STUDIES ON THE MINERAL METABOLISM DURING PREGNANCY AND LACTATION AND ITS BEARING ON THE DISPOSITION TO RICKETS AND DENTAL CARIES

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Summary: In order to study the predisposing factors to rickets and dental caries 69 saltmetabolism experiments have been performed on 30 women living in a home for expecting mothers. The total intake and output of calcium, phosphorus and magnesium were determined for periods of 4 days during the last 2—3 months of pregnancy, in one woman from the third month of pregnancy. 17 women were given a diet used in the home for years, and which has to be considered as a quite ordinary Norwegian diet (p. 20).A negative Ca balance was found in 21 and a negative P balance in 12 of 27 experiments in pregnancy. This negative balance could be made positive or less negative by increasing the calcium to 1,6—2 gm. and for phosphorus 1,8—2 gm. daily. Table 5 p. 22. This was done partly by increasing the quantity of milk in the diet, in one case by giving calcium as a special calcium lactate preparation (Kalzan). In a few experiments an addition of cod liver oil to the usual diet without increasing the Ca intake turned the balance over in a positive direction. In the majority of experiments cod liver oil or a vitamin D preparation (Vigantol) did not affect the negative balance at all when the Ca and P intake was low. Of the 12 metabolism experiments performed during lactation on 6 women, 4 gave a negative Ca balance and 6 a negative phosphorus balance. Table 6, p. 30.The calcium content of breast milk from 14 lactating women on the same diet was found below normal, and could be increased by increasing the calcium intake in the diet. Table 9, p. 39. The P content, however, decreased in the majority of cases.Metabolism experiments performed on 7—8 months pregnant women on a diet regulated as to contain above 1,6 gm. Ca and P, a liberal amount of vitamin D as cod liver oil with fruit and vegetables giving an alkaline ash have all given a positive balance. Table 8, p. 36.When eggs were used as the source of vitamin D instead of cod liver oil by 6 women, a positive balance was also found. Table 8, p. 36.In order to study in details what effect an unregulated diet used by the first women, that is, one low in Ca, P and vitamin D, might have on the mother and youngs, some experiments on dogs were started.A bitch was given a diet low in Ca, P and vitamins A and D before and during gestation. By metabolism experiments on Ca, P and Mg performed in 3 days periods every week throughout the whole gestation, it was found that the bitch suffered a very great loss of Ca (about 10% of its original Ca content). During the lactation period 8 days after delivery, the mother animal developed tetany with a serum Ca of 5,15 mgm. and a serum P of 2,92 mgm. pr. 100cc. Chemical analyses of a metatarsal bone resected before and after gestation and lactation showed that a great loss of Ca and P had taken place in the bone resected after the end of lactation. Table 13, p. 50.X‐ray pictures taken of the newborn youngs of this experimental bitch revealed no changes from normal. Microscopical examination of these bones gave just insignificant changes. By chemical analyses however a distinct lowering was found of the calcium and phosphorus of the femur as well as of the whole body. Tables 15, 16, 17, p. 52, 54, 55. Thus we see that only by chemical analyses it was possible to demonstrate the changes taken place.The youngs which after 6 weeks of lactation were given the same diet as the mother, showed very early signs of rickets with marked deformities of the extremities. The rickets in these puppies was more pronunced and appeared earlier than in puppies born and nursed by a mother given the experimental diet from the day of delivery. These last puppies again showed a more marked rickets than puppies born and nursed by a mother on a normal ratio but given the experimental diet after weaning. Fig. 3, p. 56.Chemical analyses of the bones from these three different litters of puppies performed at the same age (112 days) showed a calcium and phosphorus and magnesium content lower than normal, a lowering which corresponded to the difference in development of ricketic symptoms. Table 18, p. 58.Microscopical sections of the same puppies showed typical ricketic changes corresponding in degree to the chemical picture. Figs. 21, 22, 23, 24, plates XII, XIII, XIV, XV.X‐ray pictures of the jaws and teeth of the puppies reveiled a similar difference in tooth calcification and development. Figs. 5, 6, 7, plates II, III. Ground specimens of teeth show the same steps in calcification of enamel as well as of dentin. Figs. 12, 13, 14, 15, plates IV, V, VI, VII.Another bitch was given the same diet as the first one just with cod liver oil added to the experimental ration which thus was deficient only in the minerals Ca and P. All steps in the experiment were repeated.The blood Ca and P showed a small lowering during gestation, no tetany developed. A similar, just smaller loss of Ca and P was found to have taken place in a metatarsal bone from this bitch as in the first one after the end of the lactation period. Table 13, p. 50.X‐ray pictures of the newborn puppies reveiled no changes from normal. Microscopical sections of the bones showed as for the puppies of the first bitch just insignificant changes. The Ca and P content of the femur as well as of the whole body showed a similar lowering as in the first experimental litter. Tables 15, 16, 17, p. 52, 54, 55.The youngs after weaning given the same diet as the mother did not show distinct ricketic symptoms, but stiffness and soreness of the hind legs, by X rays showing to be caused by multiple fractures of the long bones. Fig. 17, plate VIII.Chemical analyses of the bones from these 112 days old puppies showed a similar but smaller lowering of the Ca, P and Mg content. Table 18, p. 58.Microscopical sections of the same puppies showed mainly a picture of a bone hypoplasia (osteoporosis) with slight formation of osteoid tissue particularly for one of the puppies. See figs. 18, 27, plates IX, XVIII.The practical application of these metabolism experiments is then discussed as far as rickets and dental caries is concerned. The great difference in disposition to these two diseases in cases where the postnatal care have been alike, has been referred to an insufficient nutrition of the mother during pregnancy, which is illustrated by examples from practical life.