and set the example in life for me to go forward. Josh for your

dedication and determination in your education and Erin for your strength and perseverance in

any life experience may come your way; it is incredibly humbling as your sister to thank you

both for leading those pathways for me. I love you all very much and I am proud be known as

your daughter and sister.

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Table of Contents

............................................................................................................................................. Page

Abstract ...................................................................................................................................... 2

List of Tables .............................................................................................................................. 6

List of Figures ............................................................................................................................. 7

Chapter I: Introduction ............................................................................................................... 8

Statement of the Problem ................................................................................................. 9

Purpose of the Study ...................................................................................................... 10

Definition of Terms ....................................................................................................... 10

Assumptions of the Study .............................................................................................. 13

Methodology of the Study ............................................................................................. 13

Chapter II: Literature Review .................................................................................................... 15

Calcium ......................................................................................................................... 15

Vitamin D ...................................................................................................................... 19

Nutrition Education ....................................................................................................... 26

Chapter III: Methodology .......................................................................................................... 28

Subject Selection and Description .................................................................................. 28

Instrumentation.............................................................................................................. 28

Data Collection Procedures ............................................................................................ 29

Data Analysis ................................................................................................................ 29

Limitations .................................................................................................................... 30

Chapter IV: Results ................................................................................................................... 32

Demographics .............................................................................................................. 32

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Are Adolescents Getting enough Vitamin D and Calcium through the Diet ................... 32

After Receiving Education about Vitamin D, was there an Increase in

Intake of Vitamin D ...................................................................................................... 34

After Receiving Education about Calcium, was there an Increase in

Intake of Calcium ......................................................................................................... 35

ANOVA Analysis of Vitamin D Intake between the Control and

Experimental Groups .................................................................................................... 36

ANOVA Analysis of Calcium Intake between the Control and

Experimental Groups .................................................................................................... 37

Response to Quiz Questions after the Educational Session ............................................ 39

Conclusion ................................................................................................................... 40

Chapter V: Discussion ............................................................................................................... 41

Discussion .................................................................................................................... 41

Conclusions .................................................................................................................. 45

Recommendations ........................................................................................................ 46

References ................................................................................................................................ 47

Appendix A: IRB Approval ....................................................................................................... 52

Appendix B: Consent to Participate in UW-Stout Approved Research ....................................... 53

Appendix C: Questions ............................................................................................................. 55

Appendix D: Learning Activity ................................................................................................. 58

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List of Tables Table 1: Recommended Level of Vitamin D in International Units ............................................ 22

Table 2: Pre- and Post-Intake of Vitamin D and Calcium of Control and Experimental

Groups ........................................................................................................................ 33

Table 3: Analysis of Vitamin D of Control and Experimental Group Pre- and Post-Education

by Chi-square Analysis ............................................................................................... 34

Table 4: Analysis of Calcium of Control and Experimental Group Pre- and Post-Education

by Chi-square Analysis ................................................................................................ 35

Table 5: ANOVA Analysis of Vitamin D Intake between the Control and

Experimental Groups ................................................................................................... 36

Table 6: Analysis of Calcium of Control and Experimental Group Pre- and Post-Education

by Chi-square Analysis ................................................................................................ 38

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List of Figures Figure 1: Graph showing the interaction of time with group upon vitamin D intake ................... 37

Figure 2: Graph showing the interaction of time with group upon calcium intake ..................... 39

Figure 3: Ten participants or 58% correctly identified the amount of vitamin D

needed daily ............................................................................................................. 40

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Chapter I: Introduction

Bone strength and skeletal growth is dependent upon the amounts of calcium and vitamin

D consumed by an individual, vitamin D production, and weight bearing exercises. Calcium

(absorption) contributes to bone growth and bone maintenance throughout and after skeletal

growth. One main factor that affects calcium levels in the body is vitamin D, which is important

for calcium absorption (specifically in the small intestine). Therefore to maintain adequate

skeletal bone density and perform other important physiological functions in the body, meeting

the recommended levels for calcium and vitamin D is essential. Lack of calcium consumption or

poor calcium absorption can lead to deficiencies like rickets in children and osteoporosis in the

elderly population (Higdon, 2003). Many research studies conducted within the United States

have found that high school aged adolescents do not meet the recommended dietary allowance

for calcium of 1300 mg for ages 14-18 for both girls and boys (Chang, 2005).

Vitamin D plays an important role in calcium absorption, and research has also found that

the adolescent population does not meet recommended dietary allowance, thus potentially

causing a lack of calcium absorption in the body. The lack of calcium absorption may prevent an

adolescent from achieving peak bone mass. When adequate levels of calcium intake are met and

maintained during adolescence and continued into adulthood, a decrease in the development of

osteoporosis later on in life is expected (Anderson & Auld, 1996).

Dietary habits are developed early in life. For adolescents it is important to obtain the

essential nutrients for optimal growth and development. By not consuming the proper nutrients,

adolescents are putting themselves at risk for developing deficiencies and negative side effects

associated with those deficiencies. Two important nutrients that are typically not consumed

enough in diets of teenagers are calcium and vitamin D (Sharp & Thombs, 2003). A study

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conducted by Ali (1996) found the behavioral factors effecting vitamin D and calcium absorption

included varied calcium intake, skipping meals, consumption of caffeinated beverages, weight

loss, smoking, and alcohol intake, which are all common practices amongst this population.

Adolescents who consume dairy products 2-3 times per day are more likely to meet the

RDI (recommended dietary intake) for calcium (Wallace, 2002). The RDI for vitamin D may be

met through sunlight exposure and absorption, oral intake of vitamin D-rich foods as well as

nutritional supplementation. Therefore it is important to provide nutrition education to high

school students and encourage them to participate in positive behaviors and nutritional practices

to help meet the nutrient requirements for these two nutrients and prevent deficiencies.

Statement of the Problem

Osteoporosis and osteomalacia are common diseases that plague the older generations of

the United States population, as well in other countries across the world. As an individual grows,

it is imperative to achieve peak bone mass, which can be done with adequate intakes of calcium

and vitamin D early in life. Individuals may have a difficult time achieving peak bone mass if

they lack an oral intake of calcium rich foods, lack of exposure to sunlight, and poor oral intake

of vitamin D-rich foods.

Previous research has found that adolescents across the United States do not meet the

recommended dietary intake levels of calcium and vitamin D (Looker, et al., 2011). Other

research studies conducted in a variety of countries including Lebanon, China, Canada, and

throughout Europe concluded their adolescent populations are also lacking in the consumption of

calcium and vitamin D and would benefit from increasing their intake of these nutrients. Thus it

is important to discover if adolescents living in Mid-west Wisconsin are able to meet the

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recommendations for both calcium and vitamin D with their current dietary intake, which would

be important for preventing severe bone problems later in life.

Purpose of the Study

The purpose of this study was to document the oral intake and supplement use among

teenage adolescents to discover if the adolescents are meeting the recommend dietary intake for

calcium and vitamin D. Intake will be compared with current RDA’s for both calcium and

vitamin D.

Definition of Terms

The following terms will be discussed throughout this study. For ease in reading, these

general definitions are provided here.

Adequate intake (AI). Recommended calcium intake for adolescents between the ages

from 14-18 is 1,300 mg per day, whereas the adequate intake for adults ages 19-50 is 1,000 mg

per day. An adequate intake for this mineral is necessary because calcium absorption is difficult

to estimate in the body (extracellular fluid) due to factors that affect its absorption in the small

intestine.

Bone mass. The total amount of bone tissue in the body (Bonjour, Theintz, Law,

Slosman, & Rizzoli, 1994).

Bone mineral density (BMD). The amount of mineralized bone tissue in a given area,

usually calculated in grams per square centimeter (Bonnour et al., 1994).

Calcidiol. Also known as 25-hydroxyvitamin D [25(OH)D]. This is the form generated

by the addition of a hydroxyl group at the number 25 carbon of the precursor in the liver. This

form is measured in the blood to determine vitamin D status.

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Calcitriol. The last hydroxylation at the number one position of the precursor occurs in

the kidneys. This is considered the physiologically active form of vitamin D.

Calcium. A mineral found in the human body. Specifically, 99% of calcium is found in

bones and teeth and the remaining 1% of calcium is found in blood and other soft tissues in the

body (Higdon, 2003).

Calcium deficiency. This occurs when there is not enough calcium consumed in the diet

and the body pulls calcium from the bone stores to maintain adequate levels of calcium in the

blood, thus causing bones to become weak and brittle, potentially causing fractures and leading

to osteoporosis later in life.

Calcium food sources. Calcium is primarily found in the dairy family, but good sources

are also found among green vegetables such as Bok Choy, kale, Chinese cabbage, broccoli,

spinach, rhubarb; other legume sources such as tofu and white and red beans. (Higdon, 2003).

