Researchers from Vanderbilt University Medical Center and the Shanghai Cancer Institute recruited 64,227 middle-aged Chinese women with no previous history of diabetes, cardiovascular disease or cancer, and followed them an average of 4.6 years.
Food-frequency questionnaires revealed an inverse association between eating legumes and incidence of type-2 diabetes. A high intake of all legumes resulted in a 38% reduction in risk, while a high intake of soybeans, specifically, was associated with a 47% risk reduction. (Villegas R, Gao YT, et al. Am J Clin Nutr)
Research conducted at the University of Massachusetts Amherst also suggests soy, in the form of soy yogurt, could play an important role in the management of type-2 diabetes and high blood pressure. (Shetty K., UMass Amherst)
Type 2 diabetes can often be accompanied by an abnormal rise in blood sugar right after a meal. Medications to prevent this often target enzymes responsible for modifying carbohydrates before they can be absorbed by the small intestine. Since carbs are the major source of blood sugar, inhibiting carb-altering enzymes-Á-amylase and Á-glucosidase-slows the body's absorption of sugars.
High blood pressure is another problem for which diabetics are at increased risk, so the U Mass researchers also took a look at soy yogurt's effects on the activity of angiotensin-I converting enzyme (ACE-I), which plays a role in the constriction of blood vessels and is a target of blood pressure-lowering medications (ACE-inhibitors).
Buying peach, strawberry, blueberry and plain yogurts made by four different brands, including a soy brand, at the local grocery, the researchers took samples of each yogurt and tested its ability to inhibit the three enzymes.
The soy yogurt enriched with blueberries inhibited the activity of all three enzymes. The blueberry (non-soy) yogurts were also best at blocking the action of Á-glucosidase. Peach and strawberry enriched yogurts inhibited both carb-altering enzymes, Á-amylase and Á-glucosidase.
The researchers also tested the yogurts for their phenol content (phenols are potent anti-oxidants and are sometimes even more potent than vitamin antioxidants) and levels of antioxidant activity. Blueberry yogurts had the second-highest concentrations of phenols and the most antioxidant activity, surpassed only by soy (even plain soy yogurt had higher phenol content than any regular yogurt with fruit). Soy yogurts had the highest phenol content overall, and were best at inhibiting ACE-I, lessening its activity by 92%.
The findings provide a strong rationale for further clinical studies, and for incorporating "healthy diet design" into disease management strategies. "What one eats should be part of an overall approach to therapy," said lead researcher Kalidas Shetty.
Practical Tip: Give soy yogurt a try. Instead of buying fruit-flavored yogurt, though, we recommend adding your own fresh blueberries, strawberries or peaches to plain yogurt. You'll get far more fruit and along with it, we expect you'll also get more more carb- and ACE-1-enzyme-inhibiting activity as well.