The human microbiome has no influence on metabolic processes in the human body and is only involved in immune response.

The claim is incorrect because the human microbiome actively participates in many metabolic processes, not just immune defense. Bacteria in our gut convert dietary fibers into short‑chain fatty acids that the body can use for energy and regulate blood sugar. They also synthesize vitamins such as vitamin K and some B vitamins that our cells cannot produce alone. For example, when someone consumes resistant starch, gut microbes break it into butyrate, a fuel for colon cells and a regulator of inflammation. Thus, the microbiome plays a vital role in digestion, nutrient synthesis, and energy balance, far beyond just immune interactions.