1 DNT 200 NUTRITION FOR HEALTH SCIENCES VITAMINS

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DNT 200NUTRITION FOR HEALTH

SCIENCES

VITAMINS

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VITAMINS

There are no more important ingredients of a properly constituted diet than fruits and vegetables, for they contain vitamins of every class, recognized and unrecognized.

Sir Robert McCarrison1878 -1960

British Vitamin Researcher

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VITAMINSVitamins are essential, non-caloric, organic nutrients

needed in tiny amounts in the diet.• Assist enzymes in the release of energy from

carbohydrate, protein, and fat• The only disease a vitamin will cure is one caused by a

deficiency of that vitamin• May be fat soluble• May be water soluble• 1989 RDA’s coming under Dietary Reference Intakes

– Includes two sets of values that serve as goals for nutrient intake for individuals

• Recommended Dietary Allowances (RDA’s)• Adequate Intakes (AI’s)

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VITAMINS

Fat Soluble Vitamins

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VITAMINSFat Soluble Vitamins

• Vitamins A, D, E, and K• Usually occur together in the fats and oils of food• Body absorbs them from the GI tract the same way it absorbs

lipids• Any condition that interferes with fat absorption can precipitate

a deficiency of fat soluble vitamins• Once absorbed, are stored in the liver and fatty tissues until the

body needs them -- a person need not replenish them every single day

• Are not readily excreted and can build up to toxic concentrations

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Vitamin A

• Was the first to be recognized --

identified 1914

• Also known as retinol (the alcohol

form of Vitamin A), retinal (the

aldehyde form of Vitamin A, active in

the pigments of the eye), and retinoic

acid (the acid form of Vitamin A)

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Vitamin A

• Precursor is provitamin A

carotenoids, e.g. beta

carotene (found in plant

foods)

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Vitamin A

DIETARY REFERENCE INTAKE VALUE

• RDA– Males over 14 -- 900 g/day– Females over 14 -- 700g/day

• UL– 3,000 g/day (males and females)

2001 data

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Vitamin A• A years supply can be stored in the body -- 90% of it in the

liver– Deficiency possible 1-2 years after you stop eating it– Toxicity most likely when preformed Vitamin A is consumed in

excess amounts from animal-derived foods or supplements – Use caution when taking high doses of beta carotene --

supplements should be used only for prevention and control of Vitamin A deficiency

• Beta carotene stored in fat deposits as carotene (an orange pigment found in plants)

• Beta carotene may turn the skin yellow

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Vitamin AMajor Roles In The Body

• Vision– Allows the eyes to adjust to light

• Best known• Only 1/1000th of body’s Vitamin A is in the retina

• Helps maintain healthy skin and mucous membranes

• Aids in the reproductive process– Retinoic acid is a member of the family of steroid and

thyroid hormones that regulate metabolism, growth, cell differentiation, and embryonic development by directing the expression of genes

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Vitamin AMajor Roles In The Body (con’t)

• Immunity– Its maintenance of healthy epithelial tissue helps to prevent

invasion of bacteria and viruses– Appears to play a direct role in the immune system itself

• Bone and tooth growth– Participates in remodeling (the dismantling and re-

formation of bone) enabling a small bone to convert into a large bone

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Vitamin ADeficiency

• Deficiency Disease -- Hypovitaminosis A

• Symptoms– Night Blindness

• Blood bathing cells of the retina do not supply sufficient Vitamin A to rapidly regenerate visual pigments bleached by light

• Person looses the ability to recover promptly from the temporary blinding that occurs following a flash of bright light at night or simply to see after the lights go out

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Vitamin ADeficiency

Symptoms (con’t)– Blindness

• Xerophthalmia -- the progressive blindness caused by Vitamin A deficiency

• Is the major cause of childhood blindness in the world

Cornea and tissues of the eye become dry, thickened and wrinkled

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Vitamin A

Deficiency

Symptoms (con’t)– Diminished membrane integrity

• Mucous secretion in the stomach and intestine decreases hindering normal digestion and absorption of nutrients

