This study included 4,176 men and women at risk of AMD who were participants in the Rotterdam Study, which enrolled 7,983 men and women aged 55 or older. Nutrient intake was assessed via food frequency questionnaires completed by all subjects. Participants underwent eye examinations upon enrollment, and three times during the eight year follow-up. 560 subjects were diagnosed with new macular degeneration during the follow-up period. Participants with an above-median intake of all four nutrients including beta carotene, vitamin C, vitamin E, and zinc, had a 35 percent reduced risk of AMD compared to those whose intake of any of the nutrients was below average.

This study suggests that the risk of developing AMD can be modified by diet; in particular, by the dietary antioxidants beta carotene, vitamin C, vitamin E, and zinc.

Yale University researchers evaluated dietary records of participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC). A group of over 27,000 Finnish male smokers aged 50-69 had food records analyzed along with intakes of carotenoids, flavonoids, vitamin E, selenium, and vitamin C. After evaluating the overall intake of antioxidants in this group, the conclusion differs somewhat from the original study.

According to this new analysis, the men with higher overall intakes of antioxidants had lower relative risks of lung cancer, regardless of their assigned study group (beta-carotene or placebo). While researchers of the ATBC study concluded that high-dose beta-carotene supplementation may increase lung cancer risk in male smokers, these findings support the hypothesis that a combination of dietary antioxidants reduces lung cancer risk in men who smoke.

Treatment of animals with the antioxidants resulted in a 4-fold reduction in the incidence of prostate cancer compared with the untreated animals. Prostate cancer developed in 73.68% (14 of 19) and 100% (19 of 19) of the animals from the standard and high fat diet, respectively.

In contrast, tumors developed in only 10.53% (2 of 19) and 15.79% (3 of 19) of the animals in the standard and high fat diets supplemented with antioxidants.

These observations support results from a growing body of research indicating a significant protective benefit of antioxidants on the development of prostate cancer.

Some examples of scientific evidence are the following:

Cancer

• People with high beta-carotene intakes have about one-third the cancer risk as people with low beta-carotene intakes. Peto R. Cancer Surveys 1983;2:327-340.
• People with higher intakes of vitamin C have about half the risk for many types of cancer, compared to people with low vitamin C intakes. Block G. Am J Clin Nutr 1991;53:270S-282S.
• People with low intakes of several antioxidants have more DNA damage than people with generous intakes. Ames BN. Metat Res 2001;475:7-20.
• People with the highest intakes of vitamin C, E, and beta-carotene have a significantly lower risk of lung cancer. Yong LC et al. Am J Epidemiol 1997;146:231-43.
• Men who took vitamin E supplements for 10 years or more had a 30% lower risk of bladder cancer. Michaud DS et al. Am J Epidemiol 2000;152:1145-53.
• There are over 66 studies showing cancer-prevention activity of green tea, black tea, and their constituents. These include cancer reduction in the skin, lung, oral cavity, esophagus, stomach, liver, pancreas, bladder, small intestine, colon and prostate. Lambert JD et al. Am J Clin Nutr 05;81:284S- 291S.

Heart Disease

• Elderly people who took dietary supplements of both vitamin C and vitamin E had a decreased risk of death from heart disease as well as overall mortality. Losonczy KG, Harris TB, Havlik RJ. Am J Clin Nutr 1996;64:190- 196.
• Men who took vitamin supplements had a 70% lower risk of dying from heart disease and a 50% lower risk of a heart attack. Meyer F, Bairati I, Dagenasis GR. Can J Cardiol 1996;12:930-934.
• In the Nurses' Health Study involving over 87,000 women, there was a 41% reduction in risk of heart disease for those who took vitamin E for more than two years. Stampfer MJ, Hennekens CH, Manson JE, et al. New Engl J Med 1993;328:1444-1449.
• In the Nurses' Health Study vitamin C supplements were also related to a lower risk of heart disease. Osganian SK et al. J Am Coll Cardiol 2003;42:246-52.
• In the Health Professionals Follow-Up Study involving almost 40,000 men, there was a 37% reduction in risk of heart disease in men who took vitamin E for more than two years. The average intake in the lowest risk group was 400 IU per day. Rimm EB, Stampfer MJ. Ascherio A, et al. New Engl J Med 1993;328:1450-1456.
• To date, 17 human group studies have been published on flavonoid intake and the risk of coronary artery disease and stroke. Positive studies have shown reduction in mortality risk of up to 65%. Arts ICW and Hollman PCH. Am J Clin Nutr 2005;81:317S-325S.
• The largest and longest study to date, done as part of the Harvard- based Nurses' Health Study and Health Professionals Follow-up Study, included almost 110,000 men and women whose health and dietary habits were followed for 14 years. The higher the average daily intake of fruits and vegetables, the lower the chances of developing cardiovascular disease. Compared with those in the lowest category of fruit and vegetable intake (less than 1.5 servings a day), those who averaged 8 or more servings a day were 30% less likely to have had a heart attack or stroke. Joshipura KJ, et al. Ann Intern Med 2001 Jun 19;134(12):1106-14.

Other Chronic diseases

The major vitamin antioxidants are vitamin C, vitamin E, beta-carotene, while selenium is the major mineral antioxidant. Many researchers and nutritionists discuss and report on "antioxidants" as if these were the only sources of importance. A thorough examination of antioxidants and their importance to human health must include a much larger list of compounds that are present in healthy, varied diet. The following list is an example of the wide variety of phytonutrient antioxidants present in a healthy diet:

Overall, polyphenols are the most abundant antioxidants in the diet. Their total dietary intake could be as high as 1 gram/day in a mixed, varied diet of fruits, vegetables, grains, and beverages.

Possible intakes of other phytonutrient antioxidants would be anthocyandins " 2 oz black grapes 1,500 mg; proanthocyanidins " 100-300 mg/d red wine; catechins " 50 mg day " tea (one cup brewed green tea " 240-320 mg catechins), chocolate, apples, pears, grapes, red wine; isoflavones " 50 mg/day from soy foods; chlorogenic acid " as high as 800 mg/day coffee drinkers.

Although it may seem reasonable that a consistently healthy and varied diet could provide high doses of antioxidants, the average American gets a total of just three servings of fruits and vegetables a day. The latest dietary guidelines call for five to thirteen servings of fruits and vegetables a day, depending on one's caloric intake. For a person who needs 2,000 calories a day to maintain weight and health, this translates into nine servings, or 4½ cups per day.

The 2001-2002 NHANES survey of dietary intakes shows that 93% of Americans fail to get even the Estimated Average Requirement (EAR) for vitamin E, let alone the RDA. More than half of adults fail to get even the average requirement for vitamin A. About one-third of non-smokers and two-thirds of smokers fall short on minimum vitamin C requirements.

If the governmental dietary recommendations are meant to be taken seriously, then it follows that it would be better for people to achieve recommended amounts of nutrients than to fall short. Obviously, since the average intake of 3 servings or less of fruits and vegetables fails to provide minimum levels of even basic vitamins, intakes of the numerous other antioxidants are sure to be well under optimal and beneficial levels.

Antioxidants are molecules that can safely interact with free radicals and terminate the chain reaction before vital tissues and cells are damaged. Although there are several enzyme systems within the body that scavenge free radicals, the principle micronutrient (vitamin/mineral) antioxidants are vitamin E, beta-carotene, vitamin C and selenium. The body cannot manufacture these micronutrients so they must be supplied in the diet. In addition, there are literally hundreds of plant derived nutrients (phytonutrients) that act as important antioxidants in the diet.