A new review of human populations, animal studies, and clinical trials supports the role of soy protein to reduce cholesterol levels, and aid weight loss

February 01, 2008

According to the review by researchers at the University of Alabama at Birmingham and the University of Illinois at Champagne-Urbana, say that Soy Protein also has the added benefits of boosting bone health and aiding overall cardiovascular health. Soy protein has received attention for its ability to lower cholesterol and other dangerous blood fats, as well as the ability to lower blood pressure, improve the function of blood vessel walls and the function of arteries, decrease insulin resistance and increase weight loss in obesity.
The researchers collected results from in vitro, animal, epidemiologic, and clinical studies.
The review, including results from eight human studies, found that weight loss was equivalent and, in some cases, equal when using soy protein, meal replacements, or high protein meats (as in the Atkins Diet) at equal calorie levels.
Moreover, there was a suggestion that soy protein may decrease short-term appetite improving management of calorie intake.
They also reviewed the evidence concerning soy isoflavones aiding diabetes by stopping fat tissue build up and enhancing fat breakdown. Good evidence does exist including improving blood glucose and insulin levels as a result of consuming a soy-based diet, but studies duplicating these effects are desirable.
The review also supported reports of the cholesterol-lowering benefits of soy, and that soy may reduce bone loss in women.
Soy is a very complex food that has many constituents especially soy protein and soy isoflavones. "The specific soy protein components and soy constituents that may cause these metabolic improvements are not known and it will require more extensive experimentation to determine which components and constituents are involved," stated the researchers. The study is published in Obesity Reviews; the journal of the International Association for the Study of Obesity.

Habitual consumption of soybeans and isoflavones may increase bone mineral density in young women, suggests a new study that adds to others looking at older women.

The small study followed young Korean women for two years, with regular and detailed assessment of dietary intakes using 24-hour recall, supporting the reported benefits observed previously with postmenopausal women. A recent meta-analysis of existing studies published in the journal Clinical Nutrition reports that doses of soy isoflavones less than 90 mg/d may improve bone density in older women. Moreover, other studies from China have linked soy isoflavones to increases in bone mineral density (BMD), and a recent large study in the Archives of Internal Medicine reported that high soy consumption was linked with a 48 per cent decrease in fractures for women who had been menopausal for less than 10 years.
The new study measured the bone mineral density (BMD) at the lumbar spine and femur of the women (average age 22.1) three times during the two-year period using dual x-ray absorptiometry. Song and co-workers report that every one milligram of isoflavone intake was associated with a 0.26 per cent increase in bone mineral density per year in the neck of the femur, and a 0.31 per cent increase in the Ward's triangle area of the femur. The study is published in the January 2008 issue of the journal Nutrition Research.