Food frequency questionnaire (FFQ). A tool used to collect dietary intake of calcium

and vitamin D of the subject groups. The FFQ is the most common dietary assessment tool. The

FFQ asks participants to report the frequency of consumption and portion size of approximately

items containing vitamin D and calcium. In this study food records were used instead of the food

frequency questionnaire to achieve greater accuracy.

Hyperparathyroidism. A condition in which the body produces excessive amounts of

parathyroid hormone (PTH), disrupting the regulation of calcium. As a result, calcium is taken

from the bones, blood levels of calcium rise, and increased amounts of calcium may be excreted

in urine.

IU. The abbreviation for International Units, and is a label given to the amount of vitamin

D recommended by the National Institute of Health.

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NIH. The abbreviation for the National Institute for Health (NIH). The NIH is a part of

the US Department of Health and Human Services, which is the nation’s medical research

agency and responsible for making important medical discoveries that improve health and save

lives.

Osteoporosis. A skeletal disorder in which bone strength is compromised, causing higher

risk of bone fractures (Higdon, 2003). Calcium stored in the bone is extracted to achieve optimal

circulating blood levels, causing a bone to decrease in strength.

Parathyroid hormone (PTH). A hormone that regulates calcium levels. PTH prevents

the level of blood calcium from going too low by stimulating the breakdown of bone. In addition

to triggering bone loss, it can stimulate bone formation by increasing the circulating amount of

active vitamin D. Given appropriately, it can increase bone mass, and is used as a treatment for

osteoporosis.

Peak bone mass. The greatest amount of bone tissue that a person has obtained in a

lifetime; typically reached by age 30 (Bonjour, Theintz, Law, Slosman, & Rizzoli, 1994).

Physical activity of moderate intensity. Activity of 30 minutes in duration or more that

includes a cardiovascular workout, along with weight bearing exercises.

Rickets. A disorder caused by a lack of vitamin D, calcium, or phosphate. Rickets leads

to softening and weakening of the bones

RDA. The abbreviation for Recommended Dietary Allowance of vitamins and minerals.

The RDA is the average daily dietary nutrient intake level sufficient to meet the nutrient

requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and

gender group (United States Department of Agriculture, 2011).

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Vitamin D. Fat soluble vitamin that plays a key role in ensuring the absorption of

calcium from the intestines. The newest recommend levels of intake for ages 14-18 are 600 IU

daily.

Assumptions and Limitations of the Study

Assumptions were that the food frequency questionnaire was completed accurately and

truthfully. Another assumption was that the three-day food records and the 24-hour recall

reflected calcium and vitamin D intake.

Limitations to consider in conduct of the study included that the respondents may not

have answered truthfully on the food records, some incomplete food records were turned in,

under reporting or over reporting of oral intake of food could have occurred, and lack of

participation during the calcium and vitamin D education period/activity, which resulted in lack

of knowledge of food sources, non-food sources, role of sunlight in vitamin D synthesis, and

functions of calcium and vitamin D.

Methodology of the Study

The data collection was conducted in three local high schools in central Wisconsin to

discover the intake of calcium and vitamin D among the adolescent population. Data was

collected from the students via a three-day food record. All of the test subjects in the

experimental group participated in an education activity after the three-day food records were

collected. A 24-hour food record was utilized one week later to assess any changes in the

participants’ intake of both nutrients. Chapter 4 summarizes results in tables and figures, and

Chapter 5 provides significance of findings as well as suggestions for further studies.

The recommended intake levels, various functions, food sources, non-food sources, and

deficiencies will be reviewed for both calcium and vitamin D in Chapter 2. Different techniques

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used in previous research to gather data from the adolescent age group, as well as pertinent

findings are reviewed.

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Chapter II: Literature Review

Calcium and vitamin D work together in the human body to help build and maintain a

strong skeletal structure and maintain basic cellular functions. In previous research that will be

reviewed in this chapter, individuals that do not consume adequate amounts of calcium and

vitamin D are at a higher risk of developing rickets early in life and possibly osteoporosis later in

life. Chapter 2 will discuss the functions, absorption, deficiencies, recommended dietary intake

(RDA), food sources, non-food sources of calcium and Vitamin D status among the adolescent

population outside of the United States as well as within our own country. Nutrition education

will also be discussed.

Calcium

Calcium is the most common mineral in the body and has a very narrow concentration

margin (Higdon, 2003). In the body, 99% of calcium is stored within bones and teeth

(Portsmouth et al., 1994). The remaining 1% of calcium is found in soft tissues and body fluids

(Lanham-New et al., 2007). Calcium is responsible for many skeletal functions within the body.

The primary effects that calcium intake has on skeletal functions are maintaining bone mass and

preventing bone loss. Another function affected by calcium intake is obtaining skeletal peak

bone mass, which occurs primarily in early adulthood (Lesile & St. Pierre, 1999). Woo et al.

(2007) discussed the three different stages of skeletal growth. The first stage occurs during

adolescence as bone mass is acquired and peak bone mass is obtained during adolescence. The

second stage is during adulthood where the body maintains the acquired bone mass from

adolescence. Finally, the third stage of skeletal growth is observed throughout life, where bone

loss occurs as individuals get older, generally after the age of 40, or once women reach

menopause (Woo et al., 2007).

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Bone turnover occurs naturally, releasing calcium from bone to the bloodstream where it

is used for various functions. Calcium absorbed from food replaces the calcium in the

bloodstream that was lost instead of drawing calcium from bone stores (Wood, 2005). More

calcium is absorbed in the intestinal system in the presence of vitamin D, which is required for

optimal calcium absorption (Smith, 2005). With adequate amounts of vitamin D, 30-40% of

calcium is absorbed in the intestine, whereas only 10-15% of calcium will be absorbed with

inadequate levels of vitamin D. Calcium absorption in the intestine can also be reduced if there

are vitamin D absorption deficiencies, parathyroid hormone deficiencies, or if an individual has a

disorder of the intestine (Lesile & St. Pierre, 1999).

There are several factors that affect calcium absorption and achieving peak bone mass.

These factors include: genetics, lifestyle behaviors, consumption of calcium and vitamin D, and

overall eating habits. Peak bone mass can be increased through positive daily lifestyle behaviors,

even though genetics already predetermines some 60-80% of peak bone mass in an individual

(Wallace, 2002). Calcium intake will vary with each individual. Ali (1996) found the amount of

calcium available for absorption varied for different reasons. The variations included calcium

intake, skipping meals, and overall knowledge about healthy eating behaviors. The study also

found increased consumption of caffeinated beverages and weight loss affected calcium

consumption negatively (Ali, 1996). Wallace (2002) concluded other behavioral factors

associated with decreased peak bone mass aside from poor calcium intake arise from smoking

and alcohol intake.

Lack of calcium consumption or poor calcium absorption can lead to deficiencies. By not

meeting the recommended dietary intake of calcium (and vitamin D) young children may

develop rickets. Rickets is a term commonly associated with poor bone development and growth

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among children, typically caused by poor intake of vitamin D (Anderson et al., 2005). Calcium

deficiency in adults or in the elderly population is related to developing weak skeletal structure

and ultimately may lead to osteoporosis. Osteoporosis is a skeletal disorder in which bone

strength is compromised, causing a higher risk of bone fractures (Higdon, 2003). The alteration

of tissue structure can lead to fragile bones and increases the chance of bone fractures ultimately

putting individuals at a higher risk for developing osteoporosis later in life (Ford, Bass, &

Keathley, 2007). Osteoporosis is a bone disease that is caused by the deterioration of bone tissue,

along with a low bone mass density. The alteration in tissue structure can lead to fragile bones

and increases the chance of bone fractures. (Ford, Bass & Keathley, 2007). To reduce the risk of

osteoporosis, optimizing peak bone mass (PBM) in early adulthood is essential, especially since

90% of PBM is attained by the age of 18 (Bener, Al-Ali, & Hoffman, 2009).

Calcium intake has been studied for decades within and outside of the United States, with

almost all of the studies concluding the same point; calcium intake does not meet the

recommended dietary allowance for adolescents. A study conducted in the country of Lebanon

found only 16% of students participating in the study consumed the recommended adequate

intake for vitamin D (200 IU) and only 12% met the recommended dietary intake for calcium

(Salamoun et al., 2005). The daily average intake of calcium for girls and boys was 743 mg and

900 mg, respectively. The study stated that the recommended adequate intake for calcium is

1300 mg per day, and only 9.7% of girls and 15% of boys met this level. In the study, 80% of the

students achieved their daily intake of calcium from dairy products. Compared to American

boys, this study found that boys had a lower intake of calcium whereas girl’s average calcium

intake of 800 mg was similar to North American findings (Salamoun et al., 2005).

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The NIH recommends Americans to consume 1300 mg of calcium daily for ages 14-18

years old for both girls and boys (Chang, 2005). A national study, NHANES III, found the

recommended dietary intake for calcium in America is being met by only 46% of young women.