• Infections of the respiratory tract, GI tract, urinary tract, vagina, and possibly the inner ear become likely

• Outer body surface hardens and skin becomes dry rough, and scaly

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Vitamin A

Toxicity– Toxicity Disease -- Hypervitaminosis A– Occurs when all the binding proteins for Vitamin A are

swamped and free Vitamin A attacks the cells– Is unlikely when eating a balanced diet but is a possibility

when taking large dose supplements containing the vitamin– Beta carotene is stored in fat deposits as carotene and, taken

in excess, may turn the skin yellow– Children are most susceptible to overdoses -- they need less

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Vitamin A

Vitamin A in the Diet

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Vitamin ASignificant Sources

• Retinol– Fortified Milk– Cheese– Cream– Butter– Fortified Margarine– Eggs– Liver

• Beta Carotene– Dark Leafy Greens– Deep Orange Fruits and

Vegetables

Sweet Potato: 1936 REb per 1/2 c mashedCarrots: 1915 REb per 1/2 c cookedFortified Milk: 150 REa per cupBeef Liver: 1919 REa per 3 oz friedApricots: 280 REb per 3 fresh apricotsSpinach: 737 REb per 1/2 c cookedaPreformed vitamin AbBeta-carotene

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Vitamin D• Can be synthesized by the body

from sunlight

• Also known as calciferol, cholecalciferol, and dihydroxy-vitamin D

• Precursor is the body body’s own cholesterol

• Chemical structures elucidated in 1930’s

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Vitamin D


(based on the absence of sunlight)• AI

– 5 micrograms (individuals under 51 years)– 10 micrograms (51-70 year olds)– 15 micrograms (individuals over 70 years)

• UL– 50 micrograms per day (males and females)

1998 data

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Vitamin D

Major Role In The Body

• Promotes mineralization of the bones– Helps to make calcium and phosphorus available in the

blood that bathes the bones, to be deposited as the bones harden (mineralize)

• Stimulates absorption of calcium and phosphorus from the GI tract

• Helps to withdraw them from the bones into the blood

• Stimulates their retention by the kidneys

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Vitamin D

Deficiency• Deficiency Disease

– Rickets (children)• Vitamin D deficiency disease

characterized by inadequate mineralization of bone (manifested in bowed legs or knock knees, outward bowed chest, and knobs on ribs)

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Vitamin D

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Vitamin D

Deficiency

• Deficiency Disease

– Osteomalacia (adults)

• A bone disease characterized by softening of the bones

(bending of the spine and bowing of the legs)

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Vitamin DToxicity

Toxicity Disease -- Hypervitaminosis D– Calcium absorption is increased

• High blood calcium results• Excess blood calcium tends to precipitate in the soft tissue forming stones

-- especially likely in the kidney

– During warm months of the year, when exposure to sunlight may be frequent, vitamin D supplements can harm healthy children and adults who drink two glasses of vitamin D fortified milk per day

– Sun poses no risk of toxicity• Prolonged exposure to the sun degrades the vitamin D precursor in the

skin, preventing its conversion to the active vitamin

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Vitamin D

In most of the U.S. you can’t make vitamin D from sunlight for four months of the year

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Vitamin DSignificant Sources

• Self-synthesis with the ultraviolet rays of the sunlight– Dark skinned people require longer sunlight exposure to

maximize vitamin D synthesis– Heavy clouds, smoke, or smog may filter out a good portion of

the UV waves• Fortified milk• Fortified margarine• Eggs• Liver• Small fish (sardines)• Vitamin D supplements

