Rancid Lard Effect on Rats Fed Complete and Riboflavin-Deficient Diets

Publisher Website
Google Scholar
Abstract
The inclusion of 10% of rancid lard in a purified rat diet led to no toxic symptoms when all known essential factors were fed separately. Five generations of rats were bred with rancid lard as the only fat source; animals receiving rancid lard were, however, roughly 5% lighter than their controls. When riboflavin was withdrawn from rats on strongly rancid lard, severe reduction of growth and food intake occurred, both symptoms disappearing when riboflavin was again supplied. A less pronounced effect as to growth retardation was observed in rats on mildly rancid lard. The differences in growth persisted in paired feeding experiments. Rancid lard, therefore, accentuated the signs of riboflavin deficiency. Preliminary experiments indicated that this effect might be due to a reduction in riboflavin available from the intestinal flora. Rancid lard seems to increase the requirements for various essential factors; this, in addition to its destructive effect on vitamins in the diet, may explain the observations that rancid lard diets lead to a fatal disease. The hypothesis is put forward that some of the non-caloric properties of normal fats are due to their ability to reduce the requirements for known and still unknown factors, in that they either supply substitutes for these factors or stimulate the production of these factors by the intestinal flora.