(Looker et al., 2011). In addition, 54% of young adolescent women were found to not meet the

RDA standards for overall calcium intake (Looker et al., 2011). The study also concluded

women who consume dairy products 2-3 times daily are more likely to meet the RDA

recommendation levels. These results were similar to the findings of Wallace (2002) that almost

68% of women surveyed did not meet the RDA for calcium intake and 25% of women consumed

50% or less of the recommended dietary intake.

According to Anderson and Auld (1996), reducing the development of osteoporosis later

in life could be achieved if high levels of calcium intake are maintained during adolescence and

continued into adulthood by stressing the importance of establishing good dietary habits early in

life. Anderson and colleagues in another study concluded that more focus on nutrition and

lifestyle interventions during the pubertal growth phase is important to decrease the occurrence

of osteoporosis later in life (Anderson et al., 2005). A study conducted by Chang (2005) found

that only 454 mg per day of calcium was consumed among the 30-35 year olds surveyed, which

met only 30% of the RDA. Lesile and St. Pierre (1999) found that the average daily calcium

intake in women ages 20-29 was 650 mg daily. This evidence does support that young adults

may not be getting enough calcium, a habit that originated in adolescence.

A study conducted by Portsmouth et al. (1994) found that roughly 68% of young women

around the age of 18 did not receive the Recommended Dietary Intake (RDI) for calcium in a

day. Sharp and Thombs (2003) found among adolescents aged 9-19 years old, only 19% of the

subjects consumed enough calcium to reach the recommended daily amount. In a study assessing

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calcium intake and bone density, Wallace (2002) found a strong correlation between bone

mineral density and calcium intake among the 13-19 year old subjects. As research has been

conducted over the past 10-15 years, research has been able to prove that the adolescent

population overall does not meet the RDA for calcium intake even though there are a variety of

food sources in the American diet that allow for adequate intake of calcium.

Food sources that contain calcium include milk, cheese, yogurt, tofu, vegetables such as

kale, broccoli, and Chinese cabbage, and canned sardines and salmon with soft bones (National

Institute of Health, 2009a). Individuals who consume dairy products 2-3 times per day are more

likely to meet the RDI for calcium (Wallace, 2002). If adolescents are unable to meet the RDA

for calcium from food sources, use of nutritional supplements is another way to meet the

recommended level (National Institute of Health, 2008a).

Calcium carbonate, calcium phosphate, and calcium citrate are all calcium compounds

that are found in a variety of calcium supplements. Calcium can also be found in multivitamins;

however, the consumer should refer to the labels as different multivitamins may have different

concentrations of calcium (National Institute of Health, 2009b). Woo et al. (2007) stated that

calcium supplementation during childhood and adolescence has a positive effect during skeletal

growth. In fact, a study conducted by Borer (2005) found a 1% increase in bone mineral density

with calcium supplementation of 1000 milligrams per day.

Vitamin D

As previously mentioned, calcium alone does not build and maintain strong bones.

Adequate intake of vitamin D is essential for the intestinal cells to absorb maximal calcium.

Vitamin D intake plays an important role in calcium absorption. Previous research has concluded

that the RDA’s for intake of calcium and vitamin D have not been attainable by most

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adolescents. There were new Recommended Dietary Allowances released at the end of 2010.

With the new recommendations, it is important to assess the intake of vitamin D to determine if

adolescents in the surrounding area high schools are meeting the new recommended dietary

intakes or if supplementation is needed to help meet the new RDA’s. In this section the various

functions and absorption of vitamin D, dietary and non-dietary sources, deficiency of vitamin D

and the recommended dietary intake levels will be reviewed as well as research from previous

studies of the intake of vitamin D among the adolescent population.

Vitamin D is a vitamin with multiple intracellular functions within the body. Indirectly

and directly, the active form of vitamin D controls 200 plus genes, including those responsible

for regulation of cellular proliferation, differentiation, apoptosis and angiogenesis (Holick,

2006). Importance of adequate vitamin D intake not only focuses on optimal skeletal growth, but

can also protect against type one diabetes mellitus, hypertension, multiple sclerosis and cancer

(Bener, Al-Ali, & Hoffman, 2009). Only 10-15% of dietary calcium is absorbed without the

presence of vitamin D (Bouillion, 2001). Calcidiol [25(OH)D] is the serum concentration that is

measured within the body (Gozdzik et al., 2008). Calcidiol [25(OH)D] circulating concentrations

are the best clinical indicator for overall vitamin D adequacy and are not influenced by dietary

calcium or phosphorus intake (Calvo, Baron, & Whiting, 2004). Holick (2007) stated that when

25-hydroxy vitamin D levels were increased, intestinal calcium transport increased by 45-65%,

thus reinforcing the need for adequate intake of vitamin D to help promote calcium circulation.

There are two forms of vitamin D that are absorbed within the body, vitamin D2 and

vitamin D3 (both of these terms will be referenced in this chapter as vitamin D). Vitamin D2, also

known as ergocalciferol is from plant sterol ergosterol. Vitamin D 3, known as cholecalciferol,

which is derived from mammalian cholesterol is found in abundance in fatty fishes. When an

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individual is unable to obtain enough vitamin D from sunlight, it is imperative that adequate

dietary intake is met to meet the RDA and to prevent deficiency (Ruxton & Derbyshire, 2009).

The disease associated with vitamin D deficiency in children is known as rickets

(Anderson et al., 2005). Rickets is not as common among young children in the United States

any more due to fortification (Calvo, Whiting, & Barton, 2004) of many foods. However, rickets

when encountered is caused from decreased calcium absorption, altered formation of the growth

plate, and defective mineralization of the skeleton, all resulting from inadequate intake of

vitamin D (Peters, dos Santos, Fisberg, Wood, & Martini, 2009). Other factors affecting vitamin

D plasma concentrations include skin pigmentation, age, weight, avoidance of sun exposure, use

of sunscreen, malabsorption disorders, use of certain medications, and disease/disorders of the

kidney or liver that affect vitamin D metabolism (Gozdzik et al., 2008). Thus, reduced skin

synthesis and absorption of vitamin D, inadequate dietary intake, acquired and inherited

disorders of vitamin D metabolism and responsiveness, as well as inadequate provision in breast

milk of breast fed infants are a few of the many causes of vitamin D deficiency (Bouillon, 2001).

Vitamin D deficiency not only causes the destruction of the skeleton, it also causes secondary

hyperparathyroidism (Bener, Al-Ali, & Hoffman, 2009).

The recommended amount of vitamin D is expressed in IU (international units), and the

amounts vary with each age category. Previous recommend levels of vitamin have been difficult

for some age groups to achieve. The old IU recommended level for adolescents was 200

international units (IU) per day (in Canada and the US) (Gozdzik et al., 2008). Some research

studies found that teenagers and adolescents were not able to meet the previous RDA for vitamin

D. A study conducted in Lebanon found only 16% of student participants met the RDI amount of

vitamin D (200 IU) (Salamoun et al., 2005).

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New recommendations for the daily intake of vitamin D were released in November of

2010. The new recommended levels of IU’s increase from 200 IU to 600 IU for teenagers aged

14-18 years old and adults aged 19-70 years old. Thus the RDA has tripled. Table 1 provides the

IU’s recommended for the different age groups. The upper level intake that is safe for healthy

adult consumption has increased to 4000 IU. However, continued high doses with supplements

of vitamin D may cause adverse side effects such as nausea, vomiting, confusion and heart

problems (National Institute of Health, 2008b). Holick cited Calvo, who stated that Canadian

guidelines recommend all infants and children receive 400 IU of vitamin D daily to prevent

deficiency (Holick, 2007). Regardless of guidelines, individuals should follow the

recommendations prescribed by their physicians for levels of vitamin D supplementation.

Table 1

Recommended Level of Vitamin D in International Units

Age

Recommended IU

Birth to 12 months

400

Children 1-13 years 600

Teens 14-18 600

Adults 19-70 600

Adults 71 and older 800

Pregnant & breastfeeding teens & women

600

Adequate intake of vitamin D can be obtained from oral intake and non-oral intake. The

three most common ways to obtain vitamin D are orally through dietary sources and use of

supplements and non-orally through sunlight (National Institute of Health, 2009a). With new

23

research surfacing over the past several years that Americans do not meet the RDA for vitamin

D, the government allows the fortification of some foods to increase the public’s intake of

vitamin D since most commonly consumed foods do not contain adequate amounts of vitamin D

naturally.

Food sources with higher concentrations of vitamin D include fatty fish, such as salmon,

tuna and mackerel, most of which are not commonly consumed in the region where this study

was conducted. Other food sources that contain smaller amounts of vitamin D include beef liver,

cheese, egg yolks, and mushrooms. To help increase the intake of vitamin D in foods,

fortification of foods (aside from milk, orange juice, and breakfast cereals) commonly consumed

among children and adults is essential in preventing vitamin deficiency in the future (Tangpricha

et al., 2003). Common foods fortified with vitamin D in the United States include milk, orange

juice, breakfast cereals, margarine, yogurt, and some soy beverages (National Institute of Health,

2008b).

