Poster Topical Area: Nutritional Microbiology
Poster Board Number: 247
Objectives: Gut microbiome research can elucidate key biological pathways underlying the dietary etiology of chronic diseases. Several studies have shown probiotic supplementation and dietary fiber intake to improve LDL cholesterol (LDL-C). Thus, we hypothesized that probiotic consumption and fiber-metabolizing microbes found in the human gut would be associated with lower LDL-C in the Men's Lifestyle Validation Study (MLVS).
Methods: The MLVS included 671 healthy men (mean age=69±6 years). We collected stool samples from a subset of MLVS to measure gut microbial features (taxonomic and functional profiling) with shotgun metagenomic sequencing. Concurrent fasting blood samples were used to assess triglyceride, LDL-C, and HDL-C levels. Pre-specified microbes included 13 probiotic species (all probiotics found in commercially available yogurt in the US) and 10 fiber-metabolizing species (microbes responsive to fiber supplementation in a review of experimental studies). We used multivariable linear regression to examine associations of species relative abundances with lipid parameters, adjusting for multiple testing.
Results: At baseline (n=233), mean LDL-C was 108 mg/dL, mean HDL-C was 55 mg/dL, and mean triglycerides were 100 mg/dL. Men with higher HDL-C levels were leaner than men with lower HDL-C levels; the opposite trend was seen for triglycerides. Species richness (total number of species) tended to decrease with increasing LDL-C (p trend=0.06). We found inverse associations of the relative abundances of three probiotic species with LDL-C (Lactobacillus rhamnosus, L. delbrueckii, Bifidobacterium bifidum; corrected p values≤0.04). Associations of L. rhamnosus and L. delbrueckii were positive with triglyceride levels (corrected p values≤0.03). Lastly, Faecalibacterium prausnitzii, a fiber-metabolizing species, was inversely associated with triglyceride levels (corrected p value=0.04). We observed no additional associations in a hypothesis-free analysis with the remaining species.
Conclusions: Relative abundances of several probiotic species were inversely associated with LDL-C levels, in line with experimental studies that have found beneficial effects of probiotics on LDL-C. Future studies should replicate these findings in diverse populations.
Funding Source: This work was supported by funding from STARR Cancer Consortium Award #I7-A714 to CH. Components of the Men's Lifestyle Validation Study were supported by NCI U01CA152904 and UM1 CA167552. AS is supported by American Heart Association Grant #16POST29660000. KLI is supported by a National Health and Medical Research Council early career fellowship.
Postdoctoral research fellow
Harvard T. H. Chan School of Public Health