The Effect of Lean-Seafood and Non-Seafood Diets on Fecal Metabolites and Gut Microbiome: Results from a Randomized Crossover Intervention Study

Abstract

Scope: The impact of dietary protein types on the gut microbiome is scarcely studied. The aim of the present study is therefore to examine the effects of lean-seafood and non-seafood proteins on the gut microbiome composition and activity and elucidate potential associations to cardiovascular disease (CVD) risk factors. Methods: A crossover intervention study in which 20 healthy subjects consumed two diets that varied in protein source was conducted. 1H NMR spectroscopy and 16S rDNA sequencing analyses were applied to characterize fecal metabolites and gut microbiota composition, respectively. Results: A twofold increase in fecal trimethylamine excretion was observed after the lean-seafood diet period. Circulating TAG and the total to high-density lipoprotein (HDL) cholesterol ratio as well as circulating TMAO levels were each associated with specific gut bacteria. Following the non-seafood diet period, a decreased relative abundance of Clostridium cluster IV and a tendency toward an increased Firmicutes/Bacteroidetes ratio were found. Conclusions: Lean-seafood and non-seafood diets differentially modulate the gut microbiome composition and activity. Furthermore, the gut microbiota composition seems to affect circulating TMAO levels and CVD risk factors.