One study found an increase of 150% of 25(OH)D serum concentration in the study

group who consumed vitamin D fortified orange juice daily versus the control group who only

saw an increase of 45% of 25(OH)D in the 12 week study (Tangpricha et al., 2003). Individuals

may be able to meet the recommended IU’s for their age group if they eat a diet with a variety of

foods that are fortified along with consumption of fatty fish. (National Institute of Health,

2008b). Adolescents do have access to fortified milk, cheeses, fortified cereals, fortified orange

juice, and eggs; and therefore, should be able to obtain some of the recommended IU’s of

vitamin D from these food sources. Whether the new RDA levels are possible to meet through

diet only is a major question.

24

A major source of vitamin D in the summer months is obtained through sunlight

exposure, along with other dietary intake of vitamin D foods as mentioned above (Salamoun et

al., 2005). Eighty to ninety percent of vitamin D absorbed in the body is obtained from sunlight

exposure and is the most reliable way for individuals to get vitamin D. Exposing hands, face,

arms, and legs to sunlight just 2-3 times a week for about 15 minutes will produce enough

vitamin D to meet theRDI (National Institute of Health, 2010).

Children and adults appear to be at a higher risk of deficiency where very few foods are

fortified with vitamin D, such as Europe and Canada, versus people who live closer to the

equator and are more exposed to sunlight. Vieth (2004) reported that people living closer to the

equator were found to have levels that met the 25-hydroxy vitamin D sufficiency due to adequate

exposure to sunlight. Unfortunately, some ethnicities such as Asians, African Americans, and

American Indians are at a higher risk for vitamin D deficiency secondary to increased cutaneous

melanin levels which interfere with production of vitamin D in the skin (Gozdzik et al., 2008).

During autumn and winter months, more UVB (sunlight) is absorbed by the ozone layer

(above the latitude of 37°) and therefore not available for vitamin D absorption in the skin

(Shakiba, Nafel, Lotfi, & Shajan, 2008). The UVB radiation that reaches the earth’s surface

during the winter months is decreased where the angle of the sun is most oblique, thus placing

individuals living within higher latitudes more at risk for vitamin D deficiency. For example at

42° north, (Boston, Massachusetts) vitamin D is not made from November through February

(Tangpricha, 2007). The participants in this study live in the Midwest (at 44° N latitude), and are

not able to obtain optimal vitamin D absorption from sunlight from November through February,

therefore making oral intake of vitamin D the only source/way to meet the RDA during these

winter months.

25

When individuals are unable to obtain adequate vitamin D through sunlight exposure and

dietary intake of vitamin D, supplements may need to be incorporated to help meet the

recommended daily intake. Most research studies look at the dietary intake of supplementation of

vitamin D and calcium as well as sunlight exposure. There is little to no research documenting

use of dietary supplementation alone of both nutrients. A study conducted in Canada found that

only 22% of the young, healthy subjects used supplements (Gozdzik et al., 2008).

People that are at a higher risk for vitamin D deficiency are those that have minimal

exposure to sunlight, for example those living in Canada and the northern half of the United

States (National Institute of Health, 2010). A study conducted in Qatar found that 57.5% of

children had no exposure to sunlight were more apt to have vitamin D deficiency (Bener, Al-Ali,

& Hoffman, 2009). It has been assumed that individuals living in sunny countries like Brazil

have adequate vitamin D levels secondary to vitamin D synthesis in the skin in response to UVB

radiation exposure. However, a Brazilian study of adolescents found the mean dietary intake of

vitamin D was 140 IU/day. Of the students that were surveyed only 14.9% met the daily

adequate intake for vitamin D (Bener, Al-Ali, & Hoffman, 2009).

One study conducted in Europe that included four Danish countries found that women

and girls have a higher intake of vitamin D compared to other countries with a high fish intake

due to vitamin D supplements (Anderson et al., 2005). Gozdzik et al. (2008) concluded their

study of healthy young adults in Toronto, Canada and found the current recommended dietary

allowance levels (200 IU) did not prevent vitamin D deficiency during winter months. Gozdzik

et al. (2008) recommended increasing the RDA levels to 1000 IU’s. According to Gozdzik et al.,

the Canadian Cancer society recommended levels upwards of 1000 IU of vitamin D daily to be

26

taken in the winter months and among individuals with vitamin D insufficiency to prevent

further deficiency of Vitamin D.

The NHANES III study conducted from 2001-2006 estimated the mean daily vitamin D

intake for adolescent girls was 180-220 IU and 270-280 IU in adolescent boys (Looker et al,

2011). Use of supplements along with sensible sun exposure and adequate dietary intake are

needed to fulfill the body’s vitamin D requirement (Holick, 2007).

Nutrition Education

Different kinds of data collection tools can be used in research of children and

adolescents. Depending on the size of the population group and type of study, there are a variety

of ways to collect data among the adolescent/teenage subject groups. Researchers have used food

frequency questionnaires, 24-hour food recalls, three-day food recalls, test-retest, or surveys to

assess knowledge level and intake of test populations.

Moore, Braid, Falk, and Klentrou stated that food frequency questionnaires are user

friendly, reliable, and efficient to work with (2007). RAM (rapid assessment method) is the type

of food frequency questionnaire that is a common tool used to assess calcium intake among

adults; however, has not been shown to be successful amongst adolescents. The 24-hour food

recall has been shown to be very popular tool used in dietary assessments within the clinical

setting (Moore et al., 2007). Moore and colleagues (2007) concluded in their study that the

RAM method was able to detect a greater amount of calcium intake among its subjects versus the

24-hour food recall method; however, the RAM method typically overestimated the intake of all

nutrients that were examined in this study versus the food recall method.

Another study conducted by Sovyanhadi and Cort used a variety of teaching methods and

styles to determine the most effective way to deliver nutrition education to a group of high

27

school students (2004). They tested four teaching methods which included role

play/video/display, grocery store tour, transparency, and power point. Overall, Sovyanhadi and

Cort (2004) concluded a combination of teaching styles and methods were needed to gain

student’s interest in nutrition education and make the students feel the relevance of the material

they were learning. Role-playing was the most statistically significant teaching method ranking

above the other methods utilized in the study. The researchers found role playing was more

highly ranked statistically due to the participants being allowed to dialogue, ask questions, and

get immediate feedback with their questions (Sovyanhadi & Cort, 2004).

Students who become educated about risk factors associated with poor calcium and

vitamin D intake and make changes in their lifestyle can decrease the likelihood of developing

osteoporosis later in life (Ford, Bass, and Keathley, 2007).

28

Chapter III: Methodology

High school students that do not consume adequate amounts of calcium and vitamin D

are at a higher risk of developing osteoporosis later in life. Thus stressing the importance to meet

the RDA’s for both calcium and vitamin D through oral intake, use of nutritional supplements or

exposure of sunlight to help prevent deficiencies of both nutrients are important with this

population. This chapter will discuss the selection of the subjects that participated in this study, a

description of the types of instrumentation used to collect data, the data collection procedures,

how the data was analyzed, and finally the limitations of the data collected.

Subject Selection and Description

The sample population for this study included adolescents aged 14-19 years old. Boys

and girls were asked to participate in the study who attended three local high schools in central

Wisconsin. Data collection was conducted in the classroom setting using 3 day food record and

24 hour food record. This research was approved by University of Wisconsin Stout IRB review

board (Appendix A).

Instrumentation

All students were given consent forms for their parent/guardian to sign to allow them to

be eligible to participate in this study (Appendix B). These consent forms were returned to the

classroom teacher who kept a record of who had returned the consent form signed. A number

was assigned by the teacher and then a numbered three-day food intake record was provided to

all eligible students.

The completed three-day food record was collected one week later. In the following

week, the experimental group participated in an education/activity period (See Appendix C for

29

the questions and Appendix D for activity) focusing on calcium and vitamin D. All participants

were then given a 24-hour food recall to complete one week later.

Data Collection Procedures

Data collection was completed in the spring of 2011. All students that participated in the

study were provided a three-day food record. Each student was responsible to fill out their oral

intake during the three days (with the assistance of their parent/guardian). The three-day food

record forms were collected one week later, and on that same day the experimental group

participated in a discussion about calcium and vitamin D. After one week, both of the study

groups were given a 24-hour food record form to complete. The control group returned the three

day food records, and did not participate in a discussion. One week later the control group was

given the 24-hour food recall to complete and then participated in the discussion about calcium

and vitamin D (same discussion as the experimental groups so that they still received the

information about calcium and vitamin D intake).

