Vitamin B7, Biotin, is primarily involved in utilization of macronutrients.

Biotin deficiency is very rare. The biotin adequate intake for all adults is 30 mg a day.

Biotin in food is bound to proteins. Microbiota of large intestine synthesize amounts of biotin estimated to be similar to the amount taken in the diet, and a significant portion of this biotin exists in protein-unbound form. Human epithelial cells of the colon can uptake biotin.