Alleged Effects of Vitamin

The reduction in intestinal and fecal pH following vitamin D administration caused considerable discussion in the years after it was first registered by Zucker and Matzner (1924). Beilin and Steenbock (1951) have studied anew the phenomenon on varied dietaries. They find in rats following vitamin D administration not only a reduction of the intestinal pH but concurrently an increase in the urinary pH. Steenbock et al. (1951) observed an increased output of citric acid in the urine. Sufficient acidification of the diet by the addition of ammonium chloride reduces the citric acid nearly to zero level, as would be expected. 

Steenbock et al. consider it possible that the vitamin D effects observed are secondary to the effect on calcium absorption, and that these effects would then be a secondary result of the primary action of vitamin D. It would be very interesting indeed if it could be established that vitamin D has an effect on acid-base balance, over and above what must follow from a shift of so much calcium from the intestine to the blood stream. 

An exhaustive review of this subject is not in the scope of this article. The essential features must, however, be discussed because in many studies dealing with the mode of action of vitamin D, relatively high doses of the vitamin have been administered. In such instances it is possible that what has been observed in consequence of ingestion is a mixed effect of the physiological and pharmacodynamic action. 

Pfannenstiel (1927) and Kreitmair and Moll (1928) were the first to describe the toxic effects of the newly discovered synthetic vitamin. In the ensuing years numerous publications in different countries followed and the literature grew rapidly. 

The dominant feature of the hypervitaminotic state is the dissolution of bone already formed. The ash content is reduced and the blood Ca and P are increased. When toxic doses are administered to rachitic rats, the hypertrophic cartilage becomes densely calcified, in parallel with the dissolution of already formed bone. This fact should always be borne in mind when mineral accretion in bone is studied with the aid of Ca and toxic doses of vitamin D. 

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