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Vitamin E

• Also known as tocopherol

– Alpha tocopherol -- the most

biologically active vitamin E

compound

– Tocotrienol -- less active forms of

vitamin E

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Vitamin E


• RDA– 15 milligrams from food for males & females over 14

• 22 IU’s from natural sources or• 33 IU’s from synthetic source

• UL from supplements• 1000 mg alpha tocopherol -- greater than this risks hemorrhagic

damage because it can act as an anti-coagulant2000 data

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Vitamin E


• Antioxidant (protects other compounds from being oxidized by being oxidized itself)

– Protects PUFA and vitamin A from destruction

– Especially important in the lungs, where cells are exposed

to high concentrations of oxygen and pollutants (which are

strong oxidants)

– Helps to maintain intact cell membranes

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Vitamin EDeficiency

• Deficiency Disease– Rare -- usually associated with diseases of fat malabsorption

such as cystic fibrosis (a disease of the mucous glands usually developing during childhood and causing pancreatic insufficiency and pulmonary disorders)

• Prolonged deficiency causes neuromuscular dysfunction involving the spinal cord and retina

• Classic symptom is the breaking open of red blood cells (erythrocyte hemolysis)

Toxicity• High doses may enhance anticoagulant effects of drugs

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Vitamin ESupplementation

• May be appropriate for– Premature infants -- transfer of vitamin E across

the placenta becomes maximal right before full term delivery

– Infants, children, and adults who can’t absorb fats and oils because of disease and surgery

– Individuals with certain blood disorders– Abnormal blood flow that causes cramping in the

legs (intermittent claudication)– Non-malignant breast disease (Fibrocystic breast

disease)

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Vitamin ESupplementation

• Inappropriate for– Improving athletic skill or endurance– Increasing sexual potency– “Prolonging” the life of the heart– Reversing the damage of atherosclerosis or

heart attack– Does not prevent or cure hereditary muscular

dystrophy (Nutritional muscular dystrophy is a vitamin E deficiency disease in animals)

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Vitamin ESignificant Sources

• Widespread in foods• Readily destroyed by heat

processing and oxidation• Fresh or lightly processed

foods are the most desirable sources

• Plant Oils– Margarine– Salad Dressings– Shortenings

• Green and Leafy Vegetables• Wheat Germ• Whole Grain Products• Liver• Egg Yolks• Nuts• Seeds

Corn Oil: 2.9mg per tbsp

Safflower Oil: 4.7mg per tbsp

Sunflower Seeds (shelled): 9mg per 2 tbsp

Canola Oil: 2.9mg per tbsp

Sweet Potato: 4.5mg per 1/2 cup mashed

Shrimp: 3.2mg per 3oz boiled

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Vitamin K

• Acts primarily in blood clotting• Can be synthesized by bacteria in

the intestinal tract• Recognized in 1930’s• Also known as

– Menadione (a synthetic substance)– Phylloquinone– Napthoquinone

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Vitamin K


• AI– Females over 19 -- 90 micrograms– Males over 19 -- 120 micrograms

2001 data

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Vitamin K


• Synthesis of blood clotting protein (prothrombin)– Presence can make the difference between life and

death

• Synthesis of a blood protein that regulates calcium

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Vitamin K

Deficiency

• Deficiency Disease– New babies susceptible

• Are born with a sterile digestive tract• May not be fed a good source of vitamin K at the outset• Dose of vitamin K may be given at birth to prevent hemorrhagic

disease in the newborn

– People taking sulfa drugs, which destroy intestinal bacteria may also become deficient

– Symptoms• Hemorrhaging (blood does not clot)

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Vitamin K

Deficiency• Spontaneous

hemorrhages in a chick fed vitamin K deficient diet for 15 days.

