NUTRITIONChapter 3

Test your knowledge

It is recommended that all adults consume 2 – 3 half – cup servings of fruits and vegetables every day. True or false?

FALSE. For someone consuming 2000 calories, 2 ½ cups of vegetables and 2 cups of fruit are recommended – a total of 9 half – cup servings.

Test your knowledge

Candy is the leading source of added sugars in the American Diet. True or False?

FALSE. Regular (nondiet) sodas are the leading source of added sugars and calories.

Each 12-ounce soda supplies about 10 teaspoons of sugar, or nearly 10% of the calories in a 2000 – calorie diet.

Test your knowledge

Which of the following is not a whole grain? Brown rice Wheat flour Popcorn

b. Unless labeled “whole wheat”, wheat flour is processed to remove the bran and germ and is not a whole grain.

Nutrition Requirements: Components of a healthy diet 7 essential nutrients of a healthy diet

Protein Fat (lipids) Carbohydrates Fiber Water Vitamins Minerals

Macronutrients

Micronutrients

Energy in foods is expressed in kilocalories 1 calorie = amount of heat needed to raise the

temperature of 1 liter of water 1°C.

A person needs about 2000 kilocalories a day to meet energy needs.

Kilocalories are also known as calories, but 1 calorie = 1000 kilocalories.

Of the essential nutrients, three supply with energy: Fat = 9 calories per gram Protein = 4 calories per gram Carbohydrate = 4 calories per gram. Alcohol (not essential) = 7 calories per gram.

Nutrients are released into the body through the process of digestion

Proteins

Important part of the body’s muscles and bones

Also form part of blood, enzymes, cell membranes and some hormones.

Amino acids are the basic building block of proteins

Proteins

20 amino acids are found in food

9 of them are essential: hisidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

The other 11 can be produced by the body.

Types: Complete: if they supply all the essential amino acids

Incomplete: if they do not supply all the essential amino acids.

Recommended protein intake 10 – 35% of total daily calories.

0,8 gram per kilogram of body weight 50 gr 140 pounds 65 gr 180 pounds.

Problems of an excess protein intake Excess protein is synthesized into fat A very high protein intake can strain the

kidneys and lead to dehydration

Fats

Stored in your body represent usable energy

Help to insulate the body

Provide support and cushion for organs

Help to absorb fat-soluble vitamins

Add flavor and texture to foods

Linoleic acid and alphalinoleic acid are essential to regulate blood pressure and progress of a healthy pregnancy.

Fats

Types: triglycerides

Saturated solidAnimal sourcesHydrogenation

Unsaturated liquidPlant sources

(linoleic – alpha-linoleic acids) Monounsaturated Polyunsaturated

Fats and health

Saturated fats LDL (low density lipoprotein bad

cholesterol Red meats, solid fats

Unsaturated fats HDL (high density lipoprotein) good

chlolesterol Avocados, nuts, olive and canola oil, fish

(omega 3 fatty acids)

Recommended Fat Intake

Total fats should not exceed 20 – 30 % of the total calories.

3 – 4 teaspoons of vegetable oil per day

Carbohydrates

Needed primarily to supply energy to body cells

Cells of the nervous system and blood use only energy from carbohydrates.

During intense exercise muscle cells get most of their energy from carbohydrates.

Carbohydrates

Types: Simple

One or two sugar units in each molecule Found naturally on fruits and milk Sucrose, fructose, maltose, lactose

Complex Long chains of sugar molecules Found in tubers, fruits, vegetables and

grains Starches, dietary grains

Refined carbohydrates vs. whole grains Whole grains

Consist of an inner layer of germ, a middle layer (endosperm) and an outer layer of bran. Rich in nutrients

Refined carbohydrates Germ and bran are removed leaving the starchy

endosperm. Lower in fiber, vitamins, minerals and other

beneficial compounds.

Recommended carbohydrate intake 40 – 45% of total daily calories

225 – 325 grams of carbohydrates for a 2000 calories diet.

Athletes in training should have a 60 – 70% of total daily calories.

FIBER

Non-digestible carbohydrates

Found mainly in plants

Provide bulk for feces in the large intestine, which in turn facilitate elimination.

Types of fiber

Dietary fiber: non-digestible carbohydrates and lignin found in grains, legumes and

vegetables

Functional fiber: non-digestible carbohydrates isolated from natural sources or synthesized in a lab and added to food

Total fiber: sum of dietary and functional fiber.

Soluble: slows the body’s absorption of glucose and binds cholesterol – containing compounds

Insoluble: binds water making the feces bulkier and softer so they pass easily through the intestines.

Vitamins

Organic substances

Required in small amounts to regulate processes within living cells

Humans need 13 vitamins 4 Fat soluble (A, D, E, K) 9 Water soluble (C and 8 B – complex

vitamins)

Functions of vitamins

Help chemical reactions to take place

Help unleash energy stored in carbohydrates, proteins and fats.

Production of red blood cells

Maintenance of nervous, skeletal and immune systems

Antioxidants: preserve healthy cells.

