Dietary supplementation with conjugated linoleic acid does not improve nutritional status of tumor-bearing rats.

Tumor necrosis factor-alpha (TNF) is an immunoregulatory cytokine that plays a major role in tumor-induced anorexia and weight loss. Conjugated linoleic acids (CLA) are naturally occurring isomers of linoleic acid that, when added to the diet, improve food intake and body weight in mice injected with TNF. The purpose of the present study was to examine the effects of a diet supplemented with 0.5% CLA on the nutritional status of rats implanted with the Morris 7777 hepatoma. Body weight, food intake, serum levels of insulin-like growth factor, and splenocyte synthesis of TNF were not different in tumor-bearing animals fed CLA versus the control diet. However, insulin levels were increased in both tumor-bearing and control animals given CLA. The 0.5% CLA did not improve the nutritional status nor alter TNF synthesis in hypophagic tumor-bearing rats. The biological significance of increased insulin levels in animals given CLA remains to be determined.