• Bottom chick was fed an adequate diet and is the same age

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Vitamin K

Toxicity

• May interfere with anti-clotting medication• Possible jaundice• Brain damage caused by vitamin K analogues

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Vitamin K

Significant Sources• Bacterial synthesis in the digestive tract• Liver• Green leafy vegetables• Cabbage-type vegetables• Milk

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VITAMINS

Water Soluble Vitamins

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VITAMINS

Water Soluble Vitamins• B-Complex Vitamins and Vitamin C• Are found in the watery compartments of foods

– All B Vitamins are natural parts of brewers yeast (not baker’s yeast) and liver

• Are distributed in the watery compartments of the body• Are easily absorbed in the bloodstream• Easily excreted if their blood concentrations are too high

– Can be toxic in large doses

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VITAMINSWater Soluble Vitamins (con’t)

• Some act as co-enzymes to the enzymes that release energy from carbohydrate, fat, and protein– Thiamin– Riboflavin– Niacin– Pantothenic Acid– Biotin

A coenzyme is a small molecule that combines with an enzyme to make it active

• One assists enzymes that metabolize amino acids– Vitamin B-6

• Some help cells to multiply– Folate– Vitamin B-12

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VITAMINSWater Soluble Vitamins

Thiamin

• Also known as vitamin B-1

• Chemical formula -- C12H17ClN4OS

• Isolated from rice polishings in 1926 by Drs. B.C.P. Jansen and W.F.Donath

• Prolonged heating of foods can destroy substantial amounts

• Leaches into water when foods are boiled or blanched

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Thiamin


• RDA– Females over 19 -- 1.1 milligrams– Males over 14 -- 1.2 milligrams– Needs are proportional to the energy expended, not

energy intake1998 data

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Thiamin

• Major role in the body– Part of PPT (thiamin pyrophosphate), a coenzyme used in

energy metabolism• Helps to release energy from fat and carbohydrate

• More is needed when energy expenditure is high

– Supports normal appetite– Supports normal nervous system function– Breaks down alcohol

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Thiamin

Deficiency• Prolonged deficiency can result in beriberi -- the thiamin

deficiency disease• Deficiency symptoms

– Edema -- Painful calf muscles– Enlarged heart -- Low morale– Abnormal heart rhythms -- Difficulty walking– Heart failure -- Loss of ankle and– Degeneration knee jerk reflexes– Wasting -- Mental confusion– Weakness -- Paralysis

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Thiamin

Significant Sources

• In all nutritious foods in moderate amounts

• Pork

• Ham

• Bacon

• Liver

• Whole Grains

• Legumes

• Nuts

Green Peas: 0.23mg per 1/2c cooked

Pork Chop: 0.87mg per 3 oz broiled chop

Black Beans: 0.21mg per 1/2c cooked

Watermelon: 0.20mg per melon wedge

Whole Wheat Bread: 0.11mg per slice

Sunflower Seeds (shelled): 0.41mg per 2 tbsp

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Riboflavin

• Also known as vitamin B-2

• Chemical formula -- C17H20N4O6

• Isolated from whey in 1933 by Dr. R. Kuhn

• Must be phosphorylated– i.e. combined with

phosphorus before it absorbed

– Both are found in milk

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Riboflavin

• Is light sensitive

– Is destroyed by ultraviolet rays of

sun or fluorescent light

– Cardboard or opaque plastic

protects it

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Riboflavin


• RDA– Females over 19 -- 1.1 milligrams– Males over 14 -- 1.3 milligrams

1998 data

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Riboflavin

• Major roles in the body– Part of FMN (flavin mononucleotide) and FAD

(flavin adenine dinucleotide), coenzymes used in energy metabolism

• Helps to release energy from carbohydrate, fat, and protein

– Supports normal vision and skin health

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RiboflavinDeficiency

• Ariboflavinosis -- the riboflavin deficiency disease• Deficiency symptoms

– Cracks and redness at the corners of the mouth– Magenta tongue (painful, smooth, purplish red tongue)– Inflamed eyelids and sensitivity to light– Reddening of cornea– Skin rash (inflammation characterized by lesions

covered with greasy scales)

