The rickets-producing and anti-calcifying action of phytate / by Edward Mellanby.

  • Mellanby, Edward, Sir, 1884-1955.
Date:
[1949?]
Catalogue details

Licence: In copyright

Credit: The rickets-producing and anti-calcifying action of phytate / by Edward Mellanby. Source: Wellcome Collection.

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    Examples of the relative rates of hydrolysis of phytate when oatmeal and a solution of sodium phytate respectively are boiled with 1 % HC1 are given in Text-fig. 2. The effect on the phytate of germinating oats and then mincing and leaving them to autolyse for a few days at a temperature of about 23° C, is shown in Text-fig. 3, and it will be seen that during germination hydrolysis is slow, but that during the period of autolysis following the mincing of the germinated oats there is a rapid change of the phytate to inorganic phosphate. The changes in the phytate content of oats during germination and autolysis are in line with the effects on the calcification of the teeth brought about by diets containing oats treated in these ways and referred to above (M. Mellanby). Text-fig. 3. Hydrolysis of phytate of oats during germination and autolysis. The rate of phytate hydrolysis was slow during germination but increased when the germinated grain was minced and allowed to autolyse. With this later knowledge at hand, some of the earlier experiments were repeated, and in most cases it was found that the cereal preparations with a high phytate content resulted in worse rickets than those in which this sub¬ stance had been largely converted to inorganic phosphate either by treatment with acid or by a phytase. Sometimes, however, in the later stages the animals receiving the phosphate developed the condition even more quickly than those receiving phytate, so that at the end of the experiment the degree of rickets might differ little in the two cases. These irregularities in what appeared to be closely comparable experiments were perplexing. With a view to clarifying the position, therefore, all the many earlier investigations made on the relative anti-calcifying properties of hydro¬ lysed and unhydrolysed cereals were reviewed to see what possible differences there were to account for the apparent discrepancies, and it seemed that the vitamin D reserves of the puppies at the beginning of an experiment and the length of time taken to exhaust them might be important factors. For instance,