The effect of restricted diets on protein metabolism was studied in obese rats (obesity had been induced by ad libitum feeding of a diet containing 30% fat and 25% casein). The obese rats were fed on one of three restricted diets, each containing 5% fat, for 2 weeks (restricted feeding groups); a high-protein diet (HPD, 50% casein), a standard-protein diet (SPD, 25% casein), or a low-protein diet (LPD, 5% casein). The food intake was restricted to 5g per day per rat. On the eleventh day, the rats were given [15N] glycine orally, and 4 days later, they were killed. The restricted feeding groups all showed similar weight losses (about 100g), 2 weeks after the start of the restricted diet. The 15N distribution in whole body was measured and results were compared with those of control rats given 5% or 30% fat diet ad libitum. The whole-body distribution of 15N in the HPD group was similar to that in the rats fed ad libitum although the diet intake was restricted. The results suggested that the amount of protein in a restricted diet is important for maintenance of protein metabolism in obese rats.
The soaked and nonsoaked rice grains were cooked by the excess water method and the steamer method, and subjected to Ranghino's test, X-ray diffraction, and microscopic observation. The starch granules in the nonsoaked rice were gelatinized at the same time as the grains became translucent during cooking. However, when the grains of medium amylose varieties and waxy rice were presoaked, the starch granules were not fully gelatinized in the translucent grains cooked for Ranghino's cooking time. The gelatinization of starch granules proceeded faster in the soaked rice and by the excess water method than that in the nonsoaked rice and by the steamer method. The cooking time and gelatinization time correlated negatively with the water content after soaking, and positively with the amylose content in the rice grains. The japonica rices were gelatinized fully in less than 20 min when the amount of water added for cooking was adequate.
Essential fatty acid (EFA) status was assessed in 15 Southern Thai preschool children. The mean (± SD) serum linoleate (18: 2 n-6), arachidonate (20:4 n-6), linolenate (18:3 n-3), eicosapentaenoate (20:5 n-3), and docosahexaenoate (22:6 n-3) percentages in the preschool children were 21.7±4.0, 6.0±1.2, 0.4±0.1, 1.2±0.8, and 4.4±1.3, respectively. Since EFA composition of total serum lipids in healthy children are not available and age and sex do not largely influence these parameters, the results of the preschool children were compared with those of 10 healthy Bangkok adults. The corresponding figures of the aforementioned fatty acids in adults were 34.9±8.5, 4.6±1.5, 0.8±0.4, 0.5±0.4, and 1.6±0.8, respectively. The data indicate linoleate and linolenate depletion in the preschool children. This was due to their low fat intake and lack of consumption of vegetable oil rich in linoleic and linolenic acids. Their high serum arachidonate percentage was probably due to the increased conversion of 18:2 n-6 to 20:4 n-6 in the presence of linolenate depletion. The significantly higher serum 20: 5 n-3 and 22:6 n-3 percentages in the preschool children should be due to direct consumption of these two n-3 fatty acids from fish intake.
The effects of dietary addition of some xenobiotics on tissue levels of copper and α-tocopherol in rats were studied with special reference to serum cholesterol. The chemicals added here were 0.05 polychlorinated biphenyls (PCB), 0.3% caffeine, 0.05% 1, 1, l-trichloro-2, 2-bis(p-chlorophenyl)ethane (DDT), 0.3% flavone, 0.3% chloretone, 0.3% 2-tert-butyl-4-methoxyphenol (BHA), 0.15% sodium Phenobarbital, 0.15% phenytoin, 0.2% sodium pentobarbital, and 0.15% phenylbutazone. Of these chemicals, dietary PCB, caffeine, DDT, flavone, chloretone, BHA and phenytoin raised the level of copper in liver, kidney, or serum. Serum a-tocopherol and cholesterol also increased with the additive or synergistic effects on these metabolisms. Moreover, these combined addition of dietary 0.02% PCB with 0.2% BHA seemed to cause additive or synergistic effects on these metabolism. Moreover, these chemicals raised serum ceruloplasmin activity. In general, serum copper, ceruloplasmin activity and a-tocopherol were correlated with serum cholesterol in these dietary manipulations.
Detection threshold for salt (NaCI) and discrimination between two levels of NaCI concentration (0.6 and 0.7%) in foods, and their relation to some selected biochemical parameters in plasma and urine (Zn, Na, K, Mg, Ca, Se for plasma and urine, Cu and retinol binding protein for plasma) were investigated in 15 healthy male college students. No subject failed to discriminate the NaCI concentrations in more than 50% of the tests. The rate of correct discrimination (RCD) was not associated with plasma Zn (P-Zn), plasma retinol binding protein (PRBP), urinary potassium (U-K) or urinary sodium (U-Na), which significantly correlated with RCD in our previous study, while the detection threshold was significantly correlated with urinary Ca-Mg ratio (UCa/Mg), urinary Ca (U-Ca), U-Na, and urinary Mg. In the stepwise multiple regression analysis, U-Ca/Mg, plasma Ca, plasma Na, and RCD were selected as significant independent variables. These indicate that the status of minerals such as Na, Ca, and Mg is related to the gustatory function. One possible explanation for the discrepancy between the present and previous results is the elevated P-Zn and P-RBP levels in the present subjects.
Vitamin E and linoleate, both of which are found in high concentrations in sunflower seed oil, were examined independently for their influence on general and blood-vascular parameters in vitamin Edeficient common marmosets. A vitamin E-deficient diet ( E, 4μg/g) was supplemented with either 40μg/g vitamin E (+E), vitamin E stripped sunflower oil (+10% SSO E), or SSO (+10% SSO w/w) in a 2×2 factorial designed experiment, and the diets fed for 9 months to 4 even groups of common marmosets. Vitamin E deficiency was associated in marmosets with a loss of skeletal muscle mass and of body weight, enhanced peroxidative haemolysis of erythrocytes, increased white blood cell counts, and in the SSO E group a relative neutrophilia. Platelet reactivity was increased with vitamin E deficiency, and to a greater degree with the SSO-E group. Aortic prostacyclin production was significantly increased by the addition of vitamin E, linoleate and both as SSO to the deficient diet, the effects being additive. Fatty acid changes associated with the different treatments reflected the influence of high linoleate and vitamin E treatments. The platelet and aortic arachidonate value in the SSO E group showed the lowest and most variable value, and this was associated with greatest platelet aggregability. An adequate vitamin E intake is essential for stabilising high PUFA diets and biomembranes and enhancing the protective role of prostacyclin in blood vessels against thrombogenesis.