vitamins

Vitamins

11. Vitamin D
  • Regulates calcium and phosphorus levels and promotes absorption of these minerals for growth of bones and teeth; involved in insulin secretion; supports immune function; regulates blood pressure.
  • Vitamin D can be produced in the skin upon exposure to sunlight or must be obtained from the diet.
  • Used to prevent and treat osteoporosis, psoriasis, autoimmune disease, and to reduce the risk of cancer.
  • Deficiency occurs with inadequate dietary intake, limited sun exposure, kidney or liver disease, and alcoholism. Elderly, dark-skinned, obese people, or those with inflammatory bowel disease and fat-malabsorption syndromes (celiac disease and cystic fi brosis) are also at greater risk.
  • Deficiency causes rickets (weak, deformed bones) in children, osteomalacia (soft bones) and osteoporosis in adults, dental problems, muscle weakness, and tooth decay.
  • Drugs that deplete vitamin D: carbamazepine, phenytoin, phenobarbital, cimetidine, ranitidine, cholestyramine, colestipol, orlistat, and mineral oil.
  • Since vitamin D is found in few foods and at low amounts, a supplement is recommended for most people. Most multivitamins provide 400 IU (10 mcg). Those with limited sun exposure, osteoporosis, multiple sclerosis, psoriasis, and those over age 65 should consider additional vitamin D.

  • Food Sources : Fatty fi sh (mackerel, salmon, sardines), fi sh liver oils, eggs from hens fed vitamin D, and milk
  • Adequate Intake : (mcg/day)*
    Men and
    Women 19–50 years = 5 50–70 = 10 71+ = 15
    Pregnancy = 5
    Lactation = 5
  • Upper Limit : (mcg/day)
    Men = 50
    Women = 50
    Pregnancy = 50
    Lactation = 50
    Note: 1 mcg = 40 IU
  • Side Effects : Hypercalcemia (calcium deposits in kidneys, arteries, heart, ears, and lungs, and bone loss); symptoms include headache, weakness, nausea, vomiting, constipation
    • 12. Vitamin E
  • Is an antioxidant (protects cell membranes against oxidative damage; prevents LDL oxidation) that supports immune function, prevents blood clotting, and dilates blood vessels.
  • Used to prevent and treat heart disease, cancer, macular degeneration, and cataracts, enhance immune response, reduce oxidative stress, and improve cognitive function.
  • Deficiency is rare, except in those who are malnourished or who have fat-malabsorption conditions (celiac disease, cystic fibrosis); however, suboptimal intake is common and associated with increased risk of heart disease.
  • Symptoms of deficiency include impaired balance and coordination, damage to sensory nerves (peripheral neuropathy), muscle weakness (myopathy), and damage to the retina of the eye (pigmented retinopathy).
  • Drugs that deplete vitamin E: cholestyramine, colestipol, isoniazid, mineral oil, orlistat, sucralfate, phenobarbitol, phenytoin, and carbamazepine.
  • Vitamin E may enhance the blood-thinning effects of warfarin.
  • It is difficult to achieve the RDA from diet alone; supplements are particularly necessary to achieve amounts needed for disease prevention.
  • Look for natural vitamin E (alpha-tocopherol); the synthetic form (dl-alphatocopherol) is less bioavailable (i.e., less absorbable) and only half as potent.

  • Food Sources : Vegetable oils (olive, sunfl ower, saffl ower oils), nuts, whole grains, and green leafy vegetables
  • Adequate Intake : (mg/day)
    Men = 15
    Women = 15
    Pregnancy = 15
    Lactation = 19
  • Upper Limit : (mg/day)
    Men = 1,000
    Women = 1,000
    Pregnancy = 1,000
    Lactation = 1,000
    Note: 1 mg alphatocopherol 1.5 IU
  • Side Effects : No adverse effects from vitamin Econtaining foods; supplements may increase the risk of bleeding in some individuals, particularly those taking bloodthinning drugs
    • 13. Vitamin K
  • Essential for blood clotting; required for bone formation and cell growth.
  • Useful in the prevention of osteoporosis.
  • Deficiency is rare in adults and causes impaired blood clotting; it is more common in newborns and can cause severe bleeding. Injections of vitamin K1 are typically given to newborns.
  • Symptoms of deficiency include easy bruising and bleeding (nosebleeds, bleeding gums, blood in the urine or stool, or heavy menstrual bleeding).
  • Drugs that deplete: antibiotics, aspirin, phenytoin, phenobarb, cholestyramine, colestipol, orlistat, and mineral oil.
  • High intake of vitamin K from foods or supplements can reduce the effi cacy of blood-thinning drugs (warfarin).
  • Most people get adequate vitamin K from the diet and/or a multivitamin.

  • Food Sources : Green leafy vegetables, cabbage, Brussels sprouts, vegetable oils (canola, soybean, cottonseed, and olive)
  • Adequate Intake : (mcg/day)*
    Men = 120
    Women = 90
    Pregnancy = 90
    Lactation = 90
  • Upper Limit : Not determined
  • Side Effects : No adverse effects known from foods or supplements; those taking anticoagulant drugs should monitor their intake of vitamin K