A study was done to evaluate the effects of two common Japanese diets, a fish-based diet and a beef-based diet, with a low linoleic acid (LA) content, on the fatty acid composition of both plasma and the erythrocyte membrane. Twelve healthy young adult female volunteers were divided into Group A (n=6) and Group B (n=6). Group A was first given the experimental fish diet (FD) for 5 days, followed by the beef diet (BD) for 5 days. The order was reversed for Group B. Blood samples were taken from each subject following an overnight fast on days 0, 5 and 10. The levels of plasma eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) did not change during the experimental BD period. However, a significant increase was observed during the period of FD ingestion. In contrast, the level of plasma LA decreased during the FD ingestion period, whereas no change was apparent during the BD ingestion period, despite low LA intake. The pattern of the change in the plasma fatty acid composition in Group A on day 5 was similar to that in Group B on day 10. However, despite the difference in the lipid composition of the respective diets, the fatty acid composition of the erythrocyte membrane did not differ between the groups on either day 5 or day 10. These results suggest that the plasma fatty acid composition is directly affected by the composition of ingested lipid within a short period of time. However, the fatty acid composition of the erythrocyte membrane appears to be affected more by low LA intake than by lipid composition during a short period of ingestion.

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The effect of Auricularia auricula-judae Quel. in ameliorating the symptoms of diabetes was investigated in rats with streptozotocin-induced diabetes. Rats were made diabetic by injection of 80mg/kg streptozotocin into 2-day-old neonates. From 9 weeks of age, the diabetic rats were given the fruit bodies of A. auricula-judge (Jew's-ear in English, and Kikurage in Japanese) as a dietary admixture at 5% food weight for 8 weeks. The fasting plasma glucose concentration, glucose tolerance, postprandial plasma glucose level and insulin secretion in diabetic rats fed the fruit bodies of A. auricula-judae were significantly improved to normal values without any effect on food intake, water intake, or body weight gain. These results suggest that A. auricula-judae contains some bioactive substances that can ameliorate the symptoms of diabetes.

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Heating conditions are very important and critical for the processing of soymilk and tofu. Microwave heating of soy slurry, i.e. “go”, was applied for the first time in this study for the preparation of soymilk and tofu. A higher protein concentration in soymilk was obtained by this method than by conventional methods of heating such as the use of boiling water. Microwave oven heating of soy slurry, which was effective for protein extraction, also made the prepared tofu more digestible by trypsin, in spite of the fact that the trypsin inhibitor activity in the tofu was higher than that in tofu prepared by conventional heating. These differences are presumed to be derived from the different modes of motion of the protein molecules induced by the different heating methods.

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