Consuming soy protein could help prevent diabetes sufferers developing fatty liver, or hepatic steatosis, say researchers in a new animal study.
Hepatic steatosis is an incurable and possibly fatal condition that can accompany diabetes. It occurs when high levels of insulin and insulin resistance lead to an increase in fatty acid production, causing the liver to become enlarged.
Previous research has indicated that a soy protein diet decreases lipid accumulation in the liver by preventing the overexpression of a hepatic sterol-regulatory element binding protein.
For the new study, conducted at the Instituto Nacional de Ciencias Médicas y Nutrición in Mexico and published in the Journal of Lipid Research, the researchers set out to investigate whether it may also regulate the transcription factors involved in lipid metabolism, and thus prevent the development of fatty liver.
For 160 days they fed soy protein to a group of rats with a predisposition to become hyperinsulinemic and hyperleptinemic. A second group of rats was fed casein over the same period.
Even though the rats still became obese and developed hyperinsulinemia, the soy protein was found to prevent triglycerides and cholesterol accumulating in the liver. The same effect was not seen in the rats on the casein diet.
Lead researcher Dr Nimbe Torres explained the observation as "due to a low expression of genes involved in the synthesis of fatty acids and triglycerides in the liver."
"These changes were due to a reduction in the transcription factors that control the expression of genes involved in lipid production," she said.
What is more, the soy-rich diet was also seen to increase the breakdown of fatty acids in the liver, thanks to an increase in the levels of a transcription factor that controls genes responsible for this action.
Although further research is needed on the subject, particularly insofar as it relates to humans, the researchers believe that their results indicate that consumption of soy protein could reduce insulin resistance, renal damage and fatty liver, thereby improving the quality of life of diabetes sufferers.