Vitamins C and E May Reduce Risk, Complications of Diabetes

From the WebMD Archives

Nov. 15, 2000 -- Simple, over-the-counter vitamins -- namely E and C -- might someday be credited with preventing some of the most serious diabetes-related complications and may even delay the development of the disease. These are encouraging concepts for diabetics and nondiabetics alike, and in fact, are showing promise in research studies across the country.

On Monday, some of the leading researchers presented their latest findings by teleconference about the role of vitamins E and C in reducing the complications of the disease that affects an estimated 16 million people in the U.S.

"And with 50% of the population being overweight, that number will only increase," James Anderson, MD, professor of medicine and clinical nutrition at the University of Kentucky in Lexington, tells WebMD.

Vitamins C and E are antioxidants, compounds that prevent damaging effects to the body by "oxygen free radicals." These unstable molecules are a natural byproduct of the body's normal metabolic process where it burns glucose to provide energy to cells. Diabetics have elevated sugar levels, therefore, more free radicals are generated.

Anderson, the author of Dr. Anderson's Antioxidant, Anti-Aging Health Program, says, "There is mounting evidence that antioxidant vitamins have anti-inflammatory [as well as] antioxidant properties. I believe that in the next five years, vitamin E supplementation will become the standard of care for diabetes. We're making progress, but we're not there yet."

Still, Anderson's extensive research with vitamin E has led him to believe that the benefits of taking antioxidants is so favorable, that all adults should take 800 IU of vitamin E as a preventive measure, which is far above the Recommended Daily Allowance of 10 mg for adults. The maximum amount that can be taken safely is not known, but most experts agree that up to 1,200 IU a day is safe.

Of major concern for people with diabetes is heart and blood vessel disease, and for good reason. Data from the Centers for Disease Control and Prevention show that heart disease and stroke are two to four times more common among persons with diabetes.


Heart disease causes more than 70% of deaths in diabetes, according to Ishwarial Jialal, PhD, professor of internal medicine and pathology and co-director of the Lipid Clinic at the University of Texas Southwestern Medical Center at Dallas. "The diabetics' risk for heart disease is so great, it's [a good idea] to take an antioxidant supplement because it not only functions as an antioxidant, but anti-inflammatory [as well]," he says.

John Cunningham, PhD, professor of nutrition at the University of Massachusetts at Amherst, has been instrumental in establishing an important role for vitamin C in reducing the complications of diabetes. "Many diabetic patients have low levels of vitamin C in the cells and could benefit from getting more vitamin C," he says.

While it's unclear whether high doses of the vitamin will be effective, 100 mg of vitamin C or a diet rich in vitamin C-containing foods might be adequate, he says. Smokers, however, may need a bit more.

Vitamins attained through diet are extraordinarily important for the diabetic patient, according to Anderson. "Most evidence suggests a higher fiber diet rich in whole grains, fruits, and vegetables, and lower fat."

Natural foods rich in vitamin E include almonds, peanut butter, margarine, wheat germ, sunflower oil, kiwi, broccoli, and eggs. Vitamin C-rich foods include papaya, orange juice, strawberries, cantaloupe, green peppers, broccoli, and tomatoes.

"The more we examine the components of a healthy diet, the closer we get to being able to make better individual recommendations about one's ideal food intake pattern," nutritionist Maggie Powers, MS, RD, CDE, tells WebMD. "This new information will encourage me as a dietitian to have open discussions about nutritional supplements with persons with diabetes." Powers is co-author of Forbidden Foods Diabetic Cooking.

"Even if research is inconclusive or raises more questions," Powers says, "it contributes to the discussion and advances our ability to decipher recommendations and provide improved patient care. Vitamins E and C are important vitamins and may have even more to contribute than once thought. Yet, research suggesting that either vitamin promotes improved blood flow or improved blood glucose levels is too inconclusive to suggest a broad recommendation to supplement all diets of people with diabetes."


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