Both the lifestyle and nutrient intake have been improving in Japan; however, it is recognized that a high energy and high fat intake can lead to possible health problems. Furthermore, the intake of vitamins and minerals still tends to be low, this having resulted in a considerable number of vitamin and mineral supplements appearing on the market and being claimed to be functional nutrients. Although the physiological functions of vitamins and minerals have been primarily established by evidence-based nutrition, the interactions of minerals and vitamins with other food factors remain unclear. This present study examines the effects of several food factors on mineral bioavailability by using animal models. In order to determine the effect of dietary egg on iron deficiency, weanling male rats were fed on a normal diet, an iron-deficient diet, and an iron-deficient diet supplemented with 5% egg powder. The hemoglobin (Hb) level was decreased, and the heart weight, hepatic copper concentration, and the activities of metallo-enzymes were increased by iron deficiency. However, the supplementation of 5% egg powder improved the effects caused by this iron deficiency. In another experiment, egg iron also improved the decrease in Fib level due to iron deficiency, this observation being similar to that with rats fed on a meat diet which contained heme iron. The level of phytate in tempeh, a fermented soy product, is reduced during the fermentation process, so the iron bioavailability of tempeh was compared with that of unfermented soybean by using iron-deficient weanling male rats. The antioxidative efficacy of tempeh was also examined. The results of this study confirmed that, compared with unfermented soybean, the fermented soybean tempeh increased the level of hepatic iron, an indicator of iron storage, without promoting lipid peroxidation in the iron-deficient rats. The level of phosphatidylcholine hydroperoxide (PCOOH) is increased in the liver of iron-deficient rats. In order to determine the antioxidative effects of dietary β-carotene and α-tocopherol, and their metabolism, weanling male rats were fed iron-deficient diets containing four different levels of β-carotene and three different levels of α-tocopherol. The increased PCOOH level due to iron deficiency was suppressed by the supplementation of β-carotene, although no dose-dependence was apparent. In contrast, the antioxidative efficacy of α-tocopherol was reduced in the liver and plasma of the iron-deficient rats. The metabolism of both β-carotene and α-tocopherol was inhibited by this iron deficiency. Fructooligosaccharides (FOS), indigestible sugars, are well known enhancers of mineral absorption by the large intestine. It was found that FOS increased the bioavailability of daidzein, a major isoflavone found in soybean, and enhanced the transformation of daidzein to equol, a more biologically active metabolite than daidzein, by stimulating the intestinal microflora in rodents. Equol may have a beneficial effect on bone loss in rodents from osteoporosis and osteonenia models. Magnesium (Mg) deficiency induces kidney calcification, bone loss and hyperlipidemia in rodents. On the other hand, hesperidin, a citrus flavonoid, regulates hepatic cholesterol synthesis by inhibiting the activity of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase. It has been reported that statins, cholesterol-lowering agents, induce bone formation and inhibit bone resorption in vitro and in vivo. Thus, the effects of hesperidin and α-glucosyl (αG) -hesperidin, which is 10, 000 times more soluble in water than hesperidin, on bone and lipid metabolism was examined in Mg-deficient rats. Hesperidin administration not only reduced the cholesterol level in the serum and liver, but also inhibited bone loss.
In order to develop appropriate methods of dietary assessment for nutritional education by the dish-based approaches, we compared the two commonly used classification methods: the 8-dish group classification (method A) which was previously reported and the 11-dish pattern determined by a cluster analysis (method B). We analyzed 577, 1, 065, and 1, 235 day meal records (totally 2, 877 days) collected from 317 women university students, and 122 and 105 of their fathers and mothers. To systematically convert the food intake data into the dish-based database, we firstly adopted method A by a database approach according to the definition and standard weight of food groups by using the software we have developed. The resulting food intake data was classified into 8 dish groups: staple foods, main dishes, side dishes, small side dishes, soups, desserts, drinks, and alcoholic beverages. We also analyzed the same food intake data to determine the pattern of dishes by method B, for which we focused on the protein, fat and carbohydrate contents, and on the amounts of vegetables, fruit and milk in each dish as variables for the statistical model. The results derived from the two methods were quite similar, 82% of the dishes included in the staple food group by method A also being classified as the V pattern (staple foods) by method B. Similarly, 63% and 30% of the dishes in the side dish group by method A were classified as X (small main dish) and IV (main dish) by method B. We conclude that the database approaches to classify the Japanese dishes for dietary assessment and nutrition education showed the universal results which may suggest the external validity of those methods.
Guava (Psidium guajava L.) has traditionally been used as a remedy for diabetes mellitus among people in the tropical and subtropical regions. To investigate the preventive effect of guava leaf tea (GLT) on the increase in blood sugar level, several studies were performed both in vitro and in vivo. An in vitro study showed some inhibitory effects of GLT on the activity of α-amylase, a group of starch-hydrolyzing enzymes. It was found that GLT markedly restrained the gastrointestinal transport and absorption of glucose in the small intestine after an oral administration of 1g of glucose to rats. GLT also suppressed the increase in blood sugar levels induced by the glucose administration. These results suggest that the inhibitory effect of GLT on the increase in blood sugar levels may be attributable to its inhibition of saccharolytic enzyme activity, as well as of the gastrointestinal transport and absorption of glucose in the small intestine.
A nationwide survey was conducted among the registered dietitians (RDs) of prefectural health centers to determine their preparedness for disasters within the municipalities they serve. The return rate was 70.2% (n=278). It was found that RDs understood details of the plans for stockpiling emergency food rations for 62.2% (707 out of 1, 137) of the municipalities under their jurisdiction. Of the 320 municipalities who had made plans for emergency stores, only 37.2% had actually established such stores. To manage the problem of budgeting for food stores, a system based on the most efficient use of resources should be created to help change the perception of such food stores. The number of locations where the most vulnerable residents of communities have not yet received advice or instruction about individual household preparedness from either prefectural or municipal health centers is in excess of 70%. Since it is unrealistic to provide administrative assistance to all individuals during a disaster, advice and instruction should be given under normal conditions to inform and educate each resident in advance of a disaster.