Three-day diets were recorded (weighing method) by 39 volunteer housewives (35-62 years of age), who were participants in the adult disease prevention program promoted by a local health center located in a suburban area of Tokyo. Nutrient intakes for 22 items in the records were calculated based on Standard Tables of Food Composition in Japan (4th revised Ed., 1982), and correlation coefficients among these items were computed statistically. From the viewpoint of mineral nutrition research, an indicator of “salt-free ash” (SFA: values obtained by excluding sodium as sodium chloride from ash) was introduced in this analysis. The intakes of SFA showed strong correlations with several components including protein, potassium and iron. These results, in combination with the earlier finding that SFA was also correlated well with dietary magnesium content, may indicate the applicability of SFA as an indicator, at least for potassium, iron and magnesium, in nutritional assessment.
The selenium contents of wheat and soybean products consumed in Japan were determined byfluorometric analysis. Whole wheat and soybean samples, grown at various sites in Japan, showed low selenium values. The mean values were 0.02 (wheat, n=5) and 0.03 (soybean, n=18) μg Se/g, respectively. High selenium values (0.30 to 1.15μg Se/g) were found in imported American or Canadian hard or durum wheats. Australian wheat showed moderate selenium levels (0.07μg Se/g), and American soft wheat showed the lowest level (0.02μg Se/g). Selenium in commercial wheat products was also determined. The hard type of wheat nour, bread and Japanese spaghetti, produced from the American or Canadian hard or durum wheats, showed high selenium values (0.19 to 0.79μg Se/g). Similarly to wheat, the selenium contents of imported American soybeans were higher than those of other soybean samples. However, most commercial soybean products sold in local retail shops in Japan contained comparatively Iow seleRium levels (0.01 to 0.05μgSe/g). Based on the present results and the National Nutrition Suryey, selenium intake from wheat products by Japanese was estimated to be around 20μg/day/capita. These results indicate that wheat products produced from imported American or Canadian hard or durum wheat are a major source of selenium in the Japanese diet.