The effects of exercise on the metabolism and balance of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and phosphorus (P) were investigated in healthy men. An effect of exercise intensity was observed on acute changes in Na and K metabolism. The plasma renin activity and serum aldosterone level were elevated on the day of exercise, and the overall whole-body Na loss increased with increasing sweat excretion due to a lower level of decreasing urinary excretion. Acute changes in Ca, Mg and P metabolism were observed during 175 minutes of exercise. The serum parathyroid hormone level was significantly elevated, and the urinary adrenaline and noradrenaline excretion levels were also significantly increased. An overall whole-body loss was observed in Ca and Mg, but not in P. Under a dietary condition with little mineral supplementation during the exercise period, there was a significant positive shift in the Na balance, while the levels of K, Ca, Mg and P were maintained, although the possibility of overall whole-body losses was anticipated in the early days of the exercise period. However, a diet providing extra energy and increasing the intake of nutrients in proportion to energy intake level was sufficient for covering the increased excretion of these minerals in sweat; there was a significant positive shift in the Na and P balance, while the levels of K, Ca and Mg were maintained. These results suggest that a dietary regime that maintains the intake of nutrients per 1, 000kcal of energy intake would be reasonable for maintaining the nutritional status of Na, K, Ca, Mg and P under exercise conditions.
A questionnaire survey was performed on college athletes (n2=255) and students of the faculty of pharmaceutical sciences (n=346) to clarify the relationship between dietary supplements and eating behavior and attitudes. The athletes had better dietary behavior and attitudes than the students. The ratio of supplement users among the male athletes was significantly higher than that among the male students. The supply of nutrients and keeping fit and healthy were common frequent purposes of supplement use by both groups. Fatigue recovery and muscular development were also frequent purposes by the athletes. The most frequently used supplements were protein, iron and amino acids by the athletes, and multivitamins, vitamin B and vitamin C by the students. Among the male athletes, most supplement users did not have the habit of eating instant foods and snacks, and would eat even disliked foods for nutritional balance, in comparison with the non-users. Among the male students, although most supplement users understood about their poor nutritional intake, they preferred to take tablets instead of having more nutritious foods and thought of their diet only as a way of filling the stomach, in comparison with the supplement non-users. These results suggest a different relationship between dietary supplement use and eating behavior and attitudes between male athletes and male students.
The polyamine fractions extracted from soybean and natto (a fermented soybean food) were analyzed by high-performance liquid chromatography and gas chromatography. Putrescine, spermidine and spermine, as the majorcomponents, and cadaverine, homospermidine and agmatine, as a minor polyamine, were similarly detected in the whole polyamine extracts from both soybean and natto. An analysis of the polyamine extract from the glutinous surface substance of natto showed a high concentration of agmatine, this concentration increasing during the fermentation progress of natto. Agmatine was also produced in the pure cultured Bacillus natto used for natto fermentation.
The defined portion size used for foods in a semi-quantitative food frequency questionnaire (SQFFQ) survey would greatly affect the accuracy of estimating the actual intake of nutrients. The same portion size has so far been employed for both the elderly and for the general adult population. However, the portion size for the elderly is considered not always to be the same as that for the general adult population. In order to improve the accuracy of calculating the nutrient intake by the elderly in SQFFQ surveys, we investigated the ideal portion size of 84 food items for healthy elderly volunteers (23 men and 26 women) living in rural areas of Okayama Prefecture by showing them fresh samples of each food item during a 1-hour interviewer-administered survey. The portion sizes for 9 food items were within±20% of the average portion size with over 70% of the subjects, and for 45 food items with over 50% of the subjects. We found differences in portion size for rice, white bread, noodles, meat, fish, egg and other foods between the average adult and the interviewed elderly; there was a tendency toward larger portion sizes for milk, potatoes and tofu that are popularly consumed by the elderly.