On deficiency diseases, with special reference to rickets / by Edward Mellanby.
- Mellanby, Edward, Sir, 1884-1955.
- Date:
- 1924
Licence: In copyright
Credit: On deficiency diseases, with special reference to rickets / by Edward Mellanby. Source: Wellcome Collection.
3/12
![A British Medical Association Lecture ON DEFICIENCY DISEASES. WITH SPECIAL REFERENCE TO RICKETS.* Recent investigations on diet have profoundly modified our views on nutrition, so that emphasis on the impor¬ tance of quality of foodstuffs, which developed as the result of the discovery of vitamins, has now in turn been supplemented by equal emphasis of the importance of balance and interaction of dietetic elements. With the advance of knowledge the question arises as to the adequacy of the term “ deficiency diseases,” about which it is sug¬ gested I should address you this evening. The phrase is obviously only adequate, at least as regards rickets, if it be remembered that “ deficiency” is merely a relative term, and what may be an ample amount of a food factor allow¬ ing good health in one diet and under one set of conditions may be a real “ deficiency ” having dire results in other circumstances. At all points of the advance in knowledge of this new aspect of nutrition the pathological side of the subject has forced itself upon the notice of the investi¬ gator, and, speaking from both the laboratory and clinical point of view, I propose in this lecture to show how some widespread diseases are related to common dietetic faults. As regards the two earliest known and best recognized of the deficiency diseases—scurvy and beri-beri—I do not pro¬ pose to say much, because, neither from the academic nor the practical standpoint, has recently acquired knowledge of these diseases greatly modified or extended the earlier views. Although both diseases are comparatively rare as definite syndromes in this country, we still do not know to what extent they are responsible for milder conditions of ill health whose cause escapes detection. In the case of scurvy most recent work is concerned with the relative amount of antiscorbutic vitamin in different foodstuffs, and more especially in the different forms of milk, including dried milk, on the market. On the whole, as regards this latter point, the general opinion among workers is that milk dried by the roller process has a greater amount of antiscorbutic vitamin than spray-process milk. My own experience is in agreement with this view. Many practical points remain to be cleared up in connexion with scurvy, for we are still ignorant both as to the nature and mode of action of the antiscorbutic vitamin. There are, how¬ ever, but few diseases which yield so readily to treatment as does scurvy to the addition to the diet of foods rich in antiscorbutic vitamin such as oranges and lemons. The rapid disappearance of beri-beri which is reported from Japan and other parts of the world where the disease was very common, as the result of application of facts concerning the relation of this disease to vitamin B, is a triumph of which the pioneer workers on this subject, in¬ cluding among others Eijkman, Grijns, Braddon, Fraser, ii and Stanton may well feel proud. There are still, however, | some authorities who do not believe that the etiology of beri-beri is fully explained by the simple dietetic deficiency | pf vitamin B, and this view has recently been revived by McCarrison.1 The subject merits further work. Great attention has been given both by physiologists and those interested in experimental medicine to fat-soluble vitamin, or vitamins if they should ultimately prove more * Delivered before the Bradford Division of the British Medical Association, March 26th, 1924. [245/24] than one, during recent years. The reason for this interest is no doubt the feeling that deficiency of these particular substances in the diet of many people in this country is a reality, and is responsible for great defect both of bodily structure and of health. As I propose to spend most of the time this evening describing the defects for which these vitamins are responsible, as well as their mode of inter¬ action with other dietetic substances and with the environ¬ ment, it may be well to point out that intrinsically vitamin A is of no greater importance than any other element of the diet which is essential to life. Actually, however, it seems to be of greater importance to us as medical men, for a number of circumstances have assisted in bringing about a state of affairs so that a deficient intake of this vitamin has become of serious import in the national life. In the first place, the distribution of the vitamin is restricted to comparatively few foods—such as milk, eggs, green vegetables, etc.—-and these are often dear or difficult to procure. Secondly, the element calcium, in conjunction with which vitamin A works, is also defi¬ cient in the average diet. Thirdly, cereals, which are cheap and therefore form a large part of the dietary, contain some substance or substances which actively antagonize the action of the fat-soluble vitamin in some important respects. Finally, the climate of this country, and espe¬ cially the lack of sunshine, is such that we require rela¬ tively large quantities of the vitamin to bring about normal development and health. I shall now describe to you the evidence—most of it obtained by experimental work on animals—which indicates that some of the physical defects commonly seen among the people in this country can be ascribed to simple dietetic errors, whose mode of action centres round fat-soluble vitamin. After dealing with the experimental side of the subject I shall briefly sketch attempts made to apply the facts to the treatment of various clinical conditions. Fat-soluble Vitamin and the Bone Abnormalities of Biekets and, Osteoporosis. The most potent factor in the diet so far discovered which stimulates the formation of bone is vitamin A, or a substance having similar distribution and properties as vitamin A. Whether this calcifying substance, or the anti¬ rachitic vitamin as I have elsewhere called it, is identical with vitamin A—that is, the vitamin discovered by McCollum and Davis—and a substance necessary for growth of young rats and for the prevention of keratomalacia, is still uncertain. Some of the apparent differences between vitamin A and the antirachitic vitamin I have previously discussed, and other points of difference have been em¬ phasized by McCollum and his co-workers, and also by Goldblatt and Zilva. The point will not be settled until the synthetic diets used in the growth experiments and in the rickets experiments on rats are identical. In the experiments on rickets carried out by these workers the diet used has been deficient not only in the antirachitic vitamin but also in phosphorus, whereas in the growth ex¬ periments only vitamin A has been deficient. Accurate](https://iiif.wellcomecollection.org/image/b30624617_0003.jp2/full/800%2C/0/default.jpg)
