11. Fat Soluble Vitamins

8/12/2019 11. Fat Soluble Vitamins

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Fat Soluble Vitamins

Vitamins A, D, E and K


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Vitamin A and Beta-Carotene

Also known as retinol, retinal, retinoicacid

Vitamin A is found in the body incompounds known as retinoids: retinol,retinal, and retinoic acid.

These have functional roles invision, healthy epithelial cells, andgrowth.


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Vitamin A deficiency is a major healthproblem in the world.

Toxicity is often associated with abuse of

supplements. Plant foods provide carotenoids, such as

beta-carotene, some of which have vitaminA activity.

Animal foods provide compounds that areeasily converted to retinol.

Retinol binding protein (RBP) allows vitamin A

to be transported throughout the body.


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Roles in the Body

Vitamin A in Vision

Helps to maintain the cornea

Conversion of light energy into nerveimpulses at the retina

Rhodopsin is a light-sensitive pigmentof the retina that contains a proteincalled opsin.


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Roles in the Body

Vitamin A in Protein Synthesis andCell Differentiation

Through cell differentiation, vitamin A allowscells to perform specific functions.

Epithelial cells

Epithelial tissues on the outside of the

body form the skin.

Epithelial tissues on the inside of thebody form the mucous membranes.


8/60Fig. 11-4, p. 372

Vitamin A maintains

healthy cells in the

mucous membranes.

Without vitamin A, the

normal structure and

function of the cells in

the mucous membranes

are impaired.

Mucus Goblet cells

Stepped Art


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Roles in the Body

Vitamin A in Reproduction andGrowth

Sperm development in menNormal fetal development in women

Growth in children

Remodeling of the bone involves osteclasts,

osteoblasts, and lysosomes.

Osteoclasts are cells that destroy bone growth.

Osteoblasts are cells that build bones.

Lysosomes are sacs of degradative enzymes that

destroy bones.


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Roles in the Body

Beta-Carotene as an Antioxidant

Beta-carotene helps protect the body

from diseases, including cancer.


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Vitamin A Deficiency

Blindness

Xerophthalmia Xerosis is the first stage where the cornea becomes

dry and hard.

Keratomalacia is the softening of the cornea.

Keratinization Epithelial cells secrete a protein called keratinthehard, inflexible protein of hair and nails.

Changes in epithelial cells results in keratinization,rough, dry and scaly skin.

Deficiency disease is called hypovitaminosis A


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Xerophthalmia
http://images.google.com/imgres?imgurl=http://eyepathologist.com/images/KL18256.jpg&imgrefurl=http://www.eyepathologist.com/disease.asp%3FIDNUM%3D324940&h=500&w=500&sz=85&hl=en&start=10&um=1&usg=__Xe8oadsKHqW6zOsDw4c9J4LCQ7M=&tbnid=0G3Fl_UK0nIzgM:&tbnh=130&tbnw=130&prev=/images%3Fq%3DXerophthalmia%2Bpic%26um%3D1%26hl%3Den%26rls%3DRNWE,RNWE:2005-37,RNWE:en%26sa%3DX


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Vitamin A Toxicity

Can occur with concentrated amounts ofthe preformed vitamin A from animal

foods, fortified foods, or supplements. Consuming excessive amounts of beta-carotene from

supplements can be harmful.

Bone Defects

Increased activity of osteoclasts causes weakened bonesand contributes to osteoporosis and fractures.


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Vitamin A Toxicity Birth Defects

Teratogenic risk is possible, resulting in abnormalfetal development and birth defects.

Vitamin A supplements are not recommended thefirst trimester of pregnancy.

Not for Acne Massive doses for teens are not effective on acne. Accutane is made from vitamin A, but is chemically

different. It is toxic during growth and can causebirth defects.

Retin-A fights acne, the wrinkles of aging, and other

skin disorders.


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http://www.chemistryexplained.com/images/chfa_04_img0906.jpg


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Vitamin A Toxicity

Toxicity is called hypervitaminosis A

Chronic toxicity symptoms include liverabnormalities.

