vitamin metabolic process vitamin catabolic process https://github.com/geneontology/go-ontology/issues/28908 The chemical reactions and pathways resulting in the breakdown of a vitamin, one of a number of unrelated organic substances that occur in many foods in small amounts and that are necessary in trace amounts for the normal metabolic functioning of the body, carried out by individual cells. GO:0009111 vitamin catabolism biological_process vitamin breakdown vitamin degradation small molecule catabolic process