Data Analysis

Data analysis was conducted in the spring of 2013. Both the three-day food recall and 24-

hour food recalls were compiled and entered into the Food Processor SQL program. The Food

Processor SQL program was utilized to analyze the three-day food records and the 24-hour

recalls for calcium and vitamin D intake and to compare the intake to the recommended intake of

these two nutrients. Data frequencies and means were collected from the team quizzes from the

calcium and vitamin D discussion to compare the level of knowledge this age group had post-

education related to the two nutrients. Data analysis was completed using SPSS. Frequencies

and percentages for the RDA categories for vitamin D and calcium from the three-day average

and 24-hour recalls were obtained as well as the mean, median, standard deviation, minimum

30

and maximum values. Chi-square analysis (crosstabs) and the McNemar-Bowker test for

significant differences was utilized for pre- and post-counts of people in each of the RDA

categories for total calcium and total vitamin D. ANOVA was also used to determine if there

were differences in average calcium and vitamin D intake pre and post education. The ANOVA

analysis sought to answer three questions: 1) were there differences in average vitamin D intake

pre and post education (time effect)? 2) were there differences in average vitamin D intake

between the control and experimental groups (between-subjects effect)? And 3) were there

differences in average vitamin D intake pre- and post-education depending on which group the

participants were in (interaction effect-time versus group)? Statistical significance was judged

using a significance level of less than 0.05. The results will be outlined in Chapter 4.

Limitations

Using this age group of subjects posed may challenges. The students may not have

recorded the proper portions for foods eaten. Students may have not completed all three-days of

the food recall or not recorded all the daily food intakes and therefore under reported their actual

intake over the three days. For both the food records and the 24-hour recalls, the students may

have given inaccurate information to be analyzed. The test group may not have understood the

informational material presented during the education class and thus not retained the information

presented to them which would likely not affect their choices of food. A limitation of a language

barrier is quite possible as there is a strong Hmong population in central Wisconsin. The 24-hour

food recall may not provide enough information to compare to the student’s intake from the 3

day food recall intake averages. The final limitation is the food choices available in the Food

Processor Program. The best or closest alternative to food items consumed was selected by the

31

researcher. However, it cannot be assumed that every food item was exactly matched to a

corresponding item of similar nutritive content.

32

Chapter IV: Results

The purpose of this study was to determine if there was adequate calcium and vitamin D

consumption among 14-18 year olds prior to and after an educational discussion/activity. The

study specifically analyzed calcium and vitamin D intake from a self-reported three-day food

recall, 24-hour food recall, and nutritional supplement intake record of the participants. In this

chapter, the results from the oral intake from both the three-day food recall and 24-hour food

recall will be reviewed as well the responses to the survey questions to determine knowledge

obtained after the intervention.

Demographics

All of the participants were attending high school in central Wisconsin at the time of this

study. There were a total of 66 participants (31 were male and 35 were female); there were 22 in

the control group and 44 in the experimental group. The age breakdown for the eligible

participants were: three aged 14 years old, 27 aged 15 years old, 10 aged 16 years old, five aged

17 years old, 19 aged 18 years old, and one aged 19 years old. There were three students taking a

daily multivitamin or supplement identified with the three-day food recall and only two of the

adolescents documented taking a vitamin or supplement with the 24-hour food recall. The

means of calcium and vitamin D intake among the students was compared to the Recommend

Dietary Allowance (RDA’s) national levels.

Are Adolescents Getting enough Vitamin D and Calcium through the Diet?

The most important question asked by this research was “Are adolescents getting enough

vitamin D and calcium through the diet?” Table 2 shows the mean intake plus or minus standard

deviation for pre- and post-education for the two nutrients, vitamin D and calcium, for the

adolescents. The mean intake of vitamin D for the control group was 123.52 IU at pre-education

33

and post-education the mean intake was 119.14 IU; essentially no change. The minimum was

zero for both the pre- and post-vitamin D measurements and the maximum pre- and post-

measurement was 883 and 725 IU, respectively. The calcium intake for the control group pre-

education was 512 mg (median of 512, minimum of 95 and maximum of 1557) and the mean

post-calcium intake was 583 mg (median 583, minimum 157, and maximum of 1557), which

reflected no mean increase. The mean intake of vitamin D for the experimental group pre-

education was 72.37 IU and post-education was 217.07 IU, an increase of approximately 144 IU,

which was overshadowed by huge standard deviations. The maximum value for vitamin D at

pre-education was 413 and at post-education was 1240 IU. The mean calcium intake of the

experimental group at pre-education was 276 and at post-education was 826 mg, an increase of

550 mg. The minimum calcium intake pre-education was 38 and at post-education the minimum

intake was 115. The maximum calcium intake pre-education was 766 and post was 2297.

Table 2

Pre- and Post-Intake of Vitamin D and Calcium of Control and Experimental Groups

Control

n

Mean+SDa

Median

Minimum

Maximum

Pre-Vitamin D (IU) 21 123.52+186.76 72 0 883 Post-Vitamin D (IU) 22 119.14+97.5 97.5 0 725 Pre-Calcium (mg) 512.08+381.79 512.08 95 1687 Post-Calcium (mg) 583.91+308.63 583.91 157 1557 Experimental

Pre-Vitamin D (IU) 44 72.37+80.72 38.83 0 413 Post-Vitamin D (IU) 44 217.07+242.17 116.5 0 1240 Pre-Calcium (mg) 44 276.06+188.56 233.33 38 766 Post-Calcium (mg) 43 826.26+548.04 715 115 2297 a Pre-values were obtained from three-day food records and post-values were obtained from the 24-hour recalls

34

After Receiving Education about Vitamin D, was there an Increase in Intake of Vitamin D?

A second question asked by the research was whether there was an increase in vitamin D

intake after the education session. A chi-square or crosstabs analysis was conducted and the data

are presented in Table 3. Results from the three-day food recall obtained from the control group

found that 21 of the 22 participants had a vitamin D intake below the RDA level and only one

student was above the recommended level. The 24-hour food recall found 20 participants

remained below the RDA for vitamin D, one student met the RDA and one remained above RDA

for vitamin D. For the control group there was no statistically significance (p= 0.317) from the

pre-education to the post-education of the amount of intake of vitamin D; which is to be expected

for the control group. Unfortunately, using the McNemar-Bowker test, there was also no

significant difference in the experimental group pre- and post-education (p=0.083) on vitamin D.

Table 3

Analysis of Vitamin D of Control and Experimental Group Pre- and Post-Education by Chi-

square Analysis

Control Group

Post Vitamin D RDA (24-hour food record)

Below RDA

At RDA

Above RDA

Value df Sig.

Pre Vitamin D RDA (3-day food record)

21 Below RDA 21

20 0 0 1 1 0.317

0 AT RDA 1

0 1 0

1 Above RDA

0 0 1

Experimental Group

Pre Vitamin D RDA (3-day food record)

44 Below RDA

41 0 0 3 1 0.083

0 At RDA 0 0 0 0 Above

RDA 0 0 3

35

After Receiving Education about Calcium, was there an Increase in Intake of Calcium?

A third question asked was there an increase in intake of calcium? Of the 22 participants

in the control group, 20 had an intake below RDA for calcium, 1 participant had met the RDA

level, and one student exceeded the RDA (Table 4). For the 24-hour food recall, of the 22

participants, 21 of the participant’s intakes were below the RDA and only one was meeting the

recommended dietary allowance for calcium; therefore, there was no statistically significance (p

= 0.317). As the control group received the nutritional education about calcium and vitamin D

after both of the food recalls were collected, this result was anticipated. There was a significant

difference (p = 0.004) by chi-square analysis for the experimental group, which is reflected in the

two students who met the RDA and the nine students who exceeded the RDA for calcium at the

post-education time data collection versus the 44 who did not meeting the RDA at pre-education.

Table 4

Analysis of Calcium of Control and Experimental Group Pre- and Post-Education by Chi-square

Analysis

Control Group

Post Calcium RDA (24-hour food record)

Below RDA

At RDA

Above RDA

Value df Sig.

Pre Calcium RDA (3-day food record)

20 Below RDA 21

21 0 0 1 1 0.317

1 AT RDA 1

0 1 0

1 Above RDA

0 0 0

Experimental Group

Pre Calcium RDA (3-day food record)

44 Below RDA

41 0 0 3 1 0.004

0 At RDA 0 2 0 0 Above

RDA 0 0 9

36

ANOVA Analysis of Vitamin D Intake between the Control and Experimental Groups

In addition to asking the question of was there a difference in average vitamin D intake in

each group after the education (pre- versus post-education) that was addressed by chi-square

analysis, an additional question remained which was “Were there differences in average vitamin

D intake between control and experimental groups?” The differences between vitamin D intake

across the control and experimental group were tested by mixed methods ANOVA. This

analysis asked three questions: 1) were there differences in average vitamin D intake pre and

post (known as time effect)? 2) were there differences in average vitamin D intake between the

control and experimental groups (between-subjects effect)? And 3) were there differences in

average vitamin D intake pre and post (time) depending on which group the participants were in?

