RELATIONSHIP BETWEEN IRON STATUS AND DAILY PROTEIN INTAKES IN FEMALE COLLEGIATE RHYTHMIC GYMNASTS / 体力科学

The present study aimed to investigate how nutritional status affected iron status, and how this knowledge might be used to prevent anemia in rhythmic gymnasts prior to a competition. We divided twenty-one subjects according to their iron status in just prior to competition into either an iron-deficiency group (n=12) and a non-iron-deficiency group (n=9), the latter of which represented the normal group. Iron-deficiency group was defined as a hemoglobin concentration below 12g/dl, a ferritin level below 12ng/ml and/or a transferrin saturation ratio under 16%. Physical, hematological, and nutritional assessments were made using a semi-quantitative food frequency questionnaire, once at 2 months before a competition, and once more just prior to the competition (‘pre-competition’).1) The iron-deficiency group had significantly lower body weight, body mass index and body fat at pre-competition compared to 2 months before the competition.2) Compared to the normal group, the iron-deficiency group had significantly lower serum iron and haptoglobin concentrations at the pre-competition.3) Intakes of energy, protein, iron, and vitamin C at the pre-competition were 1965±340kcal, 68.0±14.0g, 11.2±3.2mg, and 76±30mg in the normal group, and 1620±456kcal, 53.8±18.0g, 11.6±4.1mg, and 75±29mg in the iron-deficiency group, respectively. There was no significant difference in intakes of energy, protein, iron, and vitamin C between the groups, respectively.4) Pre-competition protein intakes per body weight (BW) were 1.46±0.33g and 1.08±0.31g in the normal group and the iron-deficiency group, respectively. Those levels were significantly lower in the iron-deficiency group than those in the normal group.5) Pre-competition protein energy ratio (13.9±1.6%) and animal protein ratio (56.0±6.7%) of the normal group were significantly higher than those measured 2 months before the competition. Conversely, those ratios remained constant for 2 months in the iron-deficiency group.6) Changes in the protein energy ratio and/or the animal protein ratio between the pre-competition and the 2 months before were significantly correlated with the pre-competition Hb levels.We conclude that the pre-competition iron status is closely associated with protein intakes in female collegiate rhythmic gymnasts.

DIETARY INTERVENTION MIGHT ENHANCE THE RBC CELL METABOLISM / 体力科学

Purpose : Rhythmic gymnasts sometimes develop severe iron-deficiency anemia. Preventing such anemia could thus enhance both their performance and health. We compared the relationship between a dietary intervention and RBC metabolism.Methods : Ten female rhythmic gymnasts were recruited for this study. Changes in the RBC delta-aminolevulinate dehydratase (δ-ALAD) activity were used as an index of biosynthesis, and changes in the haptoglobin (hp) were used to assess degradation.Results : During the one month intervention period, the athletes consumed traditional Japanese foods which provide 1500 kcal energy, 2 g/kg body weight protein, 200 g carbohydrate and 15 mg iron. No main effect of this intervention on the hematological indexes was observed. The δ-ALAD activity was significantly greater in August than in July or September. Hp concentration was significantly lower in August in comparison to the other periods.Conclusion : Dietary intervention might enhance the RBC turnover by increasing the capacity for erythrocyte biosynthesis and degradation.

Longitudinal study of annual change of bone mass at weight-bearing and non-weight-bearing sites in college women / 体力科学

To examine the relationship between sports activity and bone mass acquisition, we observed one-year changes in the bone mineral content and density (BMC and BMD) of weight-bearing and non-weight-bearing bone in 68 college women who had participated in various sports since the age of 18.5 years on average. Based on their sports experience, the subjects were divided into four groups: Group A: 18 students who have not had participated in any kind of sports activity since junior high school days ; Group B: 8 students who had participated in team sports at junior and senior high school, then stopped practicing after entering college ; Group C: 14 students who had participated in team sports since junior high school ; Group D: 28 rhythmic sports gymnasts. Whole-body and regional BMC in the head, trunk, arms and legs, and BMD of the lumbar spine and proximal femur were measured using an XR-26 DXA scanner. Height, weight and calcium intake were similar among the four groups, and during the experiment their values changed little. With regard to annual changes in BMC and BMD for weight-bearing regions: 1) In Group A, no signifi-cant increases were observed in any of the body regions; 2) In Groups B and C, only the lumbar spine showed a significant increase. Comparing the changes in BMD in these two groups, Group C showed a larger increase than Group B, although the value did not reach statistical significance ; 3) In Group D, significant increases in BMD for the lumbar spine and femoral neck and in BMC for the trunk and legs were found. The annual changes in BMD were significantly higher than Group A. As to annual changes in non-weight-bearing bones such as those in the head and arms, there were not significant differences among the groups. These data indicate that sports practice may affect changes in bone mass in weight-bearing regions in female college students. Furthermore, it is possible that the amount and quality of sports training may influence the peak bone mass and its timing.