Experimental rickets : the effect of cereals and their interaction with other factors of diet and environment in producing rickets / by Edward Mellanby.

Edward Mellanby

Date:: 1925

Credit: Experimental rickets : the effect of cereals and their interaction with other factors of diet and environment in producing rickets / by Edward Mellanby. Source: Wellcome Collection.

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$phosphorus producing a greater defect in the deposition of calcium and phosphorus in bone than one containing less of these el<The same conclusion is reached when it is remembered that doubling the cereal in the diet, other things being constant, increases the rickets produced in experimental animals (Iable 1). Doubling the oatmeal in the diet must increase the calcium and phosphorus ingested, and therefore the absolute amount of these elements in the diet cannot be of decisive importance. It may be well to emphasize in this place, what I have previously stated elsewhere [1 g.]f that these experiments dealing with the effect of cereals demonstrate the insignificance ol phosphorus deficiency in the diet in the aetiology of rickets. Much stress has been laid by some American workers [11 and 15] on the question of phosphorus deficiency and its relation to rickets, and, even in seeking for the explanation of such conditions as starvation and sunlight on rickets, attention has been largely fixed on phosphorus metabolism. The results here described suggest that too much emphasis has been given to this aspect of the subject. But, while the absolute amounts of calcium and phosphorus in the cereals do not explain their action in interfering with bone-calcifica¬ tion, it is necessary to consider the possibility of the relati\ e amounts of these mineral elements being of importance in this respect. The point has been thought by some of the earlier observers to be ot oreat significance. For instance Ingle [25] .suggested that excess of phosphorus over calcium was responsible for the development ot * bran disease’ or ‘millers’ horse rickets’ developing in animals overfed with wheat offal. Weiske [26] found that the weight ot the skeleton and the body weight of _ rabbits were increased when calcium carbonate was added to a diet of oats, the addition o sodium acid phosphate to oats resulted in a skeleton lighter m weight than when oats alone were eaten by rabbits. I have also suggested [1 cl] that excess of phosphorus as compared with calcium mi edit explain the rickets-producing effect. of acid-caseinogen as compared with casein produced from milk by rennet, Acid- caseinogen contains no calcium but a fairly large amount o phosphorus, while casein contains some calcium as well as phos¬ phorus. It seemed possible that acid-caseinogen was more rickets- producing because its phosphorus was oxidized to phosphoric-acid, and this in its excretion deprived the body of some of its calcium. The importance of the vclat'ivc amounts of calcium and phosphorus in the diet has also been pointed out and emphasized by McCollum, Simmonds, Shipley and Park [4 b, c'J. As the result of their work on experimental rickets in rats they state that in so fai as calcium and phosphorus are concerned the physiological relation in the diet betwreen the two is of infinitely greater importance in mci easing normal calcification than the absolute amount of the salts them¬ selves ’. Sherman and Pappenheimer [16 b] have also stated that the quantitative relations of the inorganic ions are of greater importance than an absolute deficiency of any one of them. Other evidence of the importance of a balanced calcium-phosphorus$