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Riboflavin

Significant Sources

• Milk

• Yogurt

• Cottage Cheese

• Meat

• Leafy Green Vegetables

• Whole Grain or Enriched Breads and Cereals

Milk: 0.34mg per cup

Cottage Cheese: 0.37mg per cup

Yogurt: 0.53mg per cup

Spinach: 0.21mg per 1/2 cup cooked

Beef Liver: 3.5mg per 3oz fried

Mushrooms: 0.23mg per 1/2 cup cooked

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Niacin

• Also known as vitamin B-3, Nicotinic Acid, Nicotinamide, Niacinamide

• Chemical formula -- C6H5NO 2

• Discovered in 1867 but shown to be a vitamin in 1937 by Dr. Conrad Elvehjem

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Niacin

• Precursor is dietary tryptophan (an essential amino acid)– Body can make it from protein– Diets adequate in protein are adequate in niacin

• Is soluble in water -- therefore use the cooking liquid

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Niacin


• RDA– Females over 14 -- 14 mg/day– Males over 14 -- 16 mg/day

1998 data

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Niacin

• Major roles in the body– Part of NAD (nicotinamide adenine

dinucleotide) and NADP (its phosphate form), coenzymes used in energy metabolism

• Helps to release energy from carbohydrate, fat, and protein

– Supports health of the skin, nervous system, and digestive system

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NiacinDeficiency

• Pellagra -- the niacin deficiency disease• Deficiency symptoms -- 4 D’s

– Dermatitis– Diarrhea– Dementia– Death (if untreated)

Toxicity• Exert a drug-like effect on the nervous system, blood

lipids, and blood cholesterol• Toxicity Symptoms

– Liver Damage– Peptic Ulcers– Low Blood Pressure– Painful flush, hives, and rash (“niacin rush”)

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Niacin

Significant Sources

• Meat, Seafood, Poultry

• Whole Grain Breads and Cereal

• Legumes and Nuts

• Liver and Kidney

• All protein-containing foods

Baked Potato: 3.3mg per whole small potato

Mushrooms: 7mg per 1/2 cup cooked

Tuna (in water): 11.3mg per 3 oz

Pork Chop: 4.4mg per 3oz broiled chop

Chicken Breast: 11.7mg per 3oz cooked

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VITAMIN B-6

• Also known as Pyridoxine, Pyridoxal, and Pyridoxamine

• Synthesized 1939• Unlike other B vitamins, is

stored extensively in muscle tissue

• Alcohol actively promotes the destruction and loss of Vitamin B-6 from the body

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VITAMIN B-6


• RDA– Adults to age 50 -- 1.3 mg– Females over 50 -- 1.5 mg– Males over 50 -- 1.7 mg

1998 data

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VITAMIN B-6

• Major roles in the body– Part of PLP (pyridoxal phosphate) and PMP

(pyridoxamine phosphate), coenzymes used in amino acid and fatty acid metabolism

– Helps to convert tryptophan to niacin– Helps to make red blood cells

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Vitamin B-6Deficiency

• Deficiency disease -- has no name• Symptoms include

– Scaly dermatitis– Depression– Confusion– Convulsions– Anemia

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Vitamin B-6

Toxicity• First reported in 1983• Symptoms include

– Loss of sensation in the extremities which, after months or years, may cause irreversible nerve damage

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Vitamin B-6

Significant Sources

• Green and Leafy Vegetables

• Meats

• Fish

• Poultry

• Shellfish

• Legumes

• Fruits

• Whole Grains

Chicken Breast: 0.51mg per 3oz cooked

Navy Beans: 0.15mg per 1/2 cup cooked

Spinach: 0.22 per 1/2 cup cooked

Baked Potato: 0.70mg per whole small potato

Beef Liver: 1.2mg per 3 oz fried

Banana: 0.66mg per whole banana

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Folate

• Also known as Folic Acid, Folacin, PTA (pteroylglutamic acid)

• Chemical formula -- C19 H19 N7O6

• Found in yeast and liver in 1935

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Folate

• Need rises considerably in pregnancy and whenever cells are multiplying– Folic Acid fortification could help prevent about

half of the 2,500 spina bifida (a birth defect interfering with the development of the central nervous system) and anencephaly (congenital absence of part or all of the brain) cases per year

