Salacia reticulata is a plant widely known in Sri Lanka to be effective for the prevention of hyperglycemia. It has been shown that an aqueous extract from the stem of Salacia reticulata (SRE) has an inhibitory effect on alpha glucosidase activity and can thereby suppress postprandial hyperglycemia in humans. In this study, a placebo-controlled, cross-over trial was performed to evaluate the clinical usefulness of SRE for prevention or treatment of type 2 diabetes. The study subjects were 20 individuals (10 males and 10 females, average age 58.0±15.5yr) with type 2 diabetes. All revealed fasting hyperglycemia but were not on drug therapy. The subjects were divided into two groups, each of which was kept for six weeks on a SRE-containing diet (240mg/day) and a control-diet (placebo), respectively. After 6 weeks, the groups were crossed over, and another set of examinations was performed. Blood samples were obtained for laboratory examination before and after each set. The results indicated that the SRE-containing diet group achieved significant reductions in fasting plasma glucose levels, HbA_1C and BMI. In contrast, no changes were observed in the control-diet group. During the trial, no severe side effects of the diet were observed in either group. Thus our present findings suggest the usefulness of a SRE diet for the health care of individuals with mild type 2 diabetes.

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Recently, attention has been focused on the preventive effects of biologically active substances in marine products on life-style-related diseases, including obesity, and the mechanisms responsible have been discussed. Histamine is a derivative of histidine, and histidine is enriched in tuna and bonito. It has been reported that histamine has a suppressive effect on food intake by activating histaminergic neurons. Here, we studied the suppressive effects of orally administered histidine-enriched protein on food intake. The actual intakes of energy, protein, and histidine in 64 male and female students living in Ehime Prefecture were investigated. Under low energy intake, there was a positive correlation between the intakes of energy and protein. However, a negative correlation was seen between the intakes of energy and histidine/protein. These results suggest that histidine is converted to histamine in the human body and exerts a suppressive effect on food intake by activating histaminergic neurons.

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We examined the association between the number of food items bought in convenience stores and nutrient and food-group intakes in 1, 813 18-year-old first-year female college students taking 22 dietetic courses. The number of food items bought and the dietary habits during a one-month period were assessed with a short questionnaire and a self-administered diet history questionnaire, respectively. Intakes of energy (Spearman rank correlation coefficient, r=0.25, p<0.001) and carotene (r=0.07, p<0.01) were positively and negatively correlated, respectively, with the number of food items. Crude fat intake increased along with the number of food items (r=0.23, p<0.001), but the energy-adjusted value did not correlate significantly with the number of food items. The energy-adjusted intakes of carotene, protein, calcium, dietary fiber, iron, potassium, vitamin C, cholesterol, and n-3 polyunsaturated fatty acids showed a negative correlation (r=-0.20--0.09, p<0.001). A positive and negative correlation of confectionery items and green-yellow vegetables, respectively, was strengthened by energy adjustment (r=0.16 and-0.19 respectively, p<0.001). The number of food items was also significantly correlated with residential region, local population size, and living conditions within the students' families (p<0.05). However, adjustment for these factors did not materially alter the results.

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To clarify the effects of capsaicin on obese rats, 6-week-old and 44-week-old male Wistar rats were each separated into 4 groups. One group was given a commercial flour diet for 8 weeks (control diet group). The second group was given the commercial flour diet for 4 weeks, followed by the same diet supplemented with 0.021% capsaicin (control+capsaicin diet group). The third group was given the commercial flour diet supplemented with 16.3% lard for 4 weeks, followed by the commercial diet (high-fat diet group). The fourth group was given the commercial diet supplemented with 16.3% lard for 4 weeks, followed by the commercial diet supplemented with 0.021% capsaicin (high-fat+capsaicin diet group). Body weight, plasma triglycerides, glucose, total cholesterol, and free fatty acid levels, and the brain epinephrine level, were measured at the end of the diet period. The results were as follows: 1) The body weight of the rats fed capsaicin decreased, the decrease being greater in the high fat group than in the control group. 2) The decrease of body weight in rats fed capsaicin was greater in older than in younger rats. 3) In the rats fed capsaicin, the plasma triglyceride concentration was decreased and the glucose concentration was increased; the brain epinephrine level was also increased. 4) The body weight of older rats fed capsaicin was more decreased than that of younger rats fed capsaicin. The effects of capsaicin on triglyceride and total cholesterol levels were significantly more marked in younger than in older rats.

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