Articles : Dietary Intake, Hematological Parameters, GH and IGF-1 in Gymnasts Aged 9-17 Years |
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Abstract |
The purpose of the study was to examine interactions between dietary intake, hematological parameters and IGF-I in young gymnasts aged 9-17 years. Subjects included 89 gymnasts (45 boys and 44 girls) aged 9-17 years. All the gymnasts were characterized as being highly competitive and trained 