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.

EFFECT OF AN INCREASED SUPPLEMENTATION OF EGG WHITE PROTEIN ON THE POST-EXERCISE LEUKOCYTE SUBSETS AND THE PLASMA IL-6 LEVELS IN MALE COLLEGIATE RUNNERS / 体力科学

This study was undertaken to compare the effect of the pre-exercise intake of a dry egg white protein supplement (86 kcal) on the post-exercise alterations in leukocytes and the plasma interleukin-6 (IL-6) concentrations in male collegiate runners. The 43 runners who participated in this study were divided into 2 groups, namely those with (E groups) and without (C groups) a 12,000 m pace run, and then they were further divided into 4 subgroups in which the subjects were given the 86 kcal nutrient supplemented including either 0, 5, 10, or 20 g protein from egg white. Peripheral blood samples were collected before supplementation (Pre), just after running (Post 0h), and at 1 h after running (Post 1h). The concentrations of the leukocytes, neutrophils, and monocytes in both groups E and C remained unchanged at Post 0 h. Furthermore, these concentrations increased significantly at Post 1 h. The lymphocytes were not significantly different at Pre. The plasma IL-6 concentrations were significantly higher at Post 0 h than at Pre or Post 1 h. In addition, no effect of the protein supplementation on the leukocytes, leukocytes subsets, or the IL-6 concentrations was observed. These observations suggested that such isocaloric supplementation as described above may therefore be able to help control the changes in the concentrations of leukocyte and leukocyte subsets immediately after running a 12,000 m time trial.

Effect of Body Iron Stores on Indices of Biosynthesis and Destruction of Red Blood Cells after a Single Session of Cycling Exercise / 体力科学

Objectives : The present study investigates the effects of body iron stores upon indices of biosynthesis and destruction of red blood cells (RBC) induced by a single session of cycling exercise.<BR>Design : Eight sedentary female students were divided into groups depending on their body iron stores : normal (C group, n=5) and iron deficient (D group, n=3) . Blood samples were collected at five time points of before (pre), immediately after (0 hours), then 1, 3 and 6 hours after exercise (248±31 kcal, 70% V0<SUB>2</SUB> peak level) . Osmotic fragility and serum haptoglobin (hp) concentration served as of for degradation, and δ-aminolevulinate dehydratase (ALAD) activity, erythropoietin concentration and number of reticulocytes served as indices of RBC biosynthesis.<BR>Results : A single session of cycling exercise did not affect the level of RBC, hemoglobin, hematocrit, serum iron, ferritin, transferrin saturation, hp and osmotic fragility in either groups. The δ-ALAD activity increased at 3 (p<0.05) and 6 hours (p<0.01) after exercise compared with that at 0 hours in the C group. In contrast, δ -ALAD activity in the D group was significantly lower at 3 hours after exercise than that of C group (p<0.001) . Reticulocytes and erythropoietin concentration increased gradually in the C group after exercise, but not in the D group.<BR>Conclusions : A single session of cycling exercise under our experimental conditions enhanced RBC biosynthesis indicated by δ -ALAD activity, whereas exercise-induced hemolysis was not evident. Body iron stores affect the δ -ALAD activity induced by a single bout of cycling exercise.