Modulation of inflammatory gene transcription after long-term coffee consumption

Abstract Scope Obesity has been found to be associated with low grade inflammation accompanied by chronic oxidative stress. The transcription factor Nrf2 is likely involved in lipid metabolism and inflammation processes, possibly mediated by an antioxidant response element (ARE)-similar region located in the promoter of lipogenic genes like peroxisome-proliferator activated receptor γ (PPARγ) and pro-inflammatory interleukin 6 (IL6). The present study investigates the influence of coffee consumption on the transcription of obesity-associated genes in human peripheral blood lymphocytes (PBL). Two different coffee blends with comparable caffeine concentrations were provided, rich either in chlorogenic acids and trigonelline (market blend, MB) or in N -methylpyridinium (NMP, study blend, SB). Methods and results In a cross-over randomized double blind intervention study 84 volunteers (male and female, 25.6 ± 5.8 years, BMI 22.9 ± 1.9 kg/m 2 , healthy, nonsmokers, regular coffee drinker) daily consumed 750 mL of the respective coffee over a period of 4 weeks, respectively. Transcription of IL6 in PBL was found to be positively associated with body fat. In the first intervention period consumption of MB decreased significantly the transcription of Nrf2, PPARγ and IL6 while concomitantly an enhanced level of PPARα mRNA was found. Due to carry-over effects for Nrf2 and PPARα, data of both intervention periods could only be pooled for PPARγ and IL6. Pooled data from both intervention periods showed a significant decrease of IL6 transcripts for SB consumption only. The changes in gene transcription appear to correlate with the level of different CGA metabolites in the plasma of the volunteers. Initial results further indicate a potential contribution of genetic polymorphisms in the nrf2 promoter and the pparγ -gene to the influence of coffee consumption on PPARγ transcription. Conclusion Regular coffee consumption affects the transcription of genes associated with obesity and/or inflammation. Metabolites of chlorogenic acids as well as genetic polymorphisms may be relevant influencing factors.