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Folate


• RDA– 400 micrograms DFE (males & females over 14)

• DFE’s (Dietary Folate Equivalents) account for differences in absorption

– UL -- 1,000 micrograms DFE1998 data

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Folate

• Fortification of enriched flour with 140 mcg folic acid per 100 grams flour required by FDA in January 1998

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Folate

• Functions as a part of THF (tetrahydrofolate) and DHF (dihydrofolate), coenzymes used in DNA synthesis and therefore new cell formation

• Alcohol addicted people are at risk of folate deficiency– Alcohol impairs folate absorption– Alcohol increases folate secretion– As people’s alcohol increases, folate intakes

decline• Prolonged cooking destroys most of the folate

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Folate• Has poor bioavailability -- about half of dietary

folate is available for the body– Foods deliver folate mostly in the “bound” form --

combined with a string of amino acids known as polyglutamate

– Intestines prefer the “free” form-- folate with only one glutamate attached known as monoglutamate

– Body is able to convert and store some polyglutamate– Disposal of excess folate

• Liver secretes most of it into bile• Is transported to the gall bladder• Returns to the intestine

– Complicated transport and conversion system makes folate vulnerable to GI tract disturbances

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Folate

• Folate coenzyme (tetrahydrofolate, THF and dihydrofolate, DHF) functioning requires removal of the methyl group by enlisting the help of Vitamin B-12

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Folate

Deficiency• Deficiency disease -- has no name• Impairs cell division and protein synthesis

– Red blood cell and GI tract cell replacement falters

• May be a result of– Impaired absorption– Unusual metabolic need

• Pregnancies• Cancer• Burns

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FolateDeficiency

• Is vulnerable to drug interactions– Some drugs have a chemical structure similar to folate

• Can displace the vitamin from enzymes and block metabolic pathways

– Anti-cancer drugs can cause deficiency– Aspirin and antacids may interfere with the body’s

handling of folate– Irritability– Insomnia

Toxicity• May mask Vitamin B-12 deficiency symptoms

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Folate

Significant Sources• Leafy Green

Vegetables• Legumes• Seeds• Liver

Liver: 187 mcg per 3 oz fried

Asparagus: 131 mcg per 1/2 cup

Spinach: 108 mcg per 1 cup raw

Pinto Beans: 147 mcg per 1/2 cup cooked

Beets: 45 mcg per 1/2 cup cooked

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Vitamin B-12

• Also known as

cobalamin

• Chemical formula --

C63H90CoN14O14P

• Isolated from liver in

1948

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Vitamin B-12• Functions

– Activates the folate coenzyme

– Part of methylcobalamin and deoxyadenosylcobalamin, the active forms of coenzyme B-12, coenzymes used in new cell synthesis

– Maintains the sheath that surrounds and protects nerve fibers and promotes their normal growth

– Helps to break down fatty acids and amino acids

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Vitamin B-12


• RDA– Males & females over 14 -- 2.4 micrograms

1998 data

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Vitamin B-12

• Is unique among nutrients in being found almost exclusively in animal flesh and animal products– Vitamin B-12 in plant products occurs in an

inactive and unavailable form. After ingestion, requires intrinsic factor for absorption

– Intrinsic factor is a glycoprotein (a protein with short polysaccharide chains attached) made in the stomach that aids in the absorption of Vitamin B-12

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Vitamin B-12

• Most Vitamin B-12 deficiencies reflect inadequate absorption, not inadequate intake

• Pernicious anemia is a blood disorder that reflects a Vitamin B-12 deficiency caused by lack of intrinsic factor When consumption of Vitamin B-12 stops, deficiencies may take almost 20 years to develop

