RELATIONSHIP BETWEEN IRON STATUS AND DAILY PROTEIN INTAKES IN FEMALE COLLEGIATE RHYTHMIC GYMNASTS

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.