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Fatty liver disease is eased by soy intake

Apr 24th, 2012
Staff Writer

Soy foodsFatty liver disease is a growing problem as more people become overweight and obese. But a new study points to a possible tactic for reducing development of the disease -- through consumption of soy foods.

"Almost a third of American adults have fatty liver disease, many of them without symptoms," said the lead author of the study, Hong Chen, an assistant professor of food science and human nutrition at the University of Illinois. "Obesity is a key risk factor for this condition, which can lead to liver failure."

Fat is metabolized in the liver. But when people are obese, the transport of fat in the bloodstream to fat tissue can slow down to the point at which the liver becomes a dumping ground for excess fat, Chen said.

"When fat accumulates in an organ that's not supposed to store fat—like the liver—that organ's vital function can be dangerously compromised," she noted.

Eating soy protein, from such sources as tofu and yogurt, appears to alleviate some of the stress on fatty livers. In her study, Chen compared fat accumulation in the livers of lean and obese rats, which were assigned to either a diet containing casein, a milk-based protein, or a diet containing soy protein, for 17 weeks. While diet had no effect on the liver profiles of lean animals, the obese rats that were fed soy showed a 20 percent reduction in triglycerides and overall fat accumulation in the liver.

Furthermore, the scientists discovered that soy protein isolate partially restored a key cell signaling pathway that plays a key role in fat metabolism.

"In many obese persons, there's a sort of traffic problem, and when more fat can make its way out of the liver, there is less pressure on that organ," Chen said.

The study was presented at the annual meeting of the American Society for Biochemistry and Molecular Biology, held in conjunction with the Experimental Biology 2012 meeting in San Diego.