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Chlorosis was the first described by Lange in the 16th century as an anemia often found in adolescent girls and young women. Despite the recommendation by Sydenham in the 17th century that the condition be treated with iron supplements, chlorosis was classified among the hysterical diseases. By the end of the 19th century, the incidence of chlorosis apparently increased. It became an important subject of medical literature, but the true nature of the disease remained unknown. Many physicians believed that it was a result of a nervous disorder affecting various organ systems including the blood-forming organs. Iron medication became popular because of its therapeutic value, but its mode of action was controversial. Stockman in 1895 proposed that chlorosis was the result of a nutritional iron deficiency, but his view was largely ignored for decades. After World War I the incidence of chlorosis declined, and the disease ceased to be reported in the 1930s.

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Paracelsus (1493-1541) was a Swiss chemist and physician. As professor of medicine in Basel, he violently opposed traditional Galenic medicine and emphasized direct observation instead. His nonconformist views and rough behaviour led to his expulsion after less than a year. He led an itinerant life, practicing medicine, writing books and studying diseases of miners. Paracelcus believed in an immaterial principle, the "alchemist," that converted food into body substance. Every animal species, he believed, was endowed with its own alchemist, adapted to its needs. Paracelcus introduced chemical thinking into medicine (iatrochemistry) and nutrition. Today, he remains a controversial figure. Other Renaissance scientists (Fernel, Vesalius) criticized traditional medicine without completely rejecting it. Leonardo da Vinci developed original views on nutrition, based on his anatomical studies. His views were, however, without influence, because he did not publish.

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In 1935 Rudolf Schoenheimer (1898-1941) introduced the isotopic tracer technique in metabolic research. The results of his experiments led to a new view of metabolism and nutrition and the evolution of a concept of "continual regeneration," i.e., of continual release and uptake of substances by the cell and, thus, of a "dynamic state of body constituents." This dynamic view of metabolism can be traced back to the thinking of some investigators of the 19th and early 20th century, notably C. Bernard and F. G. Hopkins. It was Schoenheimer, however, who provided clear experimental evidence of the dynamic concept of metabolism.

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Serum 25-hydroxycholecalciferol (25[OH]D3) levels and other parameters of vitamin D nutriture were examined in 58 subjects aged 70 or more, living in Jerusalem. They were compared with those of 54 young adults living in the same neighbourhood. No evidence was obtained of a lower level of vitamin D nutriture in the elderly compared to younger adults. Serum 25 (OH)D3 of the elderly adults was 18.4 (SEM: 1.4) ng/ml and in the younger adults, 17.8 (1.0) ng/ml. There was no seasonal variation in serum 25(OH)D3, nor could a strong association be found between reported vitamin D intake nor with exposure to sunshine. There was a negative correlation between serum alkaline phosphatase and the calcium-phosphorus product in serum. High values of alkaline phosphatase were associated with reported low exposure to sunlight and, in elderly persons, with a reported low consumption of vitamin D.

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In an attempt to create a model of human infantile beriberi, pregnant rats were fed, from the 10th day of pregnancy through lactation, a low-thiamine diet. Controls were either pair-fed or offered a nutritionally complete diet ad libitum. Dams exhibited symptoms of thiamine deficiency after 30 days on the experimental diet, whereas the their pups displayed signs of thiamine deficiency from the 14th postnatal day. Brain transketolase activity was depressed in day-old thiamine-deficient pups, and brain pyruvic acid levels were elevated after the 7th postnatal day. From the 14th postnatal day, brains of thiamine-deficient pups contained less phospholipids, cerebrosides and cholesterol than those of both controls. On the 21st day, weight and lipid content of brains of thiamine-deficient and of pair-fed pups were lower than those of normal controls. In some rats rehabilitation with thiamine was begun on the 19th day, and after 23 days, brain cerebroside content was still lower in the experimental group than in both controls. Since cerebrosides are an essential component of myelin, this finding may suggest damage of the myelin sheath.

