E. V. McCollum

Effects of Acute Dietary Zinc Deficiency in the Rat

By means of a diet furnishing about 7 μg of Zn per rat daily, studies at the University of Wisconsin 1-4 have convincingly demonstrated the indispensability of Zn in the nutrition of rats, although the Zn-deficient diet permitted the experimental rats to gain about 8 g per rat weekly during the 10 week period on the diet. 4 The findings have invalidated the conclusion from our laboratory 5 several years ago that the element probably is not a dietary essential. We have recently prepared a diet furnishing not more than 2 to 4 μg of Zn per rat daily. Young rats restricted to it quickly developed extreme degrees of deficiency. Because the studies have been temporarily interrupted, owing to the transfer of one of us (H.G.D.) to another laboratory, we have decided to make a preliminary report on the work at this time. Diet. The diet was : casein hydrolysate (tryptic)† 15.00, egg white (cooked) 3.00, sucrose 66.29, salts 5.71, butter fat 10.00, and Oleum Percomorphum 50%, 2 drops per 100 g diet (approximately 2800 vitamin A units and 400 vitamin D units). Each rat was given a daily supplement containing the equivalent of 6.4 g liver, 40 μg of thiamin and 1.0 mg of choline. The liver concentrate,‡ dissolved in 6 volumes of water, was centrifuged. The supernatant solution was transferred to a Pyrex glass separatory funnel and the pH was adjusted to about 6. The solution was extracted repeatedly with dithizone (diphenyl thiocarbazone) dissolved in CC14. When no more Zn could be removed Zn-free dilute HC1 was added until the pH was about 4. The excess of dithizone was removed with redistilled CC14.

The Effects of Strontium Administration on the Histological Structure of the Teeth of Rats

The effects upon the animal organism of the feeding of strontium salts has been studied by a number of workers. Stoeltzner (1908) and Lehnerdt (1910) have reported that the feeding of strontium salts results in the production of excessive amounts of osteoid tissue in the bones. Shipley, Park, McCollum, Simmonds, and Kinney (1922) reported similar findings. They used McCollums diet 2581 as a basal one, which is composed as follows:

A delicate biological test for calcium-depositing substances

Some time ago we described two diets, Nos. 2638 and 2677, which we used with a view to the development of a biological test which would show the calcium-depositing power of any given substance. 1 The test was carried out as follows: The faulty diet was first fed to a group of young rats for the purpose of making the epiphyseal cartilage free from calcium, and producing a rachitic metaphysis. After a sufficiently long period had elapsed, the test substance was added to the diet of those animals which were to serve as test subjects, while the faulty diet without the test substance was continued in the case of the control rats. Substances, which when added to the faulty diets enabled the organism to deposit lime salts, caused the reappearance of the provisional zone of calcification in the bones. This biological test we called the “line test,” because the new provisional zone of calcification appeared as a line of calcium salts extending transversely across the bone with a limeless cartilage on one side of it and a limeless metaphysis on the other. The success of this test depends on the use of a diet which uniformly causes the epiphyseal cartilage and the metaphysis to be free from calcium salts. It is not sufficient that a diet should merely produce rickets. The rickets which it produces must be of so severe a type that no vestige of calcium remains in the cartilage, and a wide metaphysis is formed. Moreover, the diet must be so constituted that the animals restricted to it will grow and maintain a fair state of general health and nutrition. The diets which we earlier described were not satisfactory, since they did not invariably produce typical rickets.

Relationship Between Diet and Dental Caries

I appreciate the opportunity of being here this evening to give such thoughts as I have on the relation of diet to dental caries. What I shall say will be mainly an interpretation of the results of animal experimentation as they relate to this subject. Not many years ago the slogan was frequently heard that a clean tooth never decays. This was given wide publicity and the promise was made that assiduous application of a tooth brush with a recommended dentifrice would insure against tooth decay. That idea has been discredited. Advice on prophylaxis through diet, as well as advice concerning how to keep the mouth clean, has frequently failed to accomplish its purpose. There are people in various parts of the world who enjoy relative freedom from tooth decay. The northwest Greenlanders exist essentially upon a carnivorous diet, consisting principally of eggs and the flesh of birds, the beluga whale and the norwal. Only for a short time during the summer do they get any fish. They get almost no land animals. They are said by Dr. Hrdlicka to have the best teeth of any fairly large group of people in the world today. They are nearly free from dental disease. On the other hand, there are people adhering strictly to a vegetarian diet, or a vegetarian diet supplemented with milk, who likewise have relatively little dental disease. I have come in contact in the last fourteen years with a considerable number of foreign students. The Hindu students, mainly medical men past thirty years of age, have in general distinctly better teeth than have Americans. A recent report on the condition of the teeth of the inhabitants of the Islands of Tristan da Cunha by Dr. Marshall affords an interesting illustration of the effect of the character of the diet on the health of the

