Soy Story: Can Supplements Help Diabetics Avoid Heart Disease?

From the WebMD Archives

Feb. 21, 2001 -- People with so-called type 2 diabetes take fistfuls of medications, and they're not all aimed at controlling blood sugar. Because diabetics are at an increased risk of heart disease, they are often on blood pressure and cholesterol drugs as well. It's no wonder, then, that the idea of a dietary supplement that could do the work of one of these medications is appealing.

Previously, soy-based dietary supplements have been shown to boost the effect of a low-fat diet in lowering cholesterol in people withoutdiabetes. People withdiabetes may also benefit, it appears, according to a study in the February issue of the journal Diabetes Care.In their article, the Scandinavian research team says the positive effects of soy can also be seen in people with type 2 diabetes -- formerly known as "adult-onset" or "non-insulin-dependent diabetes."

"Soy-based dietary supplementation seems to possess the ability to effectively reduce [cholesterol] levels in people with type 2 diabetes who are especially prone to develop heart disease," lead author Kjeld Hermansen, MD, tells WebMD. "Such a supplement may [help postpone] the requirement for drug therapy for these patients."

Any dietary supplement used to ward off the need for cholesterol-lowering medication should also be combined with lifestyle changes such as increased exercise, smoking cessation, and a low-fat diet, stresses Hermansen, an associate professor of endocrinology at Aarhus University Hospital in Aarhus, Denmark.

He and colleagues from Aarhus and from the Nutri Pharma company in Oslo, Norway, came to their conclusion after a 15-week study of 20 patients with type 2 diabetes. For six weeks, the diabetic patients received a soy supplement, and then they were switched to six weeks of an identical-looking placebo. These two sessions were separated by three weeks of no treatment.

Doctors found that the patients' cholesterol levels were significantly lower after the six weeks of soy supplements than it was when measured after taking the inactive placebo drug. Among their findings: LDL or "bad cholesterol" levels decreased significantly with the soy; triglycerides and HDL or "good cholesterol" levels remained about the same regardless of which treatment they got; and levels of a blood protein called homocysteine, a known indicator of heart disease, was raised during both the soy and non-soy treatments, although the rise was less marked during the soy-treatment period.


That's all well and good, say some experts -- but exactly how much long-term advice can be given from the results of such a brief study, and how practical would such a supplement be to take?

"The study showed that this soy-based dietary supplement lowered some of the important aspects of total cholesterol over a short period of time," says Richard Hellman, MD, who reviewed the study for WebMD. "That's useful information, but we don't know what the implications are at six months, for example, or three years."

Hellman is a member of the board of directors of the American Association of Clinical Endocrinologists and is a clinical professor of medicine at the University of Missouri in Kansas City.

"The approximate 10% reduction in LDL cholesterol is pretty impressive. It's a nice decrease for a dietary reduction," says Mark Messina, PhD, but the amount of soy the subjects received, 50 grams daily, is relatively high.

"I like to see smaller amounts of soy used because they're more realistic," says Messina, an adjunct associate professor of nutrition at Loma Linda University in Loma Linda, Calif. "I'm more impressed with 25 grams giving a 5-6% reduction, because 50 grams daily is difficult to do over the course of a person's life."

And beyond that, getting more soy in one's diet is not always a good thing, James Braly, MD, tells WebMD.

"Soy consumption has tripled in the last three years," says Braly, vice president of medical services for Health Trust Alliance and a clinical nutrition investigator in Summerlin, Nev. "During that time there has been an increase in allergic reactions to soy. People should keep a balanced perspective and realize that although there are benefits to including soy in the diet, there may also be a downside."

The study was funded by grants from Aarhus University and Nutri Pharma ASA, which manufactures Abalon, the soy product used in the study.

WebMD Health News Reviewed by Gary D. Vogin, MD
© 2001 WebMD, Inc. All rights reserved.