Effects of short-term, high-dose cocoa-derived flavanol supplementation on gut microbiota composition: secondary findings from a randomized, double-blind, placebo-controlled crossover study

Cocoa-derived flavanols (CDF) may act as prebiotics. However, evidence is inconsistent, and the duration and dose of CDF intake needed to elicit any prebiotic effect are undefined. This randomized, double-blind, crossover study determined the effects of short-term, high-dose dietary supplementation with CDF versus matched placebo on gut microbiota composition in 8 healthy adults. A single faecal sample was collected 8 d after supplementation with 900 mg/d CDF or placebo. Gut microbiota composition and Bifidobacterium spp. and Lactobacillus spp. abundance were measured as secondary outcomes by 16S ribosomal ribonucleic acid (rRNA) amplicon sequencing and quantitative polymerase chain reaction, respectively. No between-treatment differences in the relative or absolute abundance of Bifidobacterium spp. (Cohen's d = 0.89, P = 0.22) or Lactobacillus spp. (Cohen's d = 0.42, P = 0.65) were detected. Shannon diversity (Cohen's d = 0.38, P = 0.04) and overall community richness (Cohen's d = 0.34, P = 0.06) were lower following CDF supplementation versus placebo, but no between-treatment differences in beta-diversity or taxa relative abundances were observed. Findings are not consistent with a clear prebiotic effect of this short-term, high-dose CDF supplementation strategy relative to placebo.