There was a statistically significant time effect (between the pre- versus post-education) (see

Table 5). The between-subjects effect was not significant (difference in vitamin D intake

between the control and experimental groups) likely due to the large standard deviation. There

was a statistically significant interaction effect between the control group and experimental

group.

Table 5

ANOVA Analysis of Vitamin D Intake between the Control and Experimental Groups

Group

n

Mean IU

Standard Deviation IU

Pre-vitamin D Control 21 123.52 186.76 Experimental 44 72.36 80.72

Post-vitamin D Control 21 120.05 181.45 Experimental 44 217.07 242.17

p values Time effect 0.001 Between subjects NS Interaction effect (Time versus group)

0.001

37

In a mixed function ANOVA analysis, the interaction effect takes precedence. Thus the

interaction effect of time versus group takes precedence over the time effect. Figure 1 shows the

nature of the interaction effect of time versus group. Note that the control group remained rather

parallel over time, whereas the experimental group showed a large increase in vitamin D intake

over time, which shows the interaction of group with time.

Figure 1. Graph showing the interaction of time with group upon vitamin D intake.

ANOVA Analysis of Calcium Intake between the Control and Experimental Groups.

In addition to asking the question of was there a difference in average calcium intake in

each group after the education (pre- versus post-education) that was addressed by chi-square

analysis, an additional question remained which was “Were there differences in average calcium

intake between control and experimental groups?” The differences between calcium intake

across the control and experimental group were tested by mixed methods ANOVA. This

analysis asked three questions: 1) were there differences in average calcium intake pre and post

(known as time effect)? 2) were there differences in average calcium intake between the control

38

and experimental groups (between-subjects effect)? And 3) were there differences in average

calcium intake pre and post (time) depending on which group the participants were in? There

was a statistically significant time effect (between the pre- versus post-education) (see Table 6).

The between-subjects effect was not significant (difference in calcium intake between the control

and experimental groups) likely due to the large standard deviation. There was a statistically

significant interaction effect between the control group and experimental group upon calcium

intake.

Table 6

ANOVA Analysis of Calcium Intake between the Control and Experimental Groups

Group

n

Mean mg

Standard Deviation mg

Pre-calcium

Control 22 512.08 381.79 Experimental 43 280.17 188.78

Post-calcium Control 22 583.91 308.63 Experimental 43 826.26 548.04

p values Time effect 0.001 Between subjects NS Interaction effect (Time versus group)

0.001

In a mixed function ANOVA analysis, the interaction effect takes precedence. Thus the

interaction effect of time versus group takes precedence over the time effect. Figure 2 shows the

nature of the interaction effect of time versus group. Note that the control group remained rather

parallel over time, whereas the experimental group showed a large increase in calcium intake

over time, which is showing the time versus group effect.

39

Figure 2. Graph showing the interaction of time with group upon calcium intake.

Response to Quiz Questions after the Educational Session

The last question addressed by this research was “How did the students do on the quiz

after the educational session.” The quiz was given after the instruction to a sample of the

students from the experimental group and there was no pre-test given by which to compare (see

Appendix D for questions). Some 82.4% of the students (n=17) as a result of the education

stated true to the statement “Dietary habits learned early in life (during teenage years) are more

likely to be continued into adulthood. Some 64.7% gave the correct RDA, 1300 mg, for the

adolescent’s age for question two. Question three was not analyzed as responses for correct

answer were not present in data spreadsheet. Some 88.2% choose bones and teeth as the location

of 99% of calcium found in the body. Some 76.5% correctly choose one half cup milk as having

the most calcium per serving. And 64.7% wrote in correctly “osteoporosis” as the disease

common among elderly due to a calcium deficiency, identified that calcium was absorbed in the

intestine, and correctly identified functions of calcium. Some 94.1% identified sunlight as a

source of vitamin D and 58.8% selected the four correct sources of vitamin D as mushrooms, egg

40

yolks, salmon, and tuna. Some 64.7% selected sunlight as the most absorbable source of vitamin

D. Some 76.5% of the subjects selected all of the correct responses of why vitamin D is

important, which were to help build and maintain bones and teeth and assist with calcium

absorption. And 58.8% were able to identify the two deficiency diseases of vitamin D deficiency.

Also, 58% correctly identified the amount of vitamin D needed daily, 600 IU (see Figure 3).

Figure 3. Ten participants or 58% correctly identified the amount of vitamin D needed daily.

Conclusion

Individuals may have a difficult time achieving peak bone mass if they lack oral intake of

calcium rich foods and lack of exposure to sunlight and poor oral intake of vitamin D rich foods.

This study investigated whether or not adolescents in this age group (14-18 years old) were

consuming the RDA for calcium and vitamin D for their age group. The ANOVA analyses

indicated that there was a significant time by group interaction such that over time after the

instruction the experimental group achieved a greater intake of vitamin D and calcium.

However, the majority did not achieve the RDA for either nutrient. The significance of these

findings will be discussed in Chapter 5.

41

Chapter V: Discussion

The purpose of this study was to determine if there was adequate calcium and vitamin D

consumption among 14-18 year olds prior to and after an educational discussion/activity. The

study specifically looked at calcium and vitamin D intake from a self-reported 3 day food recall,

24 hour food recall, and nutritional supplement intake of the participants. There were a total of

66 participants in the study, 22 in the control group and 44 in the experimental group. All

participants were attending high school in central Wisconsin at the time of data collection. This

chapter discusses the results, draws conclusions, and provides recommendations for future

studies. Recommendations for this age group on how to better meet their RDA needs for

calcium and Vitamin D will also be provided.

Discussion

To maintain adequate skeletal bone density and other important physiological functions

in the body, meeting the recommended levels for calcium and vitamin D is essential. Lack of

calcium consumption or poor calcium absorption can lead to deficiencies like rickets in children,

or osteoporosis in the elderly population (Higdon, 2003). Many research studies conducted

within the United States have found that high school aged adolescents do not meet the

recommended dietary allowance for calcium of 1300 mg for ages 14-18 for both girls and boys

(Chang, 2005) or 600 IU of vitamin D (Salamoun et al., 2005). Based on the results of this study

there are several items to address from the data analysis.

Adequacy of vitamin D and calcium intake by adolescents. The most important

question asked by this research was “Are adolescents getting enough vitamin D and calcium

through the diet?” The mean intake of vitamin D for the control group was 123.52 IU at pre-

education and post-education the mean intake was 119.14 IU; essentially no change. These mean

42

intakes are below the RDA level for vitamin D, which is 600 IU. Experimental group results

from the 3 day food recall found that participants’ intake was also below the RDA level for

vitamin D. Following the education discussion and question session, of the experimental group

41 students (93.2%) continued having intake below RDA for vitamin D; only three students were

above RDA level for vitamin D (6.8%).

Most of the research on intake of vitamin D has been conducted when the recommended

intake was 200 IU, one third of the amount of 600 IU presently recommended, and that research

indicates adolescents were not achieving the RDA even when the RDA was one third of the

amount of today. A study conducted in Lebanon found only 16% of the students consumed the

recommended adequate intake for vitamin D which was 200 IU at the time of the study.

Adolescents have access to vitamin D fortified milk, cheeses, fortified cereals, and eggs;

however, the question to be addressed is whether adolescents can achieve the new RDA level of

vitamin D. It appears that the adolescents studied were not able to achieve the higher RDA by

food and are at additional risk due to the fact that vitamin D is not synthesized from sunlight

from November through February due to the decrease of the sun’s radiation that strikes the

latitude where Wisconsin is located. Therefore, it seems that a recommendation for vitamin D

supplementation should be a public health pre-caution for this and other age groups.

The calcium intake for the control group pre-education was 512 mg and the mean post

calcium intake was 583 mg which reflected no mean increase. In the experimental group made

up of 44 participants, the mean intake of calcium was below the recommended dietary allowance

as shown in the 3 day food recall results. There were changes noted in the 24 hour food recall

post-education in which 33 were still below the RDA of 1300 mg (75%), two students met the

RDA (4.5%), and nine students were above the RDA (20.5%) for calcium. The mean intake of

43

calcium pre-education was 512 mg (control group) and 276 mg (experimental group) previous to

education and 583 mg (control group) and 826 mg (experimental group) after education.

Therefore, even after the education the mean intake was below the RDA.

