Phytic acid and the rickets-producing action of cereals

Abstract

In dogs, phytic acid (inositolhexaphosphoric acid) and neutral Na phytate from commercial phytin exerted a powerful rickets-producing action when added to a non-rachitogenic or slightly rachitogenic diet. This activity was roughly comparable with that shown by oatmeal, whose phytic acid P fraction showed the same rachitogenic action; purified neutral Na phytate nrepared from this fraction was equally potent. The rachitogenic action of Na phytate, as of cereals, is antagonised by adding extra Ca to the diet, and commercial phytin (Ca Mg phytate) is slightly antirachitic. The rachitogenic action of cereals is normally due, not to the unavailability of their P but to the action of the cereal phytic acid in inhibiting the absorption of Ca from the alimentary canal. The amt. of phytic acid in oatmeal is approximately twice that required to precipitate the Ca of the cereal at neutrality, and phytic acid exerts its rachitogenic action by preventing absorption both of the Ca of the cereal itself and of further amts. of Ca from the rest of the diet.