• The body recycles much of the vitamin, reabsorbing• Even when the body fails to absorb Vitamin B-12, deficiency

may take up to 3 years because the body conserves its supply

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Vitamin B-12

Deficiency• Deficiency disease -- pernicious anemia (B-

12 deficiency caused by lack of intrinsic factor, not that caused by inadequate intake)

• Characterized by– Macrocytic anemia (the anemia of folate

deficiency)• Large immature red blood cells indicative of

– Slow DNA synthesis– An inability to divide

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• Either Vitamin B-12 or Folate will clear up the anemia, however

– If Folate is given when B-12 is needed, devastating neurological symptoms result since

» B-12, not folate maintains the sheath that surrounds and protects nerve fibers and promotes their normal growth

– Folate “cures” the blood symptoms of Vitamin B-12 deficiency but allows the nerve symptoms to progress

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• Creeping paralysis beginning at the extremities and working up the spine

• Neurological symptoms can occur in the absence of anemia

• Early detection necessary to prevent permanent nerve damage and paralysis

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Vitamin B-12

Significant Sources• Animal products

– Meat

– Fish

– Poultry

– Shellfish

– Milk

– Cheese

– Eggs

Cottage Cheese: 1.3mcg per cup

Sirloin Steak: 2.4mcg per 3 oz steak cooked

Chicken Liver: 16.5mcg per 3 oz cooked

Tuna (in water): 1.8mcg per 3 oz

Sardines: 7.6 mcg per 3 oz

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Pantothenic Acid

• Is the most commonly occurring of all the vitamins -- name means “everywhere”

• Chemical formula C9H17O5N

• Isolated from rice husks in 1939 by Dr. R.J. Williams

• Is readily destroyed by heat -- losses during food preparation can be substantial

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Pantothenic Acid

• Functions– Part of Coenzyme A (Acetyl coenzyme A is the

“crossroads” compound in several metabolic pathways including the TCA cycle)

– Aids in the formation of cholesterol, hemoglobin, and other hormones

– Assists in synthesizing certain fatty acids

– Helps to break down fatty acids and amino acids

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Pantothenic Acid


• AI– 5.0 micrograms for males & females over 14

1998 data

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Pantothenic Acid

Deficiency• Rare -- involves a general failure of all the body’s

systems• Symptoms

– Vomiting– Intestinal distress– Insomnia– Fatigue

Toxicity• Symptoms

– Occasional diarrhea– Water retention (rare)

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Biotin

• Is widespread in foods

• Isolated 1936

• Chemical formula -- C10H16O3N2S

• Is synthesized by GI tract bacteria

• In foods, appears to be resistant to heat and light

91


Biotin

• Functions

– Plays an important role in metabolism as a coenzyme that

serves as a carbon dioxide carrier

– Serves crucial roles in

• Gluconeogenisis

• Fatty acid synthesis

• Breakdown of certain fatty acids and amino acids

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Biotin


• AI-- 30 micrograms (males & females over 19)1998 data

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Biotin

Deficiency

• Rare• Can be induced by avidin (a protein found in raw

eggs)– More than two dozen raw egg whites must be

ingested to bind biotin and thus prevent its absorption

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BiotinDeficiency

• Symptoms– Abnormal heart action– Loss of appetite– Nausea– Depression– Muscle pain– Weakness– Fatigue– Dry skin– Scaly dermatitis– Loss of hair

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Vitamin C

• Also known as ascorbic acid• Isolated 1928• Chemical formula -- C6H8O6

• Intakes of at least 10mg per day will prevent the appearance of the symptoms of scurvy

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Vitamin C


• RDA– Men over 19 -- 90mg– Women over 19 -- 75mg– Smokers

• Add 35mg• More likely to suffer from biological processes that damage the cells and

deplete Vitamin C• UL

– 2000mg (may cause diarrhea)2000 data

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Vitamin C• Functions

– Antioxidant• An antioxidant is a compound that protects others from oxidation by being

oxidized itself• Protects cells from oxidation

– Donates electrons to (reduces) other substances and simultaneously becomes oxidized itself

