Diabetics Benefit From Supplements

March 3, 2003 -- Although the use of daily multivitamin supplements among well-fed people has long been debated, with studies providing mixed results, new research indicates that the over-the-counter pills can help people with diabetes dramatically reduce their risk of cold, flu, and other infections.

This study is among the first to look specifically at how vitamin supplements -- regularly consumed by about 40% of Americans -- impact immune function in those with type 2 diabetes, who are more susceptible to various viral and bacterial infections. Along with 51 diabetic patients, researchers also studied self-reported rates of infections in 79 people without diabetes. Everyone in the study was at least 45 years old.

Among all participants, 43% of those taking daily supplements reported getting sick during the study, compared with 73% of those getting a placebo. In those with diabetes, 93% taking a placebo got sick, compared with only 17% on the active supplements. However, in those without diabetes, there was no measurable difference between supplement- and placebo-takers.

"The take-home message of our finding suggests that vitamins may be helpful and they may not be, depending on who you are," says researcher Thomas A. Barringer, MD, research director at Carolinas Medical Center in Charlotte. "If you have type 2 diabetes, there may be something in the vitamins that seems to replete nutritional deficiencies caused by the disease."

Researchers have long known that persons with type 1 and type 2 diabetes are more prone to various infections because of impaired immunity.

"There are probably several factors," says Eugene Barrett, MD, PhD, president-elect of the American Diabetes Association. "High blood sugar seems to impede the way (infection-fighting) white blood cells work so they can't kill bacteria as well as when blood sugar is at normal levels. Studies find that controlling blood sugar makes a big difference in controlling infection."

Other research suggests that frequent urination causes diabetics to lose nutrients such as zinc and selenium -- key in keeping immunity strong. The supplements used in Barringer's study were higher-than-average in these nutrients, but still close to the formulas in most commercially available products.

Barrett tells WebMD that this study, published in the March 4 issue of Annals of Internal Medicine, is a great first step in learning more about how vitamins may help people with diabetes reduce their risk of nagging infections such as colds, flu, and urinary tract and stomach infections. "But it's a small study, so it's too early to recommend that people with diabetes take daily vitamin supplements as a matter of policy. More study is needed."

That's because based on this study, there is still question about whether it's the disease itself or the overall dietary habits of the diabetics studied that played the key role in the dramatic results.