Conjugated linoleic acid content of milk and milk products III. Biological effect of conjugated linoleic acid and milkfat; conjugated linoleic acid in the humán organism (A review)

Abstract

Based on the results of animal experiments it seems to be proved that the CLA mixed to the feed hinders the formation of gastric- and skin cancer in mice, and also the development of intestine- and breast cancer in rats. Although at in vitro experiments in the case of several human tissues the CLA significantly decreased the proliferation of the cancerous cells, it is not known how its effect is changed at in vivo circumstances. Based on some recent experiments it can be stated that the effect of the CLA on the process of carcinogenesis is very complex and it is not completely known. The required amount of CLA intake for the desirable physiological effects in human organism is not even known, we only able to give estimated values based on animal experiments. Revealing the connection between the CLA consumption and the formation of malignant tumour illnesses in human subjects encounters difficulties, since the feeding habits of volunteers taking part in the experiments should be put on record perhaps even for decades, in order to be able to compare the CLA intake with the degree of the formation of illnesses. There might be great differences in the lifestyle and environment of the volunteers taking part in the experiments opposite to the animals kept in the same experimental circumstances, so the effects of the disturbing factors could only hardly be decreased or eliminated. Despite of these difficulties, taking the results of the animal experiments into consideration, it might be expedient to carry on with the experiments on recognising the physiological effects of the CLA on humans, and for the justification of its anti-cancer effects, before we aim to increase the CLA content of food-products.