A NUTRITIONAL COMPARISON OF RAPESEED OIL AND SOYBEAN OIL

Abstract

Rapeseed oil was fed to rats at a level as high as 73% of the calories (48% by weight) of the diet, and there was no mortality in 7 weeks. This is in contrast to a report by an earlier investigator that there was complete mortality in an average of 17 days. The animals survived because the oil was gelatinized with ethyl cellulose before it was mixed into the diet, to prevent settling of the solid ingredients. When the fat levels were high, animals on the diets with rapeseed oil consumed less food and grew less than those on comparable diets with soybean oil. On the basis of caloric efficiency and ability to support growth, however, rapeseed oil was essentially equivalent to soybean oil. Thus the earlier report of the toxicity of rapeseed oil is attributable to the unpalatable form in which it was fed, and not to the oil itself. Levels of cholesterol in the blood and liver were similar whether the rats consumed diets containing rapeseed oil or soybean oil, whereas the adrenal cholesterol was increased when rapeseed oil was fed.