Soy boosts growth factor in men

Science has uncovered a host of soy-related benefits for women over the past decade, but just what's in it for men?

 

In what is believed to be the first study into the effects of soy protein on men, researchers from Oklahoma State University recently found that men taking a soy protein supplement improved their IGF-1 levels by 100 per cent.

 

Released from the liver after being stimulated by growth hormone, IGF-1 (insulin-like growth factor) is the major regulator of body growth. From about age 30 onwards, men commonly experience a decline in IGF-1 along with growth hormone.

 

Scientists from Oklahoma State University randomly assigned 64 healthy men to take either soy- or milk-based protein supplements for 3 months. Nineteen of the men were older than 65. The researchers compared levels of IGF-I before and after supplementation.

 

Dr. Dania A. Khalil presented the group's findings at the Experimental Biology 2001 meeting in Orlando, Florida on 4 April 2001.

 

She said that IGF-I increased tremendously in both groups - 20% in men using the milk-based protein supplement and nearly 100% in those using soy protein. In the older men on soy protein, serum IGF-I levels more than doubled.

 

Aussie Bodies nutritionist Leigh Blashki says that although Whey Protein Concentrate has long been the staple protein source for the majority of nutritionally-aware bodybuilders, the benefits of soy protein as an agent in muscle recovery cannot be underestimated.

 

"WPC has long been shown to precurse and assist growth processes in a number of ways, including the elevation of IGF-1 levels.

 

"Soy protein isolate, as in Solae (TM) and Supro (R) soy protein, contains equally bioactive protein but also contain isoflavones. Because the activity of isoflavones mimics that of estrogen, tests to date have focused largely on the ways isoflavones can precurse hormonal regularity and overall health in women, further adding to the misperception that soy protein is a supplement for women.

 

"But as the Oklahoma study has shown, isoflavones can assist growth and recovery in men by elevating IGF-1. In addition to this, the antioxidant properties in soy isoflavones have been found to shorten recovery time between training sessions by reducing the oxidative stress that leads to exercise-induced injury."

 

Australian products containing these soy proteins include Perfect Soy Protein, Soy Protein Plus, Protein FX bars, Life Protein Shake, Life Pure Soy Protein and the Aussie Bodies TRIM product range.