Soy Peptides Demonstrate Cholesterol-Lowering Effects

Research has already shown that soybeans have an ability to help reduce levels of low-density lipoprotein (LDL, or bad) cholesterol. However, as noted in the Dec. 26 issue of the Journal of Agricultural and Food Chemistry, researchers have long attempted to pinpoint the specific cholesterol-lowering mechanism of soybeans.

However, a recent study by Korean and Swiss scientists has shown that the peptides in soybean protein hydrolysate (SPH) have a hypocholesterolemic effect. Among the mechanisms suggested, that is, blockage of bile acid and/or cholesterol absorption, inhibition of cholesterol synthesis, and stimulation of low-density lipoprotein receptor (LDL-R) transcription, note the researchers, SPH appeared to stimulate LDL-R transcription. They note that incubating soy protein hydrolysates by using the proteases from Bacillus amyloliquefaciens strongly simulated transcription. The researchers also note that the bioactivity is due to soybean peptides because the ethanol extract of soybean protein which contains isoflavones does not stimulate LDL-R transcription.

These findings led the researchers to conclude that: dietary upregulation of LDL-R transcription by soybean may be consequent to an enhanced catabolism or a reduced synthesis of intracellular cholesterol. Therefore, we suggest that soy peptides can effectively stimulate LDL-R transcription in the human liver cell line and reduce blood cholesterol level.