The digestive and metabolic effects of inulin (from chicory) were studied in rats adapted to semipurified diets containing 0, 5, 10 or 20% inulin (wt/wt). Moderate levels of inulin (5-10%) did not significantly affect food intake or body weight gain. Dietary inulin resulted in considerably greater cecal fermentation and a significantly greater intraluminal concentration of propionate (peaking at 58.4 mmol/L). A lower concentration of acetate (42.6 mmol/L) was observed in rats fed 20% inulin. Lactic fermentations were observed in rats fed the 10 or 20% inulin diets. The cecal pool of volatile fatty acids tended to reach a plateau in rats fed diets containing more than 10% inulin (up to 600-700 mumol), but volatile fatty acid absorption was a slightly hyperbolic function of the dietary inulin level. Butyrate absorption was proportionally lower than that of propionate. Inulin-containing diets induced an enlargement of the cecal pool of calcium, phosphate and (to a lesser extent) magnesium. There was also an enhanced absorption of these divalent cations. The cecal pool of bile acids was greater in rats fed inulin, and this oligosaccharide displayed a slight hypocholesterolemic effect, even in rats fed the 5% inulin diet. However, plasma triglycerides were depressed only in rats fed the 20% inulin diet. In conclusion, inulin seems very effective in promoting propionic fermentation and in enhancing the calcium content of the large intestine. However, high levels of inulin (greater than 10%) may affect growth in rats and lead to acidic (pH 5.65) cecal fermentation.

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 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.

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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Many countries of the world have serious problems in feeding their people, and Israel is no exception. In developing a sound programme for the food and nutrition of any country information on the composition of its home-grown foods is of particular importance. The chemical composition and nutritive value of foods produced in Palestine have been investigated by Kovacs, Guggenheim & Kligler (1939) and Guggenheim & Bichowsky (1948), but their reports are incomplete. We present here a report on the analysis of over 300 samples of fifty-four fruits and vegetables collected in Jerusalem between November 1954 and September 1956. The nutrients determined were carotene, thiamine, riboflavin, nicotinic acid, ascorbic acid, calcium, iron, sodium and potassium. Calcium and iron are the only two minerals for which specified dietary allowances are recommended and in which human diets are often deficient ((U.S.A.) National Research Council, 1953), but the importance of sodium and potassium in therapeutic diets has recently been recognized ((U.S.A.) National Research Council, Fruits and vegetables furnish considerable amounts of nutrients to the Israeli diet. During 1949-54, from 207 to 237 kg/head were consumed yearly (Lvavi, 1955). Among the vegetables, tomatoes come first, constituting from 23 to 29% of the annual vegetable consumption. Cucumbers (I I-14%) come next and then carrots (6-10%) and cabbage (6-8%). These figures compare favourably with those for other countries in the Near East. According to the Second World Food Survey (Food and Agriculture Organization of the United Nations, 1952) the annual supply of fruits and vegetables per head in 1946-9 was 124 kg in Egypt, 108 kg in Iran, IOO kg in Iraq, 207 kg in Syria and 185 kg in Turkey. '952, 1954). METHODS Samples. All samples were purchased in the open market in Jerusalem. They represent fruits and vegetables as bought by the ordinary consumer. No information as to the genetic history of the fruits and vegetables could be obtained. Most of them are, however, not truly native, but were imported during the last 60 years from Europe or the United States. Whenever possible, the samples were analysed a few hours after purchase. Some samples were stored for from I to 3 days at 2 ' before analysis.