The effects of diets containing raw soya-bean flour on the vitamin B 12 status of rats.

Abstract

1. There were statistically-significant relationships between the concentrations of vitamin B12 in the livers of rats and their urinary excretion of methylmalonic acid, both before and after the intraperitoneal injection of sodium propionate.2. The effects of diets based on raw and heated soya-bean flour (SBF) on the growth rates, urinary excretion of methylmalonate and hepatic vitamin B12 were compared in normal and vitamin B12-depleted rats.3. When female weanling vitamin B12-deficient rats were put on to the raw SBF diet they lost weight and became moribund after 3 weeks, even when the diet was supplemented with vitamin B12. Male adult vitamin B12-deficient rats lost weight but showed no other signs of severe vitamin B12 deficiency.4. Stock weanling male rats were fed on raw SBF diets with or without added vitamin B12. The diets were given alone and supplemented with either methionine or a mixture of methionine, valine, threonine and tyrosine. The rats still did not grow as well as those fed on diets containing heated SBF. However, there was some evidence of increased methylmalonate excretion and lower hepatic concentrations of vitamin B12 in the rats fed on the raw SBF diets.