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By SUSAN ASCHOFF, Times Staff Writer
Science tells us the best source for the vitamins and minerals essential for growth and function in the human body is nutrient-rich food. Recent studies suggest such a diet may ward off diseases such as cancer and osteoporosis.
Yet an estimated 40 percent of all Americans daily pop vitamins. Why?
Many of us simply do not eat healthy food every day. The elderly and women often do not eat enough food to get needed vitamins and minerals. Teenagers' rapidly developing bodies also may need a nutritional boost.
Although the jury is out on megadosing -- taking large amounts of specific supplements in hopes of combating everything from heart attacks to thinning hair -- a quality multivitamin may compensate for some of our dietary shortcomings.
A doctor can test the blood's antioxidant and enzyme levels to determine if a person is getting adequate vitamins and minerals. Common sense goes a long way, too: A diet rich in fresh fruits and vegetables, whole grains and lean protein rather than overprocessed, high-fat foods is key to good health.
Still, most physicians agree that vitamin supplements, within reason, can help. So when confronted with shelves of vitamins that stretch the length of a store aisle -- and with what's on your plate -- here are the basics you should know.
A (retinol) -- 800 to 1000 REs (retinol equivalents).
What it does: assists in growth, prevents infection, promotes healthy hair, skin and mucous membranes and vision, particularly in dim light.
Foods: liver, egg yolks, cheese, whole milk, cod, halibut; also, beta carotene, which is found in carrots, broccoli, spinach, sweet potatoes, pumpkin, winter squash, cantaloupe, pink grapefruit and apricots.
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Beta-carotene -- not to exceed 15,000 international units (IUs).
What it does: See vitamin A.
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B-1 (thiamin) -- 1.1 to 1.5mg.
What it does: helps carbohydrates release energy, helps the functioning of heart, brain and nervous system.
Foods: whole-grain, fortified breads and cereals, dried beans and peas, and lean meats, especially pork.
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B-2 (riboflavin) -- 1.1 to 1.5mg.
What it does: transforms carbohydrates, protein and fat into energy; promotes healthy skin and the formation of red blood cells.
Foods: milk, yogurt, cheese, dark-green vegetables, meat, poultry, eggs, whole-grain and enriched breads, and cereals.
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B-3 (niacin) -- 14 to 16mg.
What it does: transforms carbohydrates, proteins and fat into energy.
Foods: dairy products, poultry, fish, lean meat, whole-grain and enriched breads, and cereals, nuts, dried beans and peas.
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B-6 (pyridoxine) -- 1.3 to 2mg (excessive amounts may cause nerve damage).
What it does: helps formation of red blood cells and neurotransmitters for brain function; helps antibodies and utilization of amino acids, proteins and fats.
Foods: liver, meat, poultry, fish, dried beans and peas, nuts, whole-grain breads and cereals, bananas.
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B-12 (cobalamin) -- 2 to 4 micrograms or mcg. (About 30 percent of seniors lose the ability to make stomach acid -- interfering with absorption of B-12, folic acid and B-6 -- so they may need larger amounts.)
What it does: helps in formation of red blood cells, building genetic material, and helps nervous system functioning.
Foods: milk, yogurt, cheese, pork, beef, shellfish, poultry, eggs, vegetable and grains.
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C (ascorbic acid) -- 60 to 100mg (smokers should take upper end of range).
What it does: forms collagen in cells, bones, cartilage, muscle and vascular tissue; maintains capillaries, bones, teeth and gums; heals wounds; aids iron absorption and protects other vitamins from oxidation.
Foods: citrus, berries, melons, dark-green vegetables, tomatoes, green peppers, cabbage, potatoes.
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D (calciferol) -- 200 IUs.
What it does: helps form and maintain bones and teeth, absorption and use of calcium and phosphorous.
Foods: egg yolks, liver, tuna, salmon, cod liver oil, fortified milk, cheese, butter, margarine and fortified cereal (also made in skin when exposed to sunlight).
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E (tocopherol) -- 30 to 60 IUs.
What it does: protects vitamin A and fatty acids from oxidation, prevents cell membrane damage.
Foods: vegetable oils and margarine, nuts, wheat germ, whole-grain breads and cereals, and green leafy vegetables.
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Folic Acid (B-9, folacin, folate) -- 400mcg.
What it does: prevents birth defects, forms hemoglobin in red blood cells, synthesis of DNA for heredity, tissue growth and cell function.
Foods: dark-green leafy vegetables, whole-grain breads and cereals, dried beans and peas, fruits, especially orange juice.
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K (phylloquinone) -- 65 to 80mcg (unless eating lots of vegetables, particularly green leafy ones).
What it does: helps control blood clotting, may help maintain bones in elderly.
Foods: green leafy vegetables, cabbage, cauliflower, cereals and soybeans (It also is made by bacteria in the intestines).
Zinc -- 12 to 15mg.
Copper -- 1.5 to 3mg.
Chromium -- 50 to 200mcg.
Iron -- 10 to 15 mg (don't overload; men and postmenopausal women may need almost no supplementation).
Possible additional supplements
Calcium -- 1000 to 1200mg (women, elderly need the most for strong bones).
Magnesium -- 320 to 420mg (can make do with 100mg typically found in multivitamins).
Phosphorous -- 500 to 700mg (usually obtained in food).
Selenium -- 55 to 75mcg (may, in high doses, reduce risk of lung, colon and prostate cancers).
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Note: Specific recommendations for each vitamin, depending on age, gender and other factors, is available online. Go to
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