Vitamin A palmitate

Vitamin A palmitate carries no histamine and releases none. It is a purified ester of retinol and palmitic acid — no protein for bacteria to decarboxylate, no live culture, no ripening step — and the quantity settles what the chemistry leaves: Rahman measured three micrograms per gram of fortified flour, Krause a median 3.3 retinol equivalents per gram of fortified sugar. Those are addition rates from two fortification programmes rather than contents of a retail product.

Vitamin A palmitate is added in micrograms, and that is the whole answer on nickel: Rahman measured fortified chapatti flour carrying 3030 micrograms of retinol equivalent as retinyl palmitate per kilogram — three micrograms per gram — and Krause found fortified sugar at a median 3.3 retinol equivalents per gram. At parts per million, whatever trace metal a fortificant brings with it arrives in a quantity no diet can register. Both figures are addition rates set by a programme rather than what a shelf product carries: Krause's own result is a shortfall, with a range reaching zero.