In this study, the properties of human saliva were analyzed in relation to subjective reports of thirst after exercise. To produce a thirsty state, subjects performed vigorous exercise using an ergometer at high temperature and low humidity. The total volume of saliva secreted, pH, and the concentrations of Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, PO₄^3- and total protein were measured. Subjective thirstiness was evaluated by a questionnaire. Under conditions of thirst, the concentrations of Na⁺, K⁺, Cl^- and total protein were significantly increased in comparison with the resting state. Buffering capacity was also increased. The amount of saliva secreted tended to be reduced, although its pH did not change significantly. After quenching of thirst by drinking mineral water, measures of subjective thirst were restored to the pre-exercise levels, but the concentrations of Na⁺, K⁺, Cl^- and total protein did not recover to their original levels.

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The relationship between the n-6/n-3 ratio in dietary fatty acids and the n-6/n-3 ratios in plasma and platelet phospholipids and whole blood aggregation were examined in 50 healthy young adult women. The range of energy intake as fat from ordinary diets in all subjects was 15-40% (average 28%), and the ratio of saturated, mono- and polyunsaturated fatty acids was 0.6-1.8: 0.9-2.1: 0.6-1.8 (average 1: 1.3: 1). The n-6/n-3 ratio of fatty acid intake was 3.3-17.8 (average 6.1±3.3), and fatty acid patterns of plasma and platelet phospholipids reflected the fatty acid composition of the diet. The whole blood aggregation pattern was correlated with n-6/n-3 ratios in the diet, plasma and platelet phospholipids. Moreover, when the n-6/ n-3 ratio in the diet was lower, the total cholesterol and triglyceride concentrations in plasma were significantly lower, but the HDL-cholesterol concentration was significantly higher.

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We produced cellooligosaccharides from cellulose with a membrane bioreactor, and studied their physiological functions. The results can be summarized as follows. (1) Although cellooligosaccharides were resistant to human salivary amylase, artificial gastric juice and porcine pancreatic amylase, they were partially hydrolyzed by rat intestinal mucosa cell homogenates. (2) The blood glucose level after cellooligosaccharide loading was gradually increased in rats. However, no increase in the blood glucose level was observed in humans. Insulin secretion was not stimulated by cellooligosaccharides in either rats or humans. (3) Excretion into feces after a single ingestion of cellooligosaccharides was not detected in rats. (4) The rats were kept for 4 weeks on a high-sucrose diet or a cellooligosaccharide-supplemented highsucrose diet. At the 4th week, body fat, the serum level of fructosamine, total cholesterol and triglyceride were higher in the high-sucrose-fed rats than in the cellooligosaccharide-fed rats. These results suggest that cellooligosaccharides are indigestible saccharides, and that they would be expected to have beneficial effects on carbohydrate metabolism and prevention of diabetes and obesity.

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We examined the enhancing effect of sesame lignans on α-tocopherol concentration in rats using three kinds of lignans: sesaminol, sesamin and sesamol. Rats were given diets for 8 weeks containing normal (50 mg/kg diet) or low (10mg/kg diet) levels of α-tocopherol supplemented with 0.2% sesame lignans. Although sesame lignans, especially sesamin, caused a significant increase in liver weight, the weights of other organs were not affected. Sesaminol and sesamin suppressed the level of lipid peroxides in the liver and kidney caused by a low α-tocopherol diet, but sesamol did not produce such strong suppression as sesaminol and sesamin. Sesame lignans increased the level of α-tocopherol in plasma and tissue. The largest enhancing effect was found with sesaminol and the smallest with sesamol. The enhancing effect was found to be more marked in rats fed a low, as compared to a normal, α-tocopherol diet.

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The inhibitory action of D-xylose on sucrase activity in vitro and its effects on elevation of blood glucose after oral administration of sucrose in vivo were examined. D-Xylose inhibited rat-intestinal sucrase activity as an uncompetitive inhibitor. This saccharide also inhibited maltase activity, but its inhibitory activity was weaker than that of a sucrase inhibitor. Among various saccharides, L-arabinose, D-ribose and D-glucurono-6.3-lactone produced inhibition to a similar extent. D-Xylose reduced the absorption of sucrose from a ligated loop in the upper portion of the rat small intestine in situ. In fact, it suppressed the intensive elevation of blood glucose and insulin levels after oral administration of sucrose in rats, and showed a similar tendency in human volunteers.

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The Rancimat method (Metrohm Co., Ltd. E 679, Herisan, Switzerland) was employed to determine the oxidative stability of olive, soybean and whale oils. The Rancimat method is based on the conductometric determination of volati le degradation products of oil heated at 120°C with aeration and automatic plotting of the conductivity against time. The evaluation is performed graphically after completion of the experiment. The order of oxidative stability of oils was olive oil (induction time I.T., 6.15h) >soybean oils (I.T., 3.03h) >whale oil (I.T., 0.87 h). The oxidative stability of oils assessed by the Rancimat method and active oxygen method (AOM test), oven test and weighing method showed a good correlation. Peroxide, anisidine, carbonyl and acid values of olive, soybean and whale oils at the rancid point (I.T.) were measured. The peroxide values were not similar among the oils. The anisidine and carbonyl values of both olive and soybean oils were almost the same, while those of whale oil were much lower. On the other hand, the acid value was highest for whale oil. From these results, it appears that the chemical characteristics of oils at the I.T. obtained by the Rancimat method are not similar among oils with different fatty acid compositions.

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A survey was conducted on about 200 female students living in seven cities: Fukuoka, Kochi, Okayama, Suita, Matsudo, Sendai and Abashiri. They were given a simple questionnaire to list the food items they consumed during three consecutive days in 1989. An average of 10.2 food items were consumed per meal and 26.3 food items per day. In each area, more than 300 food items were consumed, and the theoretical maximum number of food items was estimated to be within the range 550-620. Among the 35 mentioned food items with the highest frequencies in each area, 57 were non-overlapped food items and 16 were commonly consumed in all areas. xx²-test showed no significant differences in consumption frequencies. ABC analysis showed that food items occupying 50%, 75% and 80% of all food items numbered about 30, 75 and 90, respectively. The food items with a low intake frequency, less than 3 times in the survey, numbered more than 200, accounting for about 60% of all food items. The most frequently consumed food items were found among vegetables, fish, cereals and fruits, reflecting the corresponding number of food items in the food groups of the Japanese standard tables of food composition. There were many food items in each area not described in the standard tables. We concluded that there were no differences in food consumption patterns among the female students, despite their different environments, and that they were enjoying fairly affluent dietary habits, consuming many food items.

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