Acute toxicity symptoms include blurred vision,nausea, vomiting, vertigo, headaches, andpressure in the skull.

Upper level for adults: 3000 g/day


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Vitamin A Recommendations (2001 RDA)

Expressed as retinal activity equivalents(RAE) because sources include all forms ofretinoids and beta-carotene

RDA men: 900 g RAE/day

RDA women: 700 g RAE/day


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Vitamin A and Beta-Carotene Vitamin A in Foods

Retinol is found in fortified milk, cheese,cream, butter, fortified margarine, and eggs.

Beta-carotene

Spinach and other dark green leafyvegetables (chlorophyll pigment masks thecolor)

Deep orange fruits like apricots andcantaloupe

Deep orange vegetables like squash,carrots, sweet potatoes, and pumpkin

White foods are typically low in beta-carotene.

Liver is rich in vitamin A.


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Vitamin D

Vitamin D is a nonessential nutrientthat acts like a hormonein the body.

The body can make vitamin D withhelp from sunlight.

In the skin:


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Fig. 11-9, p. 377

1,25-dihydroxy vitamin

D3(active form) Stepped Art

In the liver:

Ultraviolet

light fromthe sun

In the

kidneys:

Vitamin D3

(an inactive form)

Hydroxylation

Foods

In the skin:

7-dehydrocholesterol

(a precursor made in the

liver from cholesterol)

Previtamin D3

25-hydroxy vitamin D3

Hydroxylation


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Vitamin D

Roles in the Body

Vitamin D in Bone Growth

Helps to maintain blood levels of

calcium and phosphorusWorks in combination with othernutrients and hormones

Vitamin A, vitamin C, vitamin K

Parathormone and calcitoninCollagen

Calcium, phosphorus, magnesium,and fluoride


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Vitamin D


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Vitamin D

Roles in the Body

Vitamin D in Other Roles

Immune system

Brain and nervous system

Pancreas, skin, muscles, cartilage,and reproductive organs


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Vitamin D

Vitamin D Deficiency

Factors that contribute to deficiency

Dark skin

Breastfeeding withoutsupplementation

Lack of sunlightUse of nonfortified milk


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RicketsAffects mainly children worldwide

Deficiency symptoms

Inadequate calcification of bones

Growth retardation

Misshapen bones- bowing of the legs

Enlargement of the ends of long bones

Deformities of ribs,

Lax muscles (resulting in a protrudingabdomen) and muscle spasms


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Osteomalacia

Affects adults

Soft, flexible, brittle, deformed bonesProgressive weakness

Pain in pelvis, lower back, and legs


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Osteoporosis Loss of calcium from the bones due to

inadequate synthesis of vitamin D

Results in a reduced bone density

The Elderly

Deficiency is likely due to inadequate

production and activation of vitamin D, adecreased consumption of milk, and havinglittle time in the sun.

There is an increased risk for bone loss and

fractures.


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Vitamin D

Vitamin D Recommendations (1997Adequate Intake) and Sources

AI 5 g/day for adults 19-50 years old

AI 10 g/day for adults 51-70 years old AI 15 g/day for adults if older than 70 years

of age


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Vitamin D Recommendations

Vitamin D in Foods

Fortified milk, butter, and margarine

Cereals

Chocolate mixes

Veal, beef, egg yolks, liver, fatty fishand their oils (Cod liver oil)

Vegans may need fortification orsupplements if they do not haveadequate sun exposure.


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Vitamin D Recommendations

Vitamin D from the Sun

Synthesized in the body fromcholesterol

SPF of 8 or above prevents thesynthesis of vitamin D from sunlight.

Can be obtained from tanning beds

depending on type of UV radiation.


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Rickets Belt


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Vitamin E

There are four different tocopherolcompounds, but only the alpha-tocopherolhas vitamin E activity in human beings.

Vitamin E as an Antioxidant Stops the chain reaction of free radicals

Protection of polyunsaturated fatty acidsand vitamin A

Protects the oxidation of LDLs


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Vitamin E Deficiency

Primary deficiency due to inadequateintake is rare

Erythrocyte hemolysis

Occurs in premature infants

Hemolytic anemia can be treated withvitamin E.


