Dietary supplementation with conjugated linoleic acid does not improve nutritional status of tumor‐bearing rats*

Abstract

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.

Conjugated linoleic acid preserves gastrocnemius muscle mass in mice bearing the colon‐26 adenocarcinoma

“…In the present study, CLA did not affect growth of the colon-26 adenocarcinoma in mice. Similar findings were observed in mice inoculated with mammary tumors (Wong et al, 1997) and rats inoculated with the Morris 7777 hepatoma (McCarthy-Beckett, 2002). While it is unclear whether a diet enriched with CLA might slow tumor growth, the data from the present study suggest that the anti-cachectic effects of CLA in mice bearing the colon-26 adenocarcinoma were not secondary to suppressed tumor growth.…”

“…It is also possible that muscles of the tumor-bearing mice were more susceptible to the metabolic effects of CLA than muscles of healthy control animals. In contrast, .5% CLA given in the diet of male rats inoculated with the Morris 7777 hepatoma had no effect on total body protein compared to animals given the control diet and there was no effect of CLA on levels of TNF secreted by splenocytes stimulated ex vivo with LPS (McCarthy-Beckett, 2002). Others have noted that CLA has a greater effect on body fat and serum TNF in mice than in rats (Akahoshi et al, 2002).…”

Conjugated linoleic acid preserves muscle mass in mice bearing the Lewis lung carcinoma, but not the B16 melanoma

“…These data suggest that metabolism of AA does not play a major role in the development of SMW in mice bearing the B16 melanoma. These data are supported by others who found that .5% CLA in the diet had no effect on body weight loss in rats bearing the Morris 7777 hepatoma (McCarthy-Beckett, 2002), a tumor cell line that increased both TNFa and IL-6 in spleen cells of tumor-bearing animals (Murray, Schell, McCarthy, & Albertini, 1997). Similarly, others found that a diet containing 1.0% CLA did not improve body weight in mice bearing a mammary carcinoma (Wong et al, 1997).…”

c9t11‐Conjugated linoleic acid‐rich oil fails to attenuate wasting in colon‐26 tumor‐induced late‐stage cancer cachexia in male CD2F1 mice

“…McCarthy and Graves and McCarthy‐Beckett et al . reported that 0.5% of CLA in the diet preserved muscle mass in mice with Lewis Lung carcinoma, but had no effect in mice with B16 melanoma or in rats with Morris 7777 hepatoma 26, 45. Wong et al .…”