• Manufacturers sometimes add Vitamin C to protect important constituents in them

– Protects other molecules» Cells» Body fluids

– Protects iron and promotes its absorption» Intestines

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Vitamin C

• Functions (continued)– Collagen synthesis

• Vitamin C helps to form the fibrous structural protein collagen -- requires iron

• Collagen serves as the matrix on which the bones and teeth are formed

• Following wounds, collagen glues the separated tissue faces together, forming scars

• Cells are held together largely by collagen

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Vitamin C

• Functions (continued)– Assists in amino acid metabolism

• Some of these may end up being converted to hormones

– Epinephrine -- modulates the stress response

– Thyroxin -- regulates the body’s metabolic rate

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Vitamin C

• Functions (continued)

– Helps in the absorption of iron

• Enhances non-heme (from sources other than

meat, poultry and fish) iron absorption from foods

eaten in the same meal

101


Vitamin C• Recommendations

– 10mg per day scurvy symptoms are prevented but not all body tissues are saturated

– 100mg per day results in 95% of population reaching tissue saturation

– After tissues are saturated, all added vitamin C is excreted– Physical stresses deplete the body pool and may make

intakes in excess of the DRI desirable

102


Vitamin C

Deficiency

• Early signs– Blood vessel integrity degradation

• Gums around the teeth bleed easily• Capillaries under the skin break spontaneously

producing pinpoint hemorrhages• Atherosclerotic plaques grow rapidly in the arteries• Microcytic (small cell type) anemia

***** 103


Vitamin CDeficiency

• Scurvy– Symptoms begin to appear when the body’s Vitamin

C pool falls to about 20% of its optimal size (may take several weeks on a diet lacking Vitamin C)

• Further hemorrhaging due to diminishing collagen synthesis

Gingival Hemorrhaging Periungal Hemorrhaging

**** 104


Vitamin CDeficiency

• Scurvy - Symptoms con’t• Muscle degeneration (including heart)• Skin becomes rough, scaly, and dry• Wounds fail to heal because scar tissue fails to form• Bone re-building falters

– Ends of long bones become softened, malformed, and painful– Fractures appear

• Teeth become loose as cartilage around them weakens• Hysteria• Depression• Sudden death likely

– Severe atherosclerosis– Massive bleeding into joints and body cavities

– Moderate doses of Vitamin C (100mg per day) will readily reverse scurvy

*** 105


Vitamin CToxicity

• Nausea• Abdominal cramps• Diarrhea• Interference with medical regimes

– Large amounts of Vitamin C excreted in the urine may obscure the results of tests

– May diminish the effect of anti-clotting medications• Kidney stone formation in persons:

– With a tendency toward gout– With genetic abnormalities that alter the way Vitamin C breaks down to

its excretion products

** 106


Vitamin C

Toxicity• Rebound scurvy

– Persons who have taken large doses for a long time may adapt by limiting absorption and destroying and excreting more of the vitamin than usual

– When intake suddenly returns to normal, the accelerated disposal system is unable to adapt

* 107


Vitamin C

Vitamin C in the Diet

108


Vitamin CSignificant Sources

• Citrus fruits

• Cabbage-type vegetables

• Dark green vegetables

• Cantaloupe

• Strawberries

• Peppers

• Lettuce

• Tomatoes

• Potatoes

• Papayas

• Mangoes

Broccoli: 58 mg per 1/2 c cooked

Sweet Red Pepper: 95 mg per 1/2 c chopped fresh

Strawberries: 42 mg per 1/2 c fresh

Grapefruit: 47 mg per 1/2 grapefruit

Orange Juice: 93 mg per 3/4 cup

Brussels Sprouts: 48 mg per 1/2 cup cooked

Green Pepper: 45 mg per 1/2 cup chopped fresh

Documents

1 DNT 200 NUTRITION FOR HEALTH SCIENCES VITAMINS