Antioxidants: An Antidote to Aging? Reprinted from Food Insight November/December 1993 Mom always said, "Eat your fruits and vegetables, they'll help you grow big and strong." Although dietary recommendations have changed over the years, this is one bit of advice even Father Time can't ignore. According to recent studies, antioxidant vitamins in produce and other foods may actually represent a modern-day "Fountain of Youth." Evidence suggests that vitamins C and E, and beta carotene, a precursor to vitamin A, may reduce the risk of some forms of cancer, heart disease, strokes, cataracts, as well as slow the aging process. How do these compounds work and how far are scientists willing to go in touting their health benefits? Antioxidants at Work Although oxygen is vital to life, scientists are also finding this essential element may contribute to human aging and illness. When oxygen is metabolized or burned by the body, cells form byproducts called free radicals. Free radicals travel through the cell, disrupting the structure of other molecules and resulting in cellular damage. Such damage is believed to contribute to aging and various health problems. Antioxidants protect key cell components from damage by neutralizing the free radicals. Antioxidants that occur naturally in the body or are consumed through the diet may block most of the damage; however, over time, damaged cells can accumulate and lead to age-related diseases, researchers say. "Antioxidant defense systems limit [free-radical] formation and scavenge them, but antioxidant defenses are not 100 percent efficient," said Barry Halliwell, D.Sc., of the University of London and the University of California at Davis, speaking at a symposium sponsored by the International Life Sciences Institute (ILSI). Over time, "Oxidative stress can damage proteins, lipids, DNA and carbohydrates." In an effort to beef up bodily defenses to combat free-radical activity, scientists are studying the effects of increasing individuals' antioxidant levels through the diet and dietary supplements. Recent Research Among the most widely-publicized research trials on antioxidants was a five-year study published earlier this year in the Journal of the National Cancer Institute involving approximately 30,000 residents of north-central China. Participants were given either a placebo or a dietary supplement containing one of seven vitamin-mineral combinations. Persons who received a daily dose of beta carotene, vitamin E and selenium had a reduced cancer rate of 13 percent. Although many questions remain as to the significance of these findings for other populations, the study represents the first large-scale randomized, prospective, placebo-controlled study showing the benefits of dietary supplementation with antioxidant vitamins and minerals. Much of the previous evidence was based on epidemiological studies of populations, which suggested an association between antioxidants and disease prevention but were not designed to reveal cause and effect relationships. In another recent study reported at the American Heart Association (AHA) Scientific Session in November, women who consumed high amounts of antioxidant containing foods had a 33 percent lower risk of heart attack and a 71 percent lower risk of stroke, than women who ate few antioxidant-containing foods. The study involved 1,795 female nurses, each of whom had a history of heart attack, chest pain due to coronary disease, or treatment for a blockage in a coronary artery. Food intake was analyzed according to subjects' estimated consumption of vitamins C and E, carotene and riboflavin. Even after controlling for other variables that can contribute to cardiovascular risk such as age and high blood pressure, the nurses who consumed the most dietary antioxidants had the greatest disease reduction. Individual foods most closely associated with the health benefits included carrots, spinach and other greens. "These data suggest that people at high risk because of a history of cardiovascular disease or events may benefit the most from increased consumption of fruits and vegetables," said principal investigtor JoAnn Manson, M.D., of Brigham and Women's Hospital in Boston. "These women were at especially high risk, and any intervention that impacts on that risk could potentially save a large number of lives," Manson added. Health care costs related to cardiovascular disease are expected to exceed $117.4 billion in 1993 alone, according to AHA. Wait and See Despite these and other promising findings from antioxidant research studies, many experts are not yet convinced there are adequate data to allow a health claim on foods or dietay supplements. Questions still remain on issues such as the effectiveness of individual antioxidant vitamins to prevent which conditions, their mechanisms of action, optimum levels of intake and their long-term effects. Even more contentious is the issue currently being debated by Congress and the Food and Drug Administration (FDA) over whether dietary supplements containing antioxidants and other compounds should be regulated as foods or drugs. Many health groups such as AHA and the American Cancer Society believe it is premature to recommend dietary supplements containing antioxidants, indicating that some other as yet unidentified substance in fruits and vegetables may actually be responsible for reduced disease risk. "We can't yet say conclusively that antioxidant vitamins, per se, as opposed to foods that are high in antioxidants, can reduce the risk of stroke or heart attack," Manson said. "I would support the public health recommendation for increased fruit and vegetable consumption among people who at high risk for cardiovascular disease, as well as for the general public. But, at this point, I couldn't recommend that people buy vitamin supplements." "We're in the first wave," said Nancy Ernst, M.S., R.D., nutritional coordinator at the National Heart, Lung and Blood Institute who spoke at the ILSI symposium. "We need to call for more research. We have a lot of answers but we also have many, many questions... We've not sufficiently addressed issues such as other nutritive and non-nutritive compounds in the diet that may contribute to disease prevention." Upping the Antioxidant Ante Until further studies are completed, eating a balanced diet rich in antioxidant vitamins may be the best way of improving your health. The folloiwng chart outlines foods high in antioxidants. Resolve to include more of these foods in your daily diet. VITAMIN FOODS Vitamin A liver, egg yolk, fortified milk, butter, margarine, Beta Carotene spinach, carrots, squash, broccoli, yams, tomato, cantalope, peaches, fortified grain products Vitamin C citrus fruit and juices (oranges, grapefruit), strawberries, kiwi, cantalope, green peppers, raw cabbage, spinach, kale, broccoli Vitamin E nuts, seeds, whole grains, vegetable and fish-liver oils, fortified cereals, dried apricots Taking Action Although much of the scientific community is still calling for further research on antioxidants before changing public health recommendations, some consumers aren't waiting for more data. According to Catherine E. Woteki, Ph.D., R.D., of the National Academy of Sciences, "Data on supplement sources of nutrient antioxidants show that 36 percent of adults report using vitamin/mineral supplements. Food supply data and limited data on intakes and supplement use indicate that levels of vitamins E and C and the carotenoids in the diet have increased among Americans." Some nutritionists and policymakers are concerned that individuals will take excessive amounts of supplements, believing that if a little bit is good, more must be better. High doses of some antioxidants can produce adverse affects in people; for example, excessive vitamin E can interfere with the action of warfarin, a blood-thinning medicine often prescribed for patients with heart disease. FDA is examining the scientific data to determine whether there is adequate scientific data to support a health claim on antioxidants and disease prevention and is expected to make a decision sometime next year. Reprinted from the International Food Information Council Foundation, 1993

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