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PIP: Riboflavin excretion in relation to creatinine and the activation coefficient of erythrocyte glutathione reductase (EGR) was studied in 27 women using oral contraceptives for 2-24 months and 12 nonusers. 21 subjects took alpha-norgesterol (.25 mg) and ethinyl estradiol (.05 mg), and 6 women took norethisterone acetate (1 mg) and ethinyl estradiol (.05 mg). Neither EGR activity nor riboflavin excretion of women using oral contraceptives differed significantly from the untreated group. Riboflavin excretion of 24 women using oral contraceptives and all control subjects was acceptable or high ( 80 mcg/gm creatinine) and 25 women using oral contraceptives and 10 control subjects had an activation coefficient of 1.2, which is acceptable. This would suggest that oral contraceptives have no detrimental effect on riboflavin metabolism in women with satisfactory riboflavin nutrition.^ieng

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Nutriture of thiamine, riboflavin and folacin was assessed by two tests: thiamine (109 subjects) by the TPP effect of erythrocyte transketolase activity and urinary excretion of thiamine (mug/g creatinine); riboflavin (81 subjects) by the activation coefficient of erythrocyte glutathione reductase and excretion of riboflavin in urine (mug/g creatinine); and folacin (91 subjects) by estimation of folacin in red blood cells and in serum (ng/ml). The following correlation coefficients (r) were obtained: transketolase activity vs thiamine excretion: -0.33; glutathione reductase vs riboflavin excretion: -33; and red blood cell folacin vs serum folacin: 0.77. When "deficient" and "low" values were defined as "not acceptable" and compared with "acceptable" values, sensitivity of thiamine excretion was 54%, of riboflavin excretion 33% and of serum folacin level 90%. The respective value of specificity were 75%, 83% and 37%. Sensitivity of thiamine excretion and of serum folacin level, respectively, increased when stricter criteria of insufficiency were applied and assessment of "deficiency" of these vitamins rather than of "non-acceptability" was attempted.

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Prevalence of obesity, attitude to body weight and dimensions, eating habits, opinions on good nutrition and on the causes and prevention of obesity were studied in two groups of Israeli children, each comprising about 500 boys and girls, 13--14 years old. Mean relative weight was close to median weight for height, although 9 per cent of both boys and girls weighed more than 120 per cent of median weight. Weight was closely related to triceps skinfold thickness. Twenty-six per cent of the boys and 15 per cent of the girls rated themselves as thin, 61 per cent of children of both sexes as medium, and 13 per cent of the boys and 25 per cent of the girls as obese. Self-perception of body build was more closely related to weight than to skinfold thickness. Two-thirds of the boys and over one-half of the girls were satisfied with their weight, but dissatisfaction with size and shape was often expressed. Boys wished to have larger muscles and chest circumference and many girls, even when not obese, wanted to be smaller in size and shape. Most of the obese children wanted to lose weight. Of 499 children examined, 16 boys (7 per cent of the sample) and 58 (21 per cent) girls reported for dietary therapy. While most of these children were obese, by either subjective or objective criteria, an appreciable number of nonobese children were also dieting. The children's own perception of their body build seemed to be a strong motivation to diet for weight control. Most of the dieters did not receive any dietary advice from professional people. Over two-thirds of both boys and girls believed that daily consumption of milk, bread, fruits, eggs, cheese, meat, and tomatoes is desirable. More overweight than thin and normal-weight children indicated that, to prevent obesity, all kinds of food are permissible, but only in limited amounts. Most children believed in the fattening value of cakes, sweets, fried and fatty foods, potatoes, bread and nuts. Overweight children, particularly girls, reported eating less bread, cake and cream, adding less sugar to beverages, and eating sweets and ice cream less frequently than thin and normal-weight children. Overweight teen-agers appear to be more conscious of their food intake than under- and normal-weight children.

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Four groups of weanling rats were fed for 2 weeks on a diet sufficient or insufficient in calcium and/or phosphorus. Each group was divided into four subgroups which were offered distilled water supplemented with 0, 50, 75, or 150 ppm fluoride. High levels of fluoride in drinking water inhibited weight gain. This inhibition was less in rats deficient in phosphorus than when normal-phosphorus diets were offered. At a low level, fluoride was without any effect on bone ash, thickness of femoral cortical bone, and mechanical strength, as measured by maximal load, ultimate stress to breaking, and limit of elasticity. Modulus of elasticity was decreased. At higher levels fluoride tended to decrease most of these parameters, except in rats deprived of both calcium and phosphorus. The effect of fluoride was modified by lack of dietary calcium and/or phosphorus and appeared to be weaker in rats deficient in these nutrients. Lack of dietary calcium and/or phosphorus decreased bone strength more than did fluoride content of water and of bone mineral. Concentration of bone ash and thickness of femoral cortical bone were closely correlated with parameters of mechanical strength.

