Nutrition interventions improve anemic status in male college long-distance runners / 体力科学

College athletes often tend to suffer from defective nutrition status due to excessive physical training with inadequate dietary intakes, which resulted in various physical disorders such as anemia. This study was conducted to investigate the effects of nutrition interventions to the anemic state of long distance runners. A nutritional education program was applied and daily single pack of nutritional supplement drink rich in iron, zinc, copper, selenium as well as eleven vitamins were provided for two months. Blood hemoglobin, red blood cells as well as serum ferritin and iron levels after the intervention were significantly higher compared with the basal, pre-intervention level of respective items. Among the subjects, two were found to be anemic (hemoglobin<13g/dl) before the intervention. Both of them, however, were successfully recovered to normal status (hemoglobin≧13g/dl) thereafter. The pre-intervention levels of hemoglobin were negatively correlated to the amount of difference between those of pre- and post-intervention, which appeared to indicate an improvement of nutrient deficiency that caused the hypochromia. On the other hands, the intake of energy and nutrients from meals did not change before and after the intervention. From the results obtained, it seems to be appropriate to emphasize the importance of nutrition education, especially, a possible effectiveness of including multiple nutrient supplementation in nutrition program for college athletes is suggested.

NUTRITIONAL STATUS OF JAPANESE MALE COLLEGIATE ATHLETES / 体力科学

The purpose of this study was to assess the status of nutrients intake in male Japanese collegiate athletes. Each 20 of baseball (B), soccer (S), volley ball (V), and long distance (L) athletes participated in this study. The B, S, and V athletes lived by themselves, whereas the L athletes lived in an athletes dormitory with provided meal. The nutritional status was assessed for 2 days. Mean energy intakes in the B, S, V, and L groups were 43.6, 53.7, 47.0, and 55.0 kcal/kg body weight, respectively. Mean protein intakes were 1.2, 1.6, 1.3 and 2.4 g/kg, respectively. In B athletes, skipping of breakfast was recognized frequently. Most of micronutrients intakes in the B, S, and V groups were less than the recommended dietary allowances for athletes. We suggest that a provided meal system is a better system for collegiate athletes and more nutritional education is necessary for Japanese male collegiate athletes, in particular, those living by themselves.

EXERCISE DOES NOT INCREASE n-3 POLYUNSATURATED FATTY ACIDS (PUFA)-INDUCED OXIDATIVE STRESS / 体力科学

The objective of this study was to examine whether the combination of n-3 polyunsaturated fatty acids PUFA) supplementation and physical exercise training would decrease oxidative stress in comparison with n-3 PUFA supplementation only in humans. Eighteen women college students were divided into a perilla oil supplemented control group or a perilla oil supplemented physical exercise trained group throughout the experimental period of 4 weeks. After the intervention in both groups, plasma triglyceride levels were decreased. Serum thiobarbituric acid reactive substances (TBARS) level in the control group was increased by n-3 PUFA supplementation. In the trained group, however, TBARS level was unchanged. Plasma vitamin C level in the trained group was significantly decreased by n-3 PUFA supplementation. These results suggest that the combination of n-3 PUFA supplementation and physical exercise training might result in attenuated tissue damage induced by reactive oxygen species, if appropriate daily antioxidants, especially vitamin C, were provided.

EFFECT OF N-3 POLYUNSATURATED FATTY ACID SUPPLEMENTATION ON AEROBIC CAPACITY IN YOUNG WOMEN / 体力科学

N-3 polyunsaturated fatty acid supplementation has been recognized to affect the peripheral oxygen delivery system with increasing blood rheology. The purpose of the present study was to investigate whether n-3 polyunsaturated fatty acid supplementation, using purified perilla oil rich in α-linoleic acid, improves aerobic capacity in young women. Eighteen young, sedentary female college students were divided into an n-3 polyunsaturated fatty acid supplemented control group (PUFA-C, n=10) and an n-3 polyunsaturated fatty acid supplemented trained group (PUFA-T, n=8). All subjects took 20g of perilla oil (11g of n-3 polyunsaturated fatty acid) in addition to the usual diet throughout the experimental period of 4 weeks. PUFA-T subjects exercised for 30 min on a bicycle ergometer (intensity, 60% of VO₂max) 4 times a week for 4 weeks. Maximal oxygen uptake (VO₂max) and oxygen uptake at the ventilatory anaerobic threshold level (VT) significantly (p<0.05) increased after treatment in both groups. However, the endurance time in the exhaustive exercise test significantly (p<0.05) increased in the PUFA-T group only. Increasing rates of VO₂max and VT with treatment for the PUFA-C group were lower than those for the PUFA-T group (VO₂max, 12.6% vs 14.4%, VT, 9.7% vs 16.9%). After treatment, these values returned to baseline levels within 2 months of the recovery period without n-3 polyunsaturated fatty acid supplementation in both groups. Only for the PUFA-T group, VO₂max and VT at 2 months after the treatment period were significantly (p<0.05) higher compared with baseline levels. These results suggest that n-3 polyunsaturated fatty acid supplementation might have a beneficial effect on improving aerobic capacity with increasing peripheral oxygen delivery. However, n-3 polyunsaturated fatty acid supplementation was less effective than aerobic training.