Calcium intake has been studied for several decades with almost all of the studies

concluding the same point; calcium intake does not meet the recommended dietary allowance for

adolescents. A study conducted in Lebanon found that the daily average intake of calcium for

girls and boys was 743 mg and 900 mg, respectively, which was similar to North American

findings by Salamoun et al., 2005. NHANES III found the recommended dietary intake for

calcium in America is being met by only 46% of young women and conversely being met by

54% of young adolescent women. Portsmouth et al. (1994) found that roughly 68% of young

women around the age of 18 did not receive the RDA for calcium. Similarly, Sharp and Thombs

(2003) found among adolescents aged 9-19 years old, only 19% of the subjects consumed

enough calcium to reach the RDA. All research in the past 10-15 years, including this present

study proves that the adolescent population overall does not meet the RDA for calcium even

though there are a variety of food sources that would allow for adequate intake.

After receiving education was there an increase in intake of vitamin D and calcium?

An important question was whether the two groups’ nutritional intake of calcium and vitamin D

improved as a result of the instruction. To determine if the two groups’ intake of calcium and

vitamin D changed after instruction, the nutrient intake data pre- and post-education was

analyzed with chi-square (cross tabulation) and the McNemar-Bowker test was conducted to test

for significance. Vitamin D intake was not found to be significant as a result of the nutrition

education in the experimental group, probably due to the very large standard deviation.

However, calcium intake significantly improved in the experimental group. According to Ford,

44

Bass, and Keathley (2007) students who become educated about risk factors associated with poor

calcium and vitamin D intake and make changes in their lifestyle can decrease the likelihood of

developing osteoporosis later in life. The key to nutrition education is to select the teaching style

and method to gain student’s interest and make the students feel the relevance of the material

they are learning (Sovyanhadi & Cort, 2004).

Analysis of vitamin D intake between the control and experimental groups. In

addition to asking the question of was there a difference in average vitamin D intake in each

group after the education (pre- versus post-education) that was addressed by chi-square analysis,

an additional question remained, which was “Were there differences in average vitamin D intake

between control and experimental groups?” This question was answered by conducting a mixed

methods ANOVA. There was a statistically significant time effect (between the pre- versus post-

education) but the between-subjects effect was not significant (difference in calcium or vitamin

D intake between the control and experimental groups) likely due to the large standard deviation.

There was a statistically significant interaction effect between the control group and

experimental group upon both vitamin D and calcium intake such that the intake of both

nutrients increased over time (with the education). Therefore, it is clear that the nutrition

education did have a significant effect within the two groups on the increased intake of the two

nutrients. Although intake improved, the majority of the students did not achieve the RDA for

either nutrient.

Response to quiz questions after the educational session. The mean score for the 17

participants who took the quiz was 72%. The range of correct scores for various questions was

from 52.9% to 94.1%. Unfortunately, the test was administered to a small sample (n= 17) of the

44 students who received the education. The role of nutrition knowledge is uncertain in nutrition

45

education. The consensus is that nutrition education may play a small but pivotal role in

adoption of healthier food habits (Worsley, 2002). The knowledge-attitude-behavior model of

nutrition education proposes that as people acquire knowledge in nutrition; their attitudes change

(Contento, 2011). Changes in attitude then lead to changes in behavior. However, theories of

learning make it clear that ‘how-to’ knowledge may not impact behavior. Contento states that

“This type of knowledge may be motivating for people who are highly disciplined but for most

people this kind of knowledge is not motivational. In the nutrition education intervention studies

in which the ‘dissemination of information’ or ‘teaching of skills’ were effective, the audiences

were self-selected and already motivated” (Contento, 2011). However, motivational or why-to

knowledge can lead to changes, called outcome beliefs which were observed in the small

increase of calcium and vitamin D consumption of those who received the education. However,

the how-to knowledge tested by the quiz reflected minimal learning.

Conclusions

To increase intake of calcium rich foods as well as vitamin D rich foods or supplements

will need to be further stressed on this age group. Very few of the adolescents were taking

supplements to provide calcium and vitamin D. An educational session is a way to provide

information to this group; however, retention and usage of the discussed material by some of the

participants was not evident from the quiz scores. However, this small nutrition education effort

did show an improvement; the interaction between the group and the education was such that

intake of both calcium and vitamin D improved. Also there needs to be other methods to

encourage sun exposure or use of nutritional supplements to meet the RDA for both Vitamin D

and calcium consumption for this age group as the RDAs for both nutrients were not achieved.

46

Recommendations

Recommendations for future research. Based upon the results of this study, there are

several recommendations that future researchers may want to consider when looking at the

intake of calcium and vitamin D in this population. The researcher should strive to achieve

accurate nutrition intake records from all participating subjects. This would be focused on

teaching portion sizes. Along with providing solid nutritional facts to these students, the

researcher should utilize activities to involve the participants to increase their participation level

as well as engagement of learning the new information thus to improve the motivation to change

behavior.

Recommendations for schools. In the classroom setting there are a few

recommendations that if adopted would increase nutritional intake of calcium and vitamin D.

One recommendation is to include more nutritional education in the classroom that stresses the

importance of calcium and vitamin D intake within a balanced lifestyle, especially among this

age group. The community should foster a school policy to offer calcium-rich and vitamin D

fortified foods at school meal times and vending machines within schools. Make it a standard

practice for all teachers to encourage teenagers to spend time in the sunshine during the summer

months to absorb adequate amounts of vitamin D. If dietary intake is lacking or sun exposure is

missing, encourage families to use nutritional supplements for vitamin D and calcium especially

if adolescents are not meeting the RDA through oral intake of food alone and sun exposure. It is

clear that the majority of the adolescents in this study failed to achieve the RDA for both calcium

and vitamin D. And very few were taking supplements to achieve the RDA. Therefore,

promotion of the use of supplements would help the adolescents achieve adequate intakes.

47

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52

Appendix A: IRB Approval May 6, 2011 Dear Katie, The IRB has determined your project, "Intake of vitamin D and calcium among high schoolers” is Exempt from review by the Institutional Review Board for the Protection of Human Subjects. The project is exempt under Category 2 of the Federal Exempt Guidelines and holds for 5 years. Your project is approved from May 5, 2011, through May 4, 2016. Should you need to make modifications to your protocol or informed consent forms that do not fall within the exemption categories you will need to reapply to the IRB for review of your modified study. If your project involved administration of a survey, please copy and paste the following message to the top of your survey form before dissemination:

If you are conducting an online survey/interview, please copy and paste the following message to the top of the form: “This research has been reviewed by the UW-Stout IRB as required by the Code of Federal Regulations Title 45 Part 46.” Informed Consent: All UW-Stout faculty, staff, and students conducting human subjects research under an approved “exempt” category are still ethically bound to follow the basic ethical principles of the Belmont Report: 1) respect for persons; 2) beneficence; and 3) justice. These three principles are best reflected in the practice of obtaining informed consent from participants. If you have questions, please contact Research Services at 715-232-1126, or foxwells@uwstout.edu, and your question will be directed to the appropriate person. I wish you well in completing your study. Sincerely,

Susan Foxwell Research Administrator and Human Protections Administrator, UW-Stout Institutional Review Board for the Protection of Human Subjects in Research (IRB) Cc: Carol Seaborn

53

Appendix B: Consent to Participate in UW-Stout Approved Research

Title: Investigation of the dietary intake of high school students

Description: The Recommended Dietary Intake has recently increased. This research will investigate if high school-aged students are meeting the new recommendations for a few key nutrients. The research will also examine the intake of these nutrients after an educational program that will be presented in your classroom. The names of the nutrients are not disclosed in order to obtain an unbiased food record. Risks and Benefits: There are minimal risks for the students participating in this research. Some students may feel embarrassment admitting their dietary intake. Students will benefit from receiving nutritional information provided in the educational session. Students may use the information to improve their dietary intake of the key nutrients that will be discussed. Special Populations: If you are less than 18 years old, you must obtain a parent or guardian signature in order to participate in this research. Time Commitment and Payment: You will be asked to write down what you have eaten for 3 days to bring to class. Then you will participate in an educational session. A one-day food record will be completed before or after the educational session. Other than the educational session (55 minutes), the time commitment for participation is about 20 minutes total to record your diet intake for the four days. Confidentiality: Your name will not be included on any documents. We do not believe that you can be identified from any of this information. This informed consent will not be kept with any of the other documents completed with this project. Right to Withdraw: Your participation in this study is entirely voluntary. You may choose not to participate without any adverse consequences to you. Should you choose to participate and later wish to withdraw from the study, you may discontinue your participation at this time without incurring adverse consequences.

IRB Approval: This study has been reviewed and approved by The University of Wisconsin-Stout’s Institutional Review Board (IRB). The IRB has determined that this study meets the ethical obligations required by federal law and University policies. If you have questions or concerns or concerns regarding this study, please contact the Investigator or Advisor. If you have any questions, concerns, or reports regarding your rights as a research subject, please contact the IRB Administrator.