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Insulin-carbohydrate relationships were investigated in four groups of young rats fed low protein diets differing in carbohydrate and fat contents: (1) a diet in which the nonprotein energy was provided by fatty acids (FA); (2) a similar diet in which the fatty acids were substituted by neutral fat (NF); (3) FA diet supplemented with glycerol (FA-Glyc); and (4) a carbohydrate-rich diet (HC). Control rats were fed a stock diet. Rats fed the FA diet lost weight, were hypoglycemic and hypoinsulinemic in the fed state and normoglycemic and normoinsulinemic in the fasted state, and had an impaired glucose tolerance and hyperinsulinemia after a glucose load. Liver and muscle glycogen were low in fed rats. Fasting increased glycogen in liver and decreased glycogen in muscle. NF animals gained weight, were hypoglycemic in both fed and fasted states, and their plasma glucose level after an oral glucose load was almost normal. Plasma insulin/glucose ratio, both in fed and fasted states and after a glucose load indicated hyperinsulinism, which was accompanied by obesity. Muscle and liver glycogen were low in fed animals and did not change after a fast. Supplementation of the FA diet with glycerol (FA-Glyc) abolished weight loss and fasting hyperglycemia and normalized plasma glucose and insulin response to a glucose load. Rats fed the HC diet had an improved glucose tolerance and an increased sensitivity to insulin. Liver glycogen was high in the fed state and normal in the fasted state, whereas muscle glycogen was normal in both nutritional states.

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Opinions about good nutrition, causes of obesity and its prevention, as well as certain eating habits, were studied in 482 Israeli children (251 boys and 231 girls), thirteen to fourteen years old. Height, weight, and triceps skinfolds were measured. Mean relative weight and relative logarithmic skinfold thickness were close to standard, although 8 per cent of the boys and 9 per cent of the girls weighed more than 120 per cent of standard weight for their age and sex. Weight was closely associated with skinfold thickness. Over two-thirds of both boys and girls believed that daily consumption of milk, bread, fruits, eggs, cheese, meat, and tomatoes is desirable, and about two-thirds stated that overeating is a cause of obesity. More overweight than thin and normal-weight children indicated that, to prevent obesity, all kinds of food are permissible, but only in limited amounts. Most children believed in the fattening value of cakes, sweets, fried and fatty food, potatoes, bread, and nuts. The belief in the fattening value of potatoes, bread, and nuts was shared by a higher percentage of overweight than of under- and normal-weight children. Overweight children, particularly girls, reported eating less bread, cake, and cream, adding less sugar to beverages, and eating sweets and ice cream less frequently than thin and normal-weight children. A higher percentage of the obese group reported skipping one meal and eating no snack at school. Overweight teen-agers appear to be more conscious of their food intake than under- and normal-weight children.

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Four groups of rats were fed a low-calcium diet (0.02%) and two groups a normal calcium diet (0.50%). After 2 weeks one group from each dietary calcium level was sacrificed and the femurs examined. The remaining three groups which had been kept on the low-calcium diet were then given diets richer in calcium: 0.25, 0.35 and 0.5%. The remaining group on the normal calcium diet continued receiving it. After two more weeks all animals were sacrificed and their femurs examined. Rats fed the low-calcium diet lagged behind in weight gain; ash content, breaking strength, and modulus of elasticity of their femurs were much lower than those of animals on the normal calcium diet. Feeding diets with increasing calcium content increased bone ash and improved mechanical properties. However, improvement of breaking strength and elasticity did not parallel strictly increases in mineralization. Repletion with a normal calcium diet (0.50%) failed to increase bone ash to normal levels but mechanical properties were improved by repletion with substantially lower dietary calcium levels. Maximal breaking strength was obtained by repletion feeding with a dietary calcium level which failed to increase bone ash. It seems that factors other than mineralization determine breaking strength and elasticity of bone recovering from calcium deprivation.

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