A new report on Dietary Reference Intakes from the Institute of Medicine of the National Academy of Sciences examined whether chronic diseases can be prevented with dietary antioxidants such as vitamins C and E, selenium, and cartenoids. While the report concluded that there was not sufficient evidence to support the claim, it did issue new guidelines for recommended dietary allowances for these substances.
Oxidants are agents that affect the molecular composition of a cell. The role of antioxidants in preventive medicine is a very active area of scientific research. Although a direct connection between the intake of antioxidants and the prevention of chronic disease has not been adequately established to date, dietary antioxidants can prevent or counteract the cell damage that comes from exposure to oxidants. The following are recommendations for antioxidant intake.
Vitamin C - For maximum body saturation, women should consume 75 milligrams (mg) per day, and men, 90 mg per day. People who smoke should consume an additional 35 mg daily because smoking damages cells and depletes vitamin C. Citrus fruit, potatoes. strawberries, brccoli and leafy green vegetables are recommended food sourcesof Vitamin C. Intake of Vitamin C from food or ascorbic acid from supplements should not exceed 2000 mg daily because of the risk of diarrhea development at higher doses.
Vitamin E - Men and women should consume 15 mg per day from foods such as vegetable oils, nuts, seeds, liver, and leafy green vegetables. There is no upper limit of intake of Vitamin E from food, but people who take Vitamin E supplements should not exceed 1500 International Units (IU) per day of d-alpha-tocopherol because of the risk of hemorrhaging from the anticoagulant effects of the nutrient.
Selenium - Recommended daily intake of selenium is 55 micrograms (mcg) daily from seafood, liver, meat, and grains. No more than 400 mcg should be consumed daily from food or supplements, or selenosis might develop, causing hair loss and nail sloughing.
Cartenoids - Because of conflicting studies, no recommended daily intake level for carotenoids was offered. Supplementation should only be used for the treatment of Vitamin A deficiency.