On the etiology of rickets / by Edward Mellanby.

  • Mellanby, Edward, Sir, 1884-1955.
Date:
[1922?]
Catalogue details

Licence: In copyright

Credit: On the etiology of rickets / by Edward Mellanby. Source: Wellcome Collection.

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    the diets used are abnormal in ways not commonly met with in the feeding of children. It is unlikely that human diets, except under rare conditions, should be so deprived of fat- soluble vitamin as are the synthetic diets of Sherman and Pappenheimer,4 and Korenchevsky,2 in their rickets experiments on rats. If this did happen, much more keratomalacia would be found among children. It has been argued by some that the fat-soluble vitamin cannot be an important element in rickets because, under experimental dietetic conditions which result in keratomalacia owing to the absence of this vitamin from the diet, rickets does not necessarily develop. This criticism seems to me to miss the point of my work, for, whereas keratomalacia appears to result from a simple defect of diet—namely, the absence of the fat-soluble vitamin—rickets is more complicated in that, so far as the bone is concerned, it is the outcome of a race between growth of bone and calcification of that bone. The antirachitic vitamin reacts with calcium and phosphorus on the diet, and thereby controls the actual calcification process, but there are other factors involved in the development of rickets, such as the amount of cereal eaten, and these additional factors make the two diseases of malnutrition under discussion largely inde¬ pendent, although one and the same dietetic factor plays an important part in the etiology of each disease. Keratomalacia is a rare disease because it is only seldom that the diet is practically devoid of fat-soluble vitamin, but, on the other hand, a relative deficiency of this substance in many articles used in the feeding of children is common, and rickets is widespread. Further, it is unlikely from a consideration of diets which produce rickets in children that the calcium and phosphorus deficiencies are of prime importance. This remark applies more particularly to the question of phosphorus, the importance of which is being so stressed in many recent publications. Although children develop rickets when the calcium content of the diet is adequate, it is true, nevertheless, as I have pointed out elsewhere, that a diet deficient in fat-soluble A is likely to be deficient also in calcium, for these substances are often closely associated in their distribution in natural foodstuffs. For instance, milk, egg yolk, and green vegetables are rich sources of each, whereas flour, rice and maize, pulses, potatoes, sugar, and jam are almost devoid of both. When, however, we consider the phos¬ phorus content of various foodstuffs and their relation to rickets, there is no evidence that phosphorus deficiency is a problem of practical importance, although the observations of Sherman and Pappenheimer4 and Shipley, Park, McCollum, and Sim- monds3 on this point may be of great scientific interest. It has been said that a combined deficiency of phosphorus and at-soluble vitamin in the diet produces more typical rickets than that produced by a deficiency of calcium and fat-soluble A. I am unable to pronounce any opinion on this point, but I have little doubt that some specific relation exists between the anti¬ rachitic vitamin and phosphorus. In 1918 I failed to obtain B