New Study Shows Soy Protein Reduces Effects of Fatty Liver Disease

Decreases in blood cholesterol and fatty liver tissue were shown with a diet high in soy protein

ST. LOUIS, Nov 14, 2011 – The positive effects of soy protein to reduce higher than normal blood cholesterol have been studied and proven in recent years. However, a study published online in Hormone and Metabolic Research showed the positive effects of soy protein isolate in obesity-related conditions such as inflammation and fatty liver disease.
The study looked at lean and genetically obese rats to determine the effects of a diet high in soy protein isolate, sodium caseinate or dairy whey protein on obesity-related metabolic dysfunction, a condition that exists in people who are overweight and which can lead to the development of Type 2 diabetes. All diets were identical except for the source of protein and were fed to the rats for 17 weeks. Solae provided the soy protein for the experiment.

“There was a clear reduction in liver fat content and in some key inflammatory markers in the soy-fed animals, but we need to do more work to follow up on these promising results,” said Dr. Jeremy Davis, Assistant Professor, Animal Science, Food and Nutrition at Southern Illinois University Carbondale and author of the study. “These results suggest anti-inflammatory properties of soy protein and show soy’s positive effects on obesity-related liver problems.”

The obese rats have enlarged livers compared to the lean animals and the investigators observed a significant 40 percent decrease in liver weight in the obese rats fed soy protein compared to caseinate or whey protein. Much of this reduction in liver weight was probably due to the significant decrease in liver fat in the soy fed rats. Fatty liver is a risk factor for cardiovascular disease and is seen in many people who are obese.

The researchers tried to determine how soy protein exerts its beneficial effect in the obese diabetic rats. Obesity is associated with increased inflammation, which is known to affect normal metabolic functions. Serum C-reactive protein and serum amyloid protein were lower in the soy fed obese rats compared to the caseinate and whey fed rats, indicating an effect of the soy protein to reduce inflammation in these animals. The researchers looked at specific molecular pathways of interest in the liver and fat tissue of the animals, and while they observed changes in some pathways, more work will need to be done to understand exactly how soy protein is exerting its beneficial effect in the liver.

“The findings of this study suggest there’s emerging benefits of soy protein on both inflammation and fatty liver disease,” said Elaine Krul, Ph.D., nutrition discovery lead at Solae. “This is a new area of research in regards to soy, and we’re excited to see these positive results.”

For more information on the study, the following is a link to the abstract:

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Nov 14, 2011