The Risk of Cancer and Serum Vitamin A and E and Carotenoids

To the Editor: We do not disagree with the conclusions of Willett et al., based on their excellent study (Feb. 16 issue) 1 ; however, we think that alternative explanations should be considered along with the additional investigations reported in the literature that support the role of vitamin A and beta-carotene associated wilh lower incidences of certain cancers. 2 , 3 Although serum retinol concentrations are tightly regulated within a narrow range, few data exist concerning related tissue concentrations of retinol and the retinyl esters, which probably play an important part as natural inhibitors of carcinogenesis. The administration of intermediate or high doses of . . . No extract is available for articles shorter than 400 words.