Effects of coffee on inflammatory cytokine gene expression in mice fed high-fat diets.

In order to investigate the risk-reducing effects of coffee in metabolic syndrome, we performed a study in mice fed a high-fat diet with added coffee and analyzed gene expression in liver and adipose tissues using cDNA microarray. Male C57BL/6J mice were raised for 8 weeks on either a normal diet (N group), a high-fat diet (HF group), or a high-fat diet with 1.1% decaffeinated (HF+DC group) or 1.1% caffeine-containing instant coffee (HF+CC group). The body weights of mice in the HF+DC and HF+CC groups were mostly intermediate between the N and HF groups, even if there were no difference in the amount of diet consumption in each group. Mesenteric fat weight was lower in the HF+DC group than in the HF group (p < 0.05) and tended to become lower in the HF+CC group than in the HF group. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were significantly lower in the HF+DC and HF+CC groups than in the HF group (p < 0.05). Inflammatory cytokine interleukin (IL)-1beta gene expression in liver was up-regulated in the HF group and significantly down-regulated in the HF+DC and HF+CC groups (p < 0.01), while MCP-1 gene expression in white adipose tissue was also significantly suppressed in the HF+DC group (p < 0.01). The induction of these anti-inflammatory responses by coffee consumption may contribute to reducing the risks of metabolic syndrome.