Sources of vitamins

Fruits Vegetables Grains Processed food

Flour Breakfast cereals

Skin exposed to sunlight (D) Intestinal bacteria (K)

Vitamins and disease

DEFICIENCIES Vitamin A blindness Vitamin B 6 seizures Folate babies with neural tube defect Vitamins B 6, B- 12 and folate heart

disease risk EXTRA VITAMINS

Vitamin A increase the risk of birth defects

Vitamin B-6 irreversible nerve damage

Minerals

Inorganic elements

17 essential minerals

Needed in small amounts to regulate body functions

Aid in the growth and maintenance of body tissues

Help release energy

Sources of minerals

Lean meats iron

Dairy products calcium

Whole grains and leafy vegetables magnesium

Spinach, bananas, mushrooms, white and sweet potatoes potassium

Water

The human body contains 50 – 60% of water

Medium in which most chemical reactions take place

Transports substances around the body

Lubricant

Helps to regulate body temperature

Recommended intake of water Men 3,7 liters of water

3,0 coming from beverages

Woman 2,7 liters of water 2,3 coming from

beverages

Other substances in food

Antioxidants Protects the body from the action of free

radicals and repair the damage they cause

Phytochemicals Prevent chronic diseases. Lower chlesterol levels Boost the activity of cancer – fighting immune

cells Reduce the effects of carcinogenic compounds.

Suplements Suplements might lack potentially

beneficial phytochemicals that are found only in whole foods.

Some vitamins and minerals are dangerous when ingested in excess

Might affect the absorption of other vitamins or minerals

Recommended for: Pregnant woman People over age 50 Smokers Woman with heavy menstrual flows Vegetarians (depending on their food

choices)) People with certain diseases or that take

certain medications.

Your nutritional needs can be obtained primarily from food.

NUTRITIONAL GUIDELINES:

DRIs: dietary reference intakes

Recommended intake levels for vitamins, minerals, and macronutrients

RDAs : recommended dietary allowances Focused on preventing nutritional

deficiency diseases

AI: Adequate Intake Set when there is to enough information

available to set an RDA value.

UL: Tolerable upper intake level Sets maximum daily intake by a healthy

person that is unlikely to cause health problems.

NUTRITIONAL GUIDELINES

Daily values Used as a basis for food labels Based on several sets of

guidelines Includes standards for fat,

cholesterol, carbohydrates, dietary fiber and selected vitamins and minerals.

Represent the appropriate intake levels for a 2000 calorie diet.

NUTRITIONAL GUIDELINES Dietary guidelines for Americans

Issued by the US Department of Agriculture and the Department of Health and Human Services.

Provides general guidance for choosing a healthy diet.

Its guidelines include: Nutritional recommendations Weight management recommendations Physical activity recommendations Encourages certain food groups: fruits,

vegetables, whole grains, an low fat or fat free milk products.

Recommends to reduce the use of certain substances such as sodium and alcoholic beverages.

NUTRITIONAL GUIDELINES

USDA’s My Pyramid Overall food guidance system

Developed to remind consumers to make healthy food choices and to be active everyday

1992 2005

USDA’s MY PYRAMID

Color bands represent that all food groups are needed each day for health.

Food groups are color coded: Grain group Vegetable group Fruit group Milk group Meat and bean group Oils are not considered as a food group

Differing widths of the color bands suggest about how much food should be eaten from each group.

Food group bands narrow from bottom to top suggesting to eat nutrient-dense forms of foods.

Steps and person on them symbolize that physical activity should be a part of everyday healthy living.

The slogan “Steps to a Healthier You” suggests that improvement should happen in stages, over time.Pg 80

Meeting varied needs

My Pyramid and the Dietary Guidelines for Americans provide a basis that everyone can use to create a healthy diet. However, some population groups face special dietary challenges:

Special population groups—woman, men, college students, older adults, athletes and people with special health concerns.

Food preferences—Vegetarian, lactose-intolerant, ethnic

Situations—Eating out, carrying in, cooking at home

Nutritional planning: making informed choices about food

Reading food labels

Food additives

Uses: Maintain or improve

nutritional quality Maintain freshness Help in process or preparation Alter taste or appearance

Most used: Salt Sugar Corn syrup Citric acid Baking soda Vegetable colors Mustard Pepper

Additives of potential concern:

Sulfites keep vegetables from turning brown, cause severe reactions in some people

Monosodium glutamate flavor enhancer, some people experiences episodes of sweating and increased blood pressure.

Food borne illness

Caused by pathogens found in food

Raw or undercooked animal products such as chicken, hamburger, oysters, eggs.

Drinking water, fruits

Symptoms include acute gastroenteritis, diarrhea, vomiting, fever and weakness.

Irradiated food

Food can be treated with gamma rays, X-rays or high-voltage electrons to kill potentially harmful pathogens.

Irradiation kills most pathogens, but it does not completely sterilize foods

Environmental contaminants and organic foods Certified organic goods meet strict production, processing,

handling and labeling criteria.

For plant products Must limit pesticide residues No sewage sludge

For animal products: Feed with organic products Access to outdoors No use of antibiotics or hormones No genetic engineering, ionizing, radiation.

Organic products might not be chemical free

Products with higher pesticide residues

Products with little pesticide residue

Apples, Peppers Celery Cherries Imported grapes Necttarines Peaches Pears Potatoes Red raspberries Spinach Strawberries

Asparagus Avocados Bananas Brocoli Cauliflower Corn Kiwi Mangoes Onions Papaya Pineapples Peas

Remember…

No single type of diet provides optimal health for everyone

Many cultural dietary patterns can meet people’s nutritional requirements

Customize your food plan based on your age, gender, weight, activity level, medical risk factors and personal tastes

Lab 3.3 Informed food choices

Choose three food items to evaluate.

You might want to select three similar items, such as regular, low-fat and non fat salad dressing or three very different items.

Record the information from their food labels in the table.

Lab 3.1.

List your daily menu During a regular week day During a weekend. Use apendix B to guide you Or MyPyramid.gov MyPyramid Tracker Use figure 3,7 to compare your results to the

recommendations of MyPyramid for a 2000 calories diet

Compare your results and evaluate what changes should you make to improve your diet.