The Effect of Certain Fats and Unsaturated Fatty Acids Upon the Utilization of Carotene

Abstract

Various natural oils were fed to vitamin A-deficient rats receiving controlled levels of carotene. Of the oils tested, soybean oil gave the best growth. Cottonseed oil, linseed oil, corn oil, and wheat germ oil also had a beneficial effect upon the growth. Butterfat and coconut oil had no appreciable effect. Tests with methyl linolate and methyl linolenate revealed an antagonistic action when fed with low levels of carotene. When sufficient carotene was fed with the methyl linolate, this antagonism was overcome and the methyl linolate gave a definite growth stimulation. This antagonism was counteracted at the low level of carotene intake by the addition of soybean oil and also by feeding the carotene and methyl linolate a few hours apart. Carotene analyses of the feces of the rats showed that the differences in the growth response to various oils and methyl linolate could not be explained on the basis of differences in the effect of the oils on the absorption of carotene.