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Vitamin Glossary | Vitamin A | Vitamin D | Vitamin E | Vitamin K  | | Vitamin A | | Good to know: | Also called retinol or retinoic acid. Humans convert carotenes from plant foods into vitamin A in the body. | | Recommendations: | Men ages 11-51+, 1000 micrograms RE/day (equivalent to about 5000 IU) Women ages 11-51+, 800 micrograms RE/day (equivalent to about 4000 IU) (RE=retinol equivalent, the standard measure for vitamin A) | | Benefits: | Important for good vision, especially at night. Also affects immunity, reproduction, and the growth and maintenance of cells of the skin, gastrointestinal tract and other mucus membranes. | | Food sources: | Fortified milk, eggs, liver, cheese, leafy green vegetables (such as spinach, kale, turnip greens, collards and Romaine lettuce), broccoli, dark orange fruits and vegetables (such as apricots, carrots, pumpkin, sweet potatoes, papaya, mango and cantaloupe), red bell pepper. | | Day's supply in: | ½ cup sweet potatoes (2800 mcg), OR one carrot (2000 mcg), OR 1 oz fortified cornflakes (635 mcg) PLUS 1 cup milk (150 mcg) PLUS 1 cup raw spinach (375 mcg) | | Watch out: | Taking high-dose supplements (daily dose over 15,000 micrograms RE, or about 75,000 IU) can cause toxicity, which can result in bone fractures; joint pain; headaches; skin that is dry, itchy or peeling; brittle nails; hair loss; nausea and vomiting; diarrhea; fatigue; blurred vision; liver failure; hemorrhages. | |  | | Vitamin D | | Good to know: | The body can make vitamin D on its own, provided it gets enough sunlight. By exposing face, hands and forearms for between 5 and 30 minutes two or three times per week, most people can manufacture all the vitamin D they need. Sunscreen blocks the type of rays needed to produce vitamin D. | | Recommendations: | Ages newborn-24, 10 micrograms/day (equivalent to about 400 IU) Ages 25-50, 5 micrograms/day (equivalent to about 200 IU) Ages 51-70, 10 micrograms/day (equivalent to about 400 IU) Ages 71+, 15 micrograms/day (equivalent to about 600 IU) (IU=International Unit) | | Benefits: | Increases absorption of calcium and phosphorus, which leads to stronger bones and teeth. | | Food sources: | Fish liver oils, fatty fish, fortified milk, cheese, egg yolk, and fortified cereals. Sunlight helps the body create its own vitamin D. | | Day's supply in: | 2 cups milk (200 IU), OR 1 cup milk (100 IU) PLUS 1 cup cornflakes (40 IU) PLUS 1 egg (25 IU) PLUS 1 tsp margarine (20 IU) PLUS 3 ounces salmon with bones (10 IU) | | Watch out: | Since vitamin D is absorbed in the small intestines, people with diseases that prevent proper absorption--such as liver disease, cystic fibrosis, Whipple's disease and sprue-may develop vitamin D deficiency. Vitamin D production plateaus after a short amount of time in the sun. More exposure won't produce extra vitamin D, just skin damage. Recommended daily requirements for vitamin D are likely to increase for adults. Many experts already recommend 800 to 1,000 IU per day. Vitamin D from supplements should not exceed 50 micrograms or 2000 IU per day, unless prescribed by your doctor. | |  | | Vitamin E | | Good to know: | Also called alpha-tocopherol, tocopherol or tocotrienol. Alpha-tocopherol is the most biologically active form. | | Recommendations: | Men ages 11-51+, 10 milligrams a-TE/day (equivalent to about 30 IU) Women ages 11-51+, 8 milligrams a-TE/day (equivalent to about 24 IU) | | Benefits: | Acts as an antioxidant, reducing risks of cancer and heart disease; contributes to good immunity. | | Food sources: | Vegetable oils, wheat germ, whole-grain products, nuts, egg yolks, green leafy vegetables. | | Day's supply in: | 1 ounce wheat germ (5 mg) PLUS 1 egg (0.5 mg) PLUS 1 ounce toasted almonds (4.5 mg) | | Watch out: | The safety of very high doses of vitamin E supplements (greater than 400 mg per day) has been questioned. But there is no proof that it is harmful. | |  | | Vitamin K | | Good to know: | Also called menadione, menaquinone, or phylloquinone. Vitamin K is made in the body by normal intestinal bacteria, then absorbed for use. | | Recommendations: | Men ages 15-18, 70 micrograms/day Men ages 19-24, 70 micrograms/day Men ages 25+, 80 micrograms/day Women ages 15-18, 55 micrograms/day Women ages 19-24, 60 micrograms/day Women ages 25+, 65 micrograms/day | | Benefits: | Makes proteins that allow the blood to clot. | | Food sources: | Liver, cabbage, broccoli, green leafy vegetables (such as spinach, kale, collard and turnip greens), milk, eggs, citrus fruits. | | Day's supply in: | 1 cup raw spinach (145 mcg), OR half cup raw broccoli (60 mcg) PLUS 1 egg (25 mcg) | | Watch out: | Too much vitamin K can interfere with anti-clotting medications such as warfarin (Coumadin). | |
Last updated October 16, 2008
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