Tofu, edamame, soy burgers—yes, they’re trendy good-for-you foods, but if you’ve got type 2 they’re particularly good for your heart and kidneys, says a new small study. Researchers looked at 41 people, average age 62, with type 2 and mild nephropathy, a complication in which the kidneys function poorly. For four years, about half of them followed diets in which the protein they ate was 35 percent animal protein, 35 percent textured soy protein, and 30 percent vegetable protein. The other half ate 70 percent animal protein and 30 percent vegetable protein. All were taking comparable types and doses of lipid-lowering and blood pressure–stabilizing medication.

After four years, the soy- protein eaters scored better on blood testing than the other group: They reduced their fasting plasma glucose by 20 mg/dl; their LDL, or “bad,” cholesterol by 21 mg/dl; and their overall serum triglycerides by 25 mg/dl—compared with minimal reductions (and even gains) for the other participants.

They also leaked significantly less protein into their urine, a sign that their kidneys were functioning better than those of other people in the study. Lead researcher Leila Azadbakht, PhD, a nutrition professor at Isfahan University of Medical Sciences in Iran, credits the lipid changes for the kidney improvements. She and her research team note, however, that their findings need to be verified in larger studies. Also, this study looked only at soy protein benefits. Other types of soy, such as soy nuts, could be an even bigger boon to people with diabetes.

The findings appear in the Apr. 2008 issue of Diabetes Care.