There was an inverse correlation between the plasma homocysteine concentration and dietary protein level or protein intake when a soybean protein isolate (SPI) was used as a protein source for rats. The hepatic cystathionine β-synthase activity increased in response to the dietary SPI level. The results suggest that a high-protein diet might be an effective means to lower the plasma homocysteine concentration, probably through enhancement of the homocysteine-metabolizing activity.