Investigator: Katie Alters IRB Administrator: 715-505-6268 Sue Foxwell, Director, Research Services altersk@my.uwstout.edu 152 Vocational rehabilitation Blg. UW Stout Advisor: Carol Seaborn Menomonie, WI 54751 715-232-2216 715-232-2477 seabornc@uwstout.edu foxwells@uwstout.edu

54

Statement of Consent: “By signing this consent form you (student) and your parent/guardian agree to your participation in the project entitled, “Investigation of the dietary intake of high school students.” Student signature Date Signature of Parent or guardian Date

55

Appendix C: Questions

1. True or false. Dietary habits learned early in life (during teenage years) are more likely to be continued into adulthood.

*Answer : True

2. For your age group, how much calcium (mg) should you have in one day? a) 1300 mg b) 1000 mg c) 1200 mg d) 800 mg *Answer: 1300

3. Calcium needs what vitamin to help with absorption in the body? a) Vitamin C b) Vitamin D c) Vitamin A d) Vitamin E

*Answer: B

4. 99% of Calcium is found in what part of the body? a) Skin b) Muscles c) Bones and teeth.

*Answer: C

5. Which has the most amount of calcium per serving? a) ½ cup Milk b) ½ cup Calcium fortified Orange juice. c) 6 oz. yogurt d) ½ cup vanilla ice cream.

*Answer: A- Milk has 15%. (6% per serving ice cream, 4% for yogurt)

6. What is the disease common among elderly population related to a calcium deficiency? *Answer: Osteoporosis

7. Calcium is absorbed in the …? a) Stomach b) Intestine.

*Answer: B

56

8. It’s important to consume enough Calcium because…? Pick one. a) Regulating heart beat and blood clotting b) Building and maintain healthy bones c) Stimulating hormone secretions d) Conducting nerve impulses e) All of the above f) A and B only *Answer: E

9. For your age group, how much Vitamin D (International units {IU}) should you have daily? a) 400 IU b) 600 IU c) 800 IU d) 1000 IU *Answer: 600 (ages 14-18)

10. Sunlight provides a major source of what vitamin or mineral? a) Vitamin A b) Vitamin C c) Vitamin D d) Calcium *Answer: D

11. Vitamin D may be found in which of the following 2 food sources? (Hint: There is more than one answer. a) Mushrooms and egg yolks b) Salmon and tuna c) Spinach and peanut butter d) Broccoli and salmon

*Answer: A & B

12. The most absorbable source of vitamin D is from… a) Foods we eat.

OR b) Sunlight

*Answer: B

57

13. Vitamin D is important because...? Circle one.

a) Help build and maintain strong bones b) Helps with calcium absorption in the intestine c) Helps build and maintain teeth d) Protect against type one diabetes mellitus, hypertension, multiple sclerosis and cancer. e) All of the above F) A and D only *Answer: E

14. Adequate intake of vitamin D is important to help prevent? a) Rickets b) Osteoporosis c) Vitamin C deficiency d) All of the above. e) A & B only

*Answer: E

58

Appendix 0 : Le ... rning 1\c::tivity

Who Wants some Ice Cream? --~Q)

a. For )'OUr ase &roUP. hoi<• much caldum (m&) llhoold )'OU ha\'llln on~ tby7

0 " tSOO mg b)

e) d)

::..;-:.=.. , ............ '"" f-"' ~-·f--M .. ~­~~- ,... .. ................ ... -... __

-... ·-..... -

.. .. _........ , ... ~... -U .. l~-~.-...... .... .... ,_......,~.._lu

4· 99" of C.ldwn Is (nund in wfn•l pm of tlto body?

a} Skill

b)M~c:le.s

t) Bones ll.lrd llelb.

Q,

• ')9116: ls &t<'rtd In bones&: t:cQdlw 6\Jppon. thdr slrw:tLtrr and lunc:(k>n.

• ' " ' O«dcd for muscle fund ion. oem: tnr;ram\s5ioo, IJ1trao<dlular •1&~~111ln&. bonnuot: ...cnciorur.

J)Didoryb•bic.l<urntdcurlyln li~(.trrri~l.,..,.t:el'"".-) ON nrlllv~IYI~ lmi:CIIllhr•ud .nto l!auJih(M'I

tQ -• t.rm<-.r.1n••

• l'lld. Ill~ tmpot1ant to obblo the <Sli<:JillaJ nutMnU (ur r.ptimal grvwtb aadde>-dapmatl dul\113 me ll!ltriii!Je )fOnt ofllfe.

• Good dlclal)' (healthy) llahll.ltlt.o! are PfiiCIIttd Ill dally! rc 11ft roote llkely 10 p!Y\oent de!ldeodd llbd diseaSI' s\ICh Ill! rflobctt!l, llcort ~~. Cl!ICI>I)QI'()fi•~'

s. Calef um r.ec!ds wbat \1Wllln 10 help ~1th -ablot11llon In the body?

I)VIIRMin C b)\1t..rnt• 0 c) \IUarn•n A d)VItuniD E

'0 • VIla• 11 P I• W>~~~H• lor llM ~m 1 utilli:ll[•afoilb:lu.m 1'1' the

:;. Whlcb ltaJ th.e moot am.ou111 of w id ll.lll per

a)Y.zw;iiillt ·~e._

b) 'h a.p Cllldum !crtlfled Onmpjulce. c) 6 UL )'011\111

d) 'h Wp vanillu '"" tre:un..

• Aml<tt: A- Milk has 151' (301 r~). (6!11'. loo Cl'ftUil. .q~ form1!rt ('11.5 mg))

59

• Ab"'rpdoa ol calcium~ IIB~se\ older, r~rln3 tbo need for IDilft aUdum daily.

• IAJnt tmll t:n.dtq~Ulte tuJc:ilnn int.M 1">11~ 1151mi'C'11<&. wluch le.ods lD Ootll<lpClrosu.. Ulll.matdy lru.nl>J'ios t~ rlsltol broWt boner.

II. ll'lltllpurtlllrllD catt.turne !!hOUgh Cdclum bctrlu,oc.Ofk one. _

-> !Wgulrullls heart Mal nnd blood clottinl b) Build~ a.nd mlllntaln IMAW\Y booo. e) s.i:JITillotinR bocmot'H: ll!tfdioo~ d) Cllnduc:tina nm<e impuloco c) All ohbubo~ f) A and B oorly 'Answer.£ • Tlli5 makes up tJ.e ll' of CJJ.dum funrtloM In tbt

body • O.lchlm in tllc blood •trcPm i• do$1c-ly I'I'JlUI~ted to

mnlnt"in tbr.so: prvper fanotiOIUI.

10. Sunlll!)lt pruvl.de;t~ or

Q)\'llomln A lio)VilllmlnC c)~-0 '!Ooldum

7· Caldum Is absorbed in tne ... ?

a} StolllliCb b) Intestine.

•Q r---

I•Ans•ter 8

• Culdum jj Jlltmanly ab!..ltbed In the SttWJ l!UtiStlno (wtth 1\tlp o( \'lt.omln D).

9 FCf')'UUC (InternatiOnal

• nw"' att YUY r ... fcocla thlt notu...,.....,.oln •iumla 0

·-~ ... ~nolldtoith Wlallln I> to be!p u.<tlDl

60

a} Foods l'i'O cnt. b)Sun, ht

• h Ia ftSler w Clbl&ln the Mkoquate amnunt nl •'iwnln [I from IU:II!l(lbt ftotll tood ••

• lndMclua\J """th llmmd BWI ~re nt<'IIIO inclucle JOOd ~ 0( \~tarnln I) In thdt dM « with th• ~nt....,pltmtnl.f to R'WI<I the ROI.

->llkkta b)O.U.jl011).!13 <) Vllllllllll C lldkkoey d) All ollbubow. •)AlllonJr

~ -=

J3. \lltamiD 0 as Important bee.tlJIII!._? C!J'tle ooe.

lielpbuii.J Md mainl~ror~~; bone~ HclPf l'i'itn culdwn abeorptJon In the lnttlltlne

c} Help$ oolld and mauntaln teed~ ell l'mloct ~~&tiiiSII)'PC one cllabctcs mellttus, b~, mulbplc 8C:lero!ds and w:~oer.

I e) All o£ the fllxn, () AandDonly • ADS><tr: ll

• \lit D prontotes Ca o b1orpUon, malntalr ldequt.to ttrum 01 a rod .P~~!r Ito~ for norma.liulioo

ln Rc\'kw ...

• O.laura Ulflyh:amlll () ,.:;Q .. rlb•r W mllllot~ 1111'1 ht .. lllloy INni\1 thrin.iibuut.ll •~.a~,Jr• olllli!.

• &Htloa IUO~ 110t1nxs olnlclu., "ilia \1llllllln D, and illl<qwle expoau"' to sualiJ:Iu CDn prC'I.,.nt 01lnlpeala nld .. ~eop>m~to bltr l•lllr.

• l!olahltllhiiiJ pxl. dlt~MY llthlu NOW Wp 10U 11 ... a ~1qtll' 91kl btolaltt llkl