Dr. Jeffrey Blumberg, chief of the Antioxidant Research Lab at the Jean Mayer United States Department of Agriculture (USDA) Human Nutrition Research Center on Aging at Tufts University, believes the evidence is very compelling that as you increase your intake of certain antioxidants, you increase the benefits.



Antioxidants and Free Radicals:

The body's use of oxygen creates byproducts called free radicals are formed. These oxygen molecules are missing an electron making them very unbalanced. Therefore, they steal electrons from healthy cells, causing damage to the victimized cell.

It is believed that this cell damage is cumulative. Scientists theorize this may lead to aging and disease. It's possible that everything from cancer and heart disease to wrinkles and cataracts is the result of the action of free radicals. Environmental factors including exposure to radiation and tobacco smoke may also increase the number of free radicals in the body.

Compounds known as antioxidants prevent cell damage by deactivating free radicals. Vitamins E and C and beta carotene are the best known antioxidants, but there are many others, including selenium, lutein, and lycopene.

Positive Findings

A five year Chinese study that involved 30,000 participants demonstrated that the participants who received a daily supplementation of Vitamins E, selenium, and beta carotene had a 13% lower rate of cancer than those study participants who received a placebo.

A U.S. study of 1,795 nurses with a history of heart problems showed that the nurses who consumed larger amounts of Vitamins C and E and beta carotene showed the greatest cardiac improvement and reduced their chances of further heart damage.

The May 20, 1993 issue of The New England Journal of Medicine cited a study that reported a significant decrease in the incidence of coronary artery disease in men and women who consumed 100 international units (IU) of Vitamin E daily. This amount is about 6 times the current recommended daily intake for Vitamin E.

Inconclusive Findings:

The results a 4-1/2 year study of more than 9,500 men and women age 55 and older with risk factors for heart disease were reported in the January 2000 issue of The New England Journal of Medicine

Half of the study participants were given 400 IU of Vitamin E from natural sources, while the other participants received a placebo. During the term of the study, there was no significant difference in the number of cardiac events or cardiac deaths in either group.

You may be wondering why these studies contradict the results of other studies. The researchers themselves note that perhaps the study wasn't long enough to demonstrate any effect. They also suggest that perhaps the findings were influenced because they used Vitamin E supplementation alone, without any other antioxidants. Vitamin E may require other factors to achieve its beneficial effect.

Too Much of a Good Thing?

In 1994, studies of beta-carotene in humans were stopped after results suggested that people at risk for cancer were at a greater risk after taking high doses of synthetic beta-carotene. Some critics of this study have pointed out the use of synthetic vs. natural.

Benefits of Dietary Changes Are Clear:

As pointed out by Dr. Blumberg, research is ongoing. He cites new studies showing the benefits of lesser known antioxidants such as lycopene, which may help reduce prostate cancer risk, and lutein, which is strongly associated with a decrease in age-related macular degeneration and prostate cancer.

Studies of high-risk groups, such as the nurses with heart disease, suggest the greatest benefit from increased consumption of antioxidants is realized by those at the greatest risk of disease. Consuming more antioxidant-rich fruits and vegetables has well-documented benefits for improving health, apart from their antioxidant contents.

Are Supplements Necessary?

For many people, it is very difficult to consume enough fresh fruits and vegetables to receive any kind of benefit.

Few people consume the recommended daily intakes for all nutrients. Dr. Blumberg says as people grow older, they eat less. "As their appetite decreases, they don't change how they eat, they just eat less."

Instead of adding more fruits and vegetables to their diets, many older people eat smaller portions of the same kinds of foods they've eaten for years, which are often high in fats, starches, and sugars.

Smokers, heavy drinkers, people with impaired immune systems, and those on calorie-restricted diets may also have difficulty getting the nutrients they need from food alone. For these people in particular, supplements may be the only way for them to fulfill their nutrient needs.

In addition, Vitamin E is found in a limited number of foods, making it difficult to get enough of it from the average diet. Consuming more fruits and vegetables is the best way to get essential nutrients, a good multivitamin can fill in any nutrient gaps.

REFERENCES:

The heart outcomes prevention evaluation study investigators, vitamin E supplementation and cardiovascular events in high-risk women. New England Journal of Medicine. 2000;342: 154-160.

Luchsinger JA, Mayeux R. Dietary factors and Alzheimer's disease. Lancet Neurol . 2004 Oct;3(10):579-87.

Meydani M. Nutrition interventions in aging and age-associated disease. Ann N Y Acad Sci. 2001 Apr;928:226-35.

Miller ER III, Pastor-Barriuso R, Dalal D, Riemersma RA, Appel LJ, Guallar E. Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med. 2005 Jan 4;142(1):37-46.

Stanner SA, Hughes J, Kelly CN, Buttriss J. A review of the epidemiological evidence for the 'antioxidant hypothesis'. Public Health Nutr. 2004 May;7(3):407-22.