Eating foods rich in antioxidants is one part of a diet and exercise program that protects against chronic diseases, according to LSU AgCenter nutritionist Dr. Heli Roy. A recently published study bears out this claim.
In a recent issue of "American Journal of Clinical Nutrition," an extensive, 20-year nurse’s health study found that those who had the highest carotenoid intake had the lowest relative risk of coronary heart disease. For those who consumed the most carotenoids, the risk was reduced by 26 percent compared to the lowest intake.
Carotenoids are antioxidants, compounds that help protect against free radicals that attack molecules and modify a cell’s chemical structure. One of the causes of free radical formation is oxygen. Oxygen in the cells can cause damaging byproducts during metabolism.
Roy says antioxidant compounds in the diet can counteract these byproducts and eliminate them. If free radicals are left in the cells, they can eventually lead to heart damage, cancer, cataracts and a weak immune system.
Antioxidants bind to free radicals to neutralize them, transform them into harmless compounds and repair cellular damage caused by free radicals. Dietary antioxidants are vitamin C, vitamin E, the carotenoids and selenium.
Vitamins A, carotenoids and vitamin E are lipid (fat) soluble compounds and are stored in the adipose tissue (the body’s fat layer) and in lipoproteins, which transport the compounds through the blood.
Carotenoids protect lipids against peroxidation, the formation of harmful compounds when free radicals attack fatty acids in the cells.
During the 20 years of the study, 998 incidences of coronary artery disease occurred. When the participants were divided into five groups based on total carotene intake, those who had the highest carotene intake had the lowest relative risk of coronary heart disease. In the highest group, the risk was reduced by 26 percent compared to the lowest intake.
Previous studies indicate that taking supplements of isolated carotenoids and antioxidant vitamins is not as effective as consuming foods that are high in antioxidant molecules. "There are many different kinds and variations of antioxidant molecules in foods," the LSU AgCenter nutritionist says, explaining that just isolating one or two for supplemental intake may not be as effective as the whole range of different antioxidant molecules together in foods.
Roy says good sources of antioxidants include fruits and vegetables. The highest concentrations are in the most deeply or brightly colored fruits and vegetables, such as spinach, carrots, red bell peppers and tomatoes. The current Dietary Guidelines for Americans 2010 recommends that we eat 5.5 cups of red and orange vegetables a week in order for us to get adequate amount of carotenoids to protect us from chronic diseases.
Citrus fruit, berries, green leafy vegetables and sweet potatoes are excellent sources of antioxidant nutrients. The USDA Food Guide recommends 2 cups (4 servings) of fruits and 2.5 cups (5 servings) of vegetables daily. Servings are small and can be easily met each day with some planning.
Roy also suggests contacting an extension agent in your parish LSU AgCenter office to learn more about healthy eating.