Nutritional profiles in middle-aged female runners / 体力科学

Nutritional profiles in middle-aged trained and untrained women were compared both before and after menopause. Subjects were assigned to one of four groups : (1) pre-menopausal trained (Pre-T: n=14, aged 43±5 years, running distance 56±27 km/week, Vo<SUB>2</SUB>max 49±4m<I>l</I>/ kg/min, mean±SD), (2) pre-menopausal untrained (Pre-UT: n=25, 42±5 years, 34±5 m<I>l</I>/kg/ min), (3) post-menopausal trained (Post-T: n=19, 53±3 years, 49±17 km/week, 42±6 m<I>l</I>/ kg/min), (4) post-menopausal untrained (Post-UT: n=26, 54±3 years, 31±3 ml/kg/min) . There were no significant differences in hematocrit (range 38.7 to 39.3%), hemoglobin (12.8 to 13.1 g/d<I>l</I>) and total protein (6.9 to 7.1 g/d<I>l</I>) among the four groups. Serum iron concentrations in the post-menopausal women (Post-T: 97±30μg/d<I>l</I>, Post-UT: 106±29μg/d<I>l</I>) were relatively higher than in the pre-menopausals (Pre-T: 85±35 pg/d<I>l</I>, Pre-UT: 78±33 pg/d<I>l</I>) . Mean total iron binding capacity in Post-UT (326 pg/d<I>l</I>) was lower than other groups (352 to 361 pg/d<I>l</I>) . Higher serum ferritin levels were observed in the post-menopausal women (Post-T : 35.8±27.5 ng/m<I>l</I>, Post-UT : 60.4±47.1 ng/m<I>l</I>) than the pre-menopausals (Pre-T: 18.3±13.1 ng/m<I>l</I>, Pre-UT: 16.6±10.7ng/m<I>l</I>) . Intake levels of the four groups with regard to the major nutrients were sufficient as compared with the recommended dietary allowance appropriate for age, sex and physical activity level. Intakes of calcium, iron and vitamins B<SUB>1</SUB>, B<SUB>2</SUB> and niacin were higher in the trained groups than in the untrained. Regularly performed endurance exercise resulted in higher protein and iron intakes associated with higher energy intakes both before and after menopause. These results suggest that nutritional status of middle-aged women who regularly perform vigorous endurance running could be adequate for maintaining their health in a good state.

Effects of different types of physical training on insulin action in human peripheral tissues. Use of the euglycemic clamp technique / 体力科学

Physical training has been shown to improve glucose tolerance and insulin action in peripheral tissues. In the present study, regular (R) and high (H) -dose euglycemic clamp procedures were performed to determine the effects of different types of physical training on insulin action (sensitivity/responsiveness) in 10 long-distance runners (LR), 10 weight-lifters (WL) and 12 healthy controls (HC), The amount of infused glucose (glucose metabolism, GM) during euglycemic clamping is a measure of the peripheral tissue sensitivity and/or responsiveness to insulin. For R clamping, when GM was calculated per unit body weight (BW), GM in LR (11.92±1.22 mg/kg BW·min) and WL (9.28±0.63 mg/kg BW·min) was significantly (P<0.05) higher than that in HC (7.44±0.39 mg/kg BW·min) . When calculated per unit lean body mass (LBM), LR (15.07±1.56 mg/kg LBM·min) differed from HC (9, 15±0.59 mg/kg LBM·min, P<0.05), whereas the value in WL (11.50±0.93mg/kg LBM·min) was identical to that in HC. For H clamping, there was no significant change in these three groups when GM was calculated per unit BW or LBM. These results suggest that enhancement of insulin action by physical training is due to an increase in insulin sensitivity, rather than to an increase in insulin responsiveness, and that aerobic exercise, for example long-distance running, is more effective for the improvement of decreased sensitivity to insulin, which is observed in patients with simple obesity and diabetes, than anaerobic exercise such as weight-lifting.

Nutritional status of older endurance athletes / 体力科学

This study was designed to evaluate nutritional status of older endurance runners (age ; 62.5±2.5 yr., weight ; 53.8±4.2 kg, %fat ; 12.0±2.1%, mean±SD) by comparing with agematched sedentary individuals (63.6±3.5 yr., 58.4±9.1 kg, 15.6±4.0%) and middle-aged long distance runners (35.2±3.1 yr., 61.2±5.6 kg, 11.8±1.9%) . Average training distance of the older runners was a half of that of the middle-aged runners (44 vs. 85 km/week) . Maximal oxygen uptake in the older runners was significantly higher than in the older sedentary controls, but lower than in the middle-aged runners (50.4±4.1 vs. 30.6±3.5 vs. 64.0±2.2 ml/kg/min, respectively) . No differences were observed in the concentrations of serum albumin, serum iron and blood hemoglobin among the three groups. Intake levels of the three groups with regard to the major nutrients were sufficient as compared with the recommended dietary allowance appropriate for age, sex and physical activity level. Total caloric intake in the older runners was not remarkably higher than in the older controls in terms of kcal/day (2, 430 vs. 2, 230), but was significantly higher in terms of kcal/kg wt/day (45.5 vs. 38.9) . Percents to the total caloric intake of protein (15.2%), fat (25.4%) and carbohydrate (52.6%) in the older runners were almost identical to the other two groups. Ratios of animal to total in protein and fat were not significantly different among the groups. The intakes of calcium, iron, and vitamins A, B1, B2 and niacin were higher, but statistically not significant, in the older runners than in the older controls. These results suggest that nutritional status of older endurance runners is adequate for maintaining their health in a good state while keeping their active lifestyle.