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Vitamin E

Vitamin E Deficiency - Symptoms Loss of muscle coordination and reflexes

Impaired vision and speech

Nerve damage

Erythrocyte hemolysis (breaking open of red blood cells)

Supplements do not prevent or cure musculardystrophy.

Fibrocystic breast disease responds to vitamin E

treatment.

Intermittent claudication responds to vitamin Etreatment.


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Vitamin E in Foods

Polyunsaturated plant oils such as margarine, saladdressings, and shortenings

Leafy green vegetables

Wheat germ

Whole grains Liver and egg yolks

Nuts and seeds

Easily destroyed by heat and oxygen


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Vitamin K

Also known as phylloquinone, menaquinone,menadione, and naphthoquinone

Vitamin K is unique in that half of human needs

are met through the action of intestinal bacteria.

Vitamin K is essential in bloodclotting.

deficiency can cause uncontrolled bleeding.

Deficiencies can occur in newborn infants and

people taking antibiotics.


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Vitamin K

Roles in the Body

Synthesis of blood-clotting proteins

Synthesis of bone proteins that regulate blood

calcium Without vitamin K, a hemorrhagic disease may

develop.

Hemophilia is a hereditary disorder and is not

cured with vitamin K.


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Vitamin K

Vitamin K Deficiency

Symptoms include hemorrhaging

Secondary deficiencies may occur with useof antibiotics.

Newborn infants receive a single dose ofvitamin K at birth because of a sterile

intestinal tract.


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Vitamin K

Vitamin K Recommendations (2001 AI)and Sources AI men: 120 g/day

AI women: 90 g/day

Vitamin K Sources Bacterial synthesis in the digestive tract

Significant Food Sources

Liver

Leafy green vegetables and cabbage-type vegetables

Milk

The Fat Soluble Vitamins In


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The Fat-Soluble Vitamins--In

Summary

The function of fat-soluble vitaminsdepends on the presence of other fat-soluble vitamins.

There are many interactions of fat-solublevitamins with minerals.

It is important to eat a wide variety offoods every day.


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Antioxidant Nutrients in

Disease Prevention

Antioxidant Nutrients in Disease


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Antioxidant Nutrients in Disease

Prevention

Oxidants are compounds in the body thatoxidize other compounds.

Antioxidants have a role in preventing

oxidation, and thus assist in theprevention of chronic disease.

Researchers and medical experts are stillclarifying the roles of these nutrients in

relationship to health and disease.


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Free Radicals and Disease

Produced by normal body processes andenvironmental factors such as ultraviolet light, airpollution and tobacco smoke

Free radicals are highly unstable due to unpaired

electrons and are often damaging.

Antioxidants stabilize free radicals and protectagainst oxidative stress.

Cognitive performance, aging, cancer, arthritis,cataracts and heart disease may be protectedwith antioxidants.


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Defending against Cancer

Antioxidants may protect DNA.

Fruits and vegetables have antioxidants

such as vitamin C and beta-carotene.


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Defending against Heart Disease

Fruits and vegetables strengthenantioxidant defenses against LDLoxidation.

Vitamin E defends against LDL oxidation,inflammations, arterial injuries and bloodclotting.

Vitamin C may protect against LDLoxidation, raises HDL, lowers totalcholesterol and improves blood pressure.


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Food, Supplements, or Both?

Food and diet

Reduce saturated or trans-fat

Select foods rich in omega-3 fatty acids.

Fruits and vegetables offer antioxidants among other

vitamins and minerals. High in whole grains and low in refined grains

Exercise, control weight and eliminate smoking toprevent disease.


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Supplements

Not enough data to confirm benefits ofsupplements only

Contents of supplements are limiting

Still need research to define optimum anddangerous levels with supplements

At high levels, supplements may act asprooxidants.


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High-antioxidant foods

Fruitspomegranates, berries and citrus

Vegetableskale, spinach and Brusselssprouts

Grainsmillet and oats

Legumespinto beans and soybeans

Nuts- walnuts

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11. Fat Soluble Vitamins