Mixed

A ketogenic diet significantly downregulates microbial amino acid and vitamin biosynthesis pathways compared to a vegan diet, likely due to higher dietary availability of these nutrients reducing host reliance on microbiome-derived metabolites.

On a ketogenic diet, your gut bacteria produce fewer amino acids and vitamins because you are getting them directly from food. This suggests that the microbiome's role shifts based on dietary intake, and you may not need to rely on gut bacteria for these nutrients as much as on a vegan diet.