The Significance of Food-Particle Size in the Etiology of Macroscopic Dental Decay in Rats

Introduction. Recent work by Hoppert, Webber and Canniff2 has suggested the possibility that size of food particle plays a role in the etiology of macroscopical dental decay in rats. Their animals ingested the following diet (adequate): ground yellow-corn, 60 parts; wholemilk powder, 30; linseed-oil meal, 6; alfalfa meal, 3; NaCl, 1. The rats on this diet developed dental decay in the molar teeth at eight weeks of age. Some of the ground yellow-corn was then sifted through a 60-mesh sieve. The portion that passed through the sieve (substituted for the ground whole-corn in the diet of the first group) was fed to another series of rats, which, fed for eight weeks, did not develop dental decay. The conclusion noted by these workers, namely, that size of food particle was the causative factor in the caries incidence, was not entirely justified by the experiments, for it may readily be noted that there are many differences aside from particle size between ground corn and that part of corn which passes through a 60-mesh sieve. Nevertheless, Hoppert, Webber and Canniff have, in this manner, offered an interesting suggestion, which was subjected to further investigation in the experiments described below. It should be noted that this paper is concerned only with macroscopic dental decay in rats; that is to say, with very obvious and easily identified holes in the molar teeth. The authors have already pointed

II. The prevention of the development of rickets in rats by sunlight

In June, 1919, Huldschinsky 1 reported that the ultraviolet ray exerted a curative action in rickets. The criterion on which he relied was the evidences furnished by the X-ray of calcium deposition at the ends of the long bones. He found that there were definite signs of calcium deposition after four weeks of treatment and that at the end of eight weeks healing was almost complete. In May, 1920, Huldschinsky 2 again reported the curative effects of treatment with the ultraviolet ray in rickets in a series of thirty children, aged between one and one half and six and one half years, who exhibited all clinical manifestations of the disease. In all, healing was accomplished after twenty-two to twenty-six treatments covering a period of two months. In April, 1920, Putzig 3 corroborated the findings of Huldschinsky. He obtained cures by means of the quartz lamp in premature infants suffering from rickets. In July, 1920, Riedel 1 further confirmed Huldschinskys findings in a series of one hundred children suffering from rickets. In June, 1921, Hess 2 confirmed Huldschinskys findings in a series of six cases. The favorable influence of sunlight in rickets has been recognized by some students of the disease for a long time, notably by Palm 3 (1890), and experimental evidence of its beneficial effect on mineral metabolism in the puppy has been furnished by Raczynsky 4 in 1912. Huldschinsky made use of sunlight together with the ultraviolet ray in two cases of his series and Riedel relied on treatment with sunlight in some of his cases, supplementing with the quartz lamp ray only on sunless days. Hess 5 was the first, so far as we are aware, to demonstrate, by means of the radiograph, that sunlight alone exerts the same curative action as the ultraviolet ray.

The prevention of rickets in the rat by means of radiation with the mercury vapor quartz lamp

All the evidence as to the preventive and curative effects in the rickets of human beings of the radiations from the mercury vapor quartz lamp has been furnished by the X-ray. In order to determine the protective action of these radiations in experimental rickets in rats and also to examine the bones themselves we performed the following experiments. Nineteen rats, mostly mixed black and white and about seven weeks old, were placed on diet 3143 which, as previous experience has shown, produces rickets comparable in every respect to the rickets manifesting itself in human beings. Nine rats were kept as control animals under ordinary laboratory conditions in a room completely screened with windows of ordinary glass (cage “R” animals). Ten rats were exposed to the radiation from a Hanovia mercury vapor quartz lamp (Alpine type) (cage “U-V” animals). One animal (16Y) in cage “R” was found paralyzed thirty-eight days after being placed on diet (age about eighty-eight days) and was killed. We have previously pointed out that the development of paralysis of the posterior extremities not infrequently occurs in rats fed on diet 3143. Another animal (26Y) was killed fifty-eight days after being placed on the diet (age about one hundred and eight days); and the other seven animals were killed sixty-four days after being placed on the diet (age about one hundred and fourteen days). The animals in cage “U-V” (rayed animals) were exposed to the radiations at a distance of three feet for varying periods of time daily for sixty-four days and were then killed. The rayed animals as contrasted with the control animals showed marked physical vigor as evidenced by growth, activity, good appetite, thick smooth coats and reproductive power.

