Cereals and rickets. The rôle of inositolhexaphosphoric acid

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Abstract
Quantitative comparison of the influence on rickets in rats (cf. preceding entry) has been made with diets containing 2% of CaCO3 and 68% of either oatmeal, maize + white flour (20:48), or maize. The oatmeal has a curative effect greater than that of maize + white flour, but less than that of maize + white flour with Na2HPO4 added to equalize the P content. Na or Ca-Mg inositolhexaphosphates have no curative effect, and the intermediate potency of oatmeal is due to the fact that a large proportion of its P is in this poorly available form. Hydrolysis of the oatmeal with HC1 converts inositolhexaphosphate into phosphate and raises the antirachitic potency to that of the maize + white flour + Na2HPO4 diet. The differences of antirachitic potency of the cereals investigated and their rachitogenic effect in high Ca diets can be completely accounted for by differences in the total P content and in the proportion of unavailable inositolhexaphosphoric acid. Preliminary expts. suggest that in low Ca-high P diets excess of inositolhexaphosphate interferes with absorption of Ca at least as effectively as excess of phosphate. Oral administration of Na inositolhexaphosphate to monkeys produced no specific nervous symptoms, and this substance is not related to the "toxamins" of cereals producing nerve degeneration.