December 2005 Archives

Soy protein & branched-chain amino acids

As we age, our muscle and whole-body protein metabolism slows down. (Medical Reference 1) Fortunately, these changes can be offset by exercise, which provides a variety of health benefits for people of any age. However, our bodies require a good source of energy or fuel for exercise to provide its full benefits.

It has been reported that the branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, are oxidized to provide an important energy source during exercise. (Medical Reference 2) In addition, the BCAAs, especially leucine, can enhance protein synthesis after exercise and while at rest (Medical References 3-9) and may help prevent muscle breakdown and soreness associated with exercise. (Medical References 10, 11) In addition to their benefits on protein synthesis and exercise, it has been suggested that BCAA may support better immune function in athletes. (Medical Reference 12)

Soy protein has been shown to be an excellent source of BCAAs. (Medical Reference 13)

The holidays are rapidly approaching and with them the opportunity to consume lots of delicious food and drink at family gatherings and other social events. One way to help maintain a healthy lifestyle during the holidays is to eat foods with a “low-glycemic index”.

The glycemic index was first developed in 1981 (Medical Reference 1) as a new method of classifying foods based on the measurement of how dietary carbohydrates effect blood sugar responses after eating. “High-glycemic index” products, like white bread, have carbohydrates that are rapidly digested and absorbed, thus causing sharp increases in blood sugar levels. “Low-glycemic index” products, like soy protein, have carbohydrates that are slowly digested and absorbed, thus producing minimal rises in blood sugar and insulin levels. The glycemic index was later expanded to include the concept of “glycemic load”, which accounts for the amount of carbohydrates in a serving in order to better understand the impact of a meal or snack on blood sugars (Medical References 2, 3) and thus improve diet planning.