Research paper
Quantity and source of dietary protein influence metabolite production by gut microbiota and rectal mucosa gene expression: a randomized, parallel, double-blind trial in overweight humans.
Study answer
What this study found
High-protein supplementation altered gut microbial metabolite production and rectal mucosa gene expression, but did not change fecal water cytotoxicity or mucosal inflammatory markers. Compared with maltodextrin, both casein and soy reduced fecal butyrate; casein increased 2-methylbutyrate, while soy increased valerate, phenylacetate, tyramine, and acetoin signals. Urinary isobutyrate, indoxyl sulfate, and phenylacetylglutamine increased with protein intake, and casein specifically increased p-cresyl sulfate. Casein and soy also differentially affected rectal mucosa genes involved in mucosal…
- Study & population
- Randomized, parallel, double-blind, three-arm trial in overweight adults aged 18 to 45 years at Avicenne Hospital in Bobigny, France.
- Intervention
- After a dietary normalization run-in, participants received an isocaloric protein powder providing 15% of habitual energy intake three times daily for 3 weeks, dissolved in water.
- Key limitation
- Small active-arm sample sizes and a short 3-week intervention limit clinical interpretation.
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Open PDFOriginal abstract
Background: Although high-protein diets (HPDs) are frequently consumed for body-weight control, little is known about the consequences for gut microbiota composition and metabolic activity and for large intestine mucosal homeostasis. Moreover, the ef…