Food, Nutrition, and Health

I Nutrition and Food Safety in the United States.- 1 The Search for Health: Nutritional Considerations.- Digestion and Absorption.- Recommended Dietary Allowance - The RDA.- Water.- Energy, Calories, and Weight Control.- The Macronutrients: Protein, Carbohydrate, and Fat.- Vitamins.- Minerals.- 2 Nutrients for Athletes.- Water.- Iron.- Salt.- Protein.- Recommended Diets.- Weight Loss.- Weight Gain.- Special Diets.- Self-Prescription and Its Dangers.- 3 Food Additives.- How Food Additives Are Approved.- Why Do We Use Additives in Our Food.- Amounts of Food Additives Used.- 4 Food Preservation.- Food Spoilage and Deterioration.- 5 The Road to Fitness and Health.- Exercise.- Vegetarianism.- Zen Macrobiotic Diet.- Organic and Natural Foods.- Chemophobia.- Prevention of Heart Disease by Diet.- Diet and Cancer.- Dietary Cure-Alls.- Weight Control.- Choosing a Healthy Diet.- How Good Is My Diet.- II Food Supply.- 6 Food from Cereals: The Green Revolution.- Wheat.- Rice.- Future Hope.- 7 Food from Animals.- Beef Production.- The DES Story.- Milk.- Pork.- Poultry.- Eggs.- Sheep.- Goats.- Calculation of Meat Consumption.- 8 Food from the Sea.- Unlimited Potential?.- Theoretical Production.- Fish Protein Concentrate.- Ecological Issues.- 9 Potential Sources of Protein.- Protein from Soybeans.- Protein from Petroleum.- Protein from Carbohydrates.- Protein from Leaves.- Protein from Algae.- Protein from Fungi.- Miscellaneous Sources.- 10 Improvement of Food by Nutrification.- Combinations of Foods.- Addition of Vitamins and Minerals.- Addition of Protein.- Genetic Engineering.- 11 Nutritional Labeling Impact on Nutrification.- Protein Content.- Fat Content.- Vitamins and Minerals.- Foods, Supplements, and Drugs.- The Voluntary Aspect.- The Outlook.- 12 Dietary Goals.- Nutritional Education.- Dietary Goals.- Conclusions.- 13 Food Safety.- Chemicals in the Food Supply.- The Risk-Benefit Concept.- Relationship of Animal Data to Humans.- Estimates of Benefit.- 14 Food vs. Fuel.- The Rise and Fall of Gasohol.- The Economics of Ethanol Production.- Economics of Alcohol in Gasoline.- The Proalcool Program in Brazil.- The Potential for Methanol.- Conclusions.- 15 Potential for Disaster.- Plant Diseases.- Coffee Rust.- The Changing Climate.

Studies on experimental rickets, IV. Cod liver oil as contrasted with butter fat in the protection against the effects of insufficient calcium in the diet

In our experimental work we have made observations which demonstrate in a striking way the differences in the effectiveness of cod liver oil as contrasted with butter fat in influencing the rate and extent of growth, and their effects on the histological structure of the bones. This is well illustrated by the results of restricting young rats to the following diet: This diet induces fairly good growth and fertility during at least 8 to 10 months, notwithstanding its deficiency in calcium. The calcium content of this food mixture is 0.059 gms. per 100. The optimum calcium content of this diet is reached when about 1.5 per cent. of calcium carbonate is added. The phosphorus content of this mixture is 0.3546 gms. per 100, and is not far from the optimum content. This food mixture is slightly alkaline owing to its content of sodium bicarbonate. This food mixture with butter fat to the extent of 3, 10, or 20 per cent. of the food mixture fails to induce an appreciable amount of growth. With 2 0 per cent. of butter fat the animals gain but a few grams in weight, look very inferior, become short and stocky, and are rough coated. This diet when 10 per cent. of casein is added, but without the addition of either butter fat or cod liver oil, causes pathological changes characteristic of rickep. With small amounts of cod liver oil (3 per cent.) no rachitic changes are seen in the bones. Even 20 per cent. of butter fat fails to effectively direct the growth processes in the bones toward the normal condition. They usually die within a few months. This food mixture containing 3 per cent. of butter fat and 1.5 per cent. of calcium carbonate is a highly satisfactory diet for the promotion of growth to the full adult size, the maintenance of high fertility throughout the breeding period in the females and the successful nutrition of the young by the mothers. Even a fifth

Effect of Oral and Parenteral Administration of Vitamin E on Creatinuria and Symptoms of Dystrophic Rabbits.

Conclusions The oral administration of 20 mg of α-tocopherol to dystrophic rabbits produces a rapid fall in the urinary creatine. Following the parenteral administration of the same dose, the creatine remains at a high level, and the creatinine decreases. The injection of massive doses of α-tocopherol cures dystrophy in some cases, while in others it extends life and promotes growth for several months without curing the symptoms of the disease.