Soy for Postmenopausal Women with Type 2 Diabetes

Postmenopausal women with adult-onset diabetes (type 2) may be able to reduce their total cholesterol and insulin levels by consuming soy protein enriched with isoflavones, according to a study in Diabetes Care (2002;25:1709–14). Since high cholesterol and elevated insulin levels are known risk factors for heart disease, these findings suggest that consumption of isoflavone-enriched soy protein may reduce the risk that a person with diabetes will suffer a heart attack or stroke.

Risk factors for type 2 diabetes include obesity, smoking, consuming excess alcohol, and sedentary lifestyle. Uncontrolled diabetes is a serious health problem that can lead to several complications, such as heart disease, blindness, nerve damage, and kidney failure. Conventional treatment for type 2 diabetes includes oral medications that increase the release of insulin from the pancreas or enhance the blood sugar-lowering action of insulin; however, these medications may cause side effects such as nausea, vomiting, or abdominal pain, whereas soy protein is not associated with any adverse side effects.

This 24-week study examined the effect of soy protein (30 grams per day; providing 132 mg per day of isoflavones) or placebo in 32 postmenopausal women with type 2 diabetes. The study was designed as a crossover study, so that participants received both treatments during two separate 12-week periods. Several measurements of blood sugar control and heart diseases risk factors were taken at the beginning and end of each treatment period.

Consumption of soy protein had a statistically significant impact on blood sugar control and lipid levels. Compared with the pretreatment values, fasting insulin and insulin resistance were reduced by 8% and 6.5%, respectively, after consumption of the soy protein. These improvements were significantly greater than those seen during the placebo period. Total cholesterol and LDL (“bad”) cholesterol were also significantly lowered after eating soy.

The authors point out that the results of this study are comparable to those of studies on oral hypoglycemic medications, suggesting that isoflavone-enriched soy protein may be as effective as conventional medications in controlling insulin levels. However, since this study did not compare soy protein with a conventional medication, it is unknown if this speculation is true.

Other nutritional supplements that have been used improve blood sugar control in people with diabetes include chromium, biotin, and vitamin E. Because some nutritional supplements and herbal remedies can interact with diabetes medications, potentially resulting in dangerously low blood sugar levels, people taking such medications should consult a doctor knowledgeable in natural medicine before taking any supplements or herbs.

Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of The Natural Pharmacist: Lowering Cholesterol (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice at New England Family Health Associates located in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.

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