Healthy dietary choices are associated with higher serum propionate and PGC1α expression in peripheral blood mononuclear cells in adult humans

Abstract

Obesity is a preventable multifactorial condition with negative risks to health. Gut microbiota can potentially affect host body weight through their mediators, as short-chain fatty acids (SCFAs) and lipopolysaccharide (LPS). To assess the diet-associated changes in SCFAs, LPS and related downstream mediators, peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC1α) and hypoxia-inducible factor 1 alpha (HIF1α). We hypothesized that consumed diet might be corresponding to serum levels of SCFAs and LPS and accompanied with analogous changes in their downstream effectors. Dietary intake of 31 participants was evaluated using 24-h recall, food frequency questionnaire and a Mediterranean diet scale (MDS). Serum SCFAs and LPS levels were estimated using gas chromatography-mass spectrometry and ELISA, respectively. PGC1α and HIF1α gene expression in Peripheral Blood Mononuclear Cells was detected by Real time quantitative polymerase chain reaction. Lean subjects showed higher dietary-fiber intake, MDS scores, propionate levels, PGC1α and HIF1α expression (P < 0.05). Propionate levels were positively correlated with MDS scores (P < 0.05), daily fiber intake, and PGC1α mRNA (P < 0.01). Relative expression levels of PGC1α and HIF1α were positively correlated (P < 0.05). LPS levels were higher in subjects with obesity compared to lean subjects (P < 0.01) and positively correlated with daily fat intake (P < 0.05). Subjects consuming diet closer to Mediterranean diet had higher levels of serum propionate and PGC1α mRNA. Furthermore, the up-regulated expression of PGC1α and HIF1α might work together in favoring energy expenditure and reducing body weight. • Dietary intake of study subjects was assessed by 24-h dietary recall, FFQ and a Mediterranean Diet Scale (MDS). • SCFAs and LPS were measured in serum and gene expression of PGC1α and HIF1α was assessed in PBMCs. • Lean subjects showed higher fiber intake, MDS scores, propionate levels, PGC1α and HIF1α expression and lower serum LPS. • Subjects consuming diet that is closer to Mediterranean diet had higher levels of serum propionate and PGC1α mRNA.