Count: 0 — No recognized vitamins start with the letter Z. This list returns zero results because accepted vitamin nomenclature includes only A, the B-complex (individual B vitamins), C, D (D2/D3), E, and K (K1/K2). Interesting detail: several important dietary substances that begin with Z — for example, zinc (an essential mineral) and zeaxanthin (an eye-protective carotenoid) — are commonly discussed with vitamins but do not meet the biochemical criteria to be classified as vitamins.

Recognize that vitamins are defined as specific organic compounds required in small amounts for normal metabolism, with distinct deficiency syndromes and biochemical roles. Authoritative bodies such as the NIH, WHO, and EFSA evaluate evidence and maintain the official lists; no compound currently qualifies for designation under the letter Z. Historical naming and the grouping of complex families (notably the B vitamins) created gaps in the alphabet, so some letters were never used.

Consider related categories instead when you look for nutrients that start with Z. Minerals like zinc, carotenoids like zeaxanthin, and other bioactive plant compounds influence health and often appear alongside vitamins in dietary guidance, but they follow different classification systems and reference-intake processes. Refer to authoritative sources (NIH Office of Dietary Supplements, WHO, EFSA) for confirmed vitamin lists and recommended intakes.