For a paper appearing in Nature Communications, researchers at Sun Yat-sen University, Westlake University, and elsewhere describe distinct cardiometabolic disease relationships for microbiome-related metabolites circulating in the blood compared to those found in fecal samples. With matched gut metagenomic sequencing data, quantitative fecal metabolomic profiles, and quantitative blood metabolite patterns for 1,007 middle-age or elderly individuals from China, the team considered potential associations between cardiometabolic conditions such as nonalcoholic fatty liver disease, hypertension, or type 2 diabetes and metabolites predicted from 149 microbial species and more than 200 pathways found in participants' guts. The results point to "disparate associations with taxonomic composition and microbial pathways when using fecal or blood metabolites," the authors write, noting that their results were validated through testing on samples from another 103 adult participants. "Our results showed disparate associations with gut microbiota and cardiometabolic diseases when sing fecal or blood metabolites," they write, adding that "caution should be taken when inferring microbiome-cardiometabolic disease associations from either blood or fecal metabolome data."