vitamin precursor; a substance that is converted into a vitamin in animal tissues
provitamin详细解释
pro.vi.ta.min n.（名词）A vitamin precursor that the body converts to its active form through normal metabolic processes. Carotene, for example, is a provitamin of vitamin A.维生素原：一种由身体通过正常新陈代谢过程，将其转化成活跃形式的维生素的前体，比如，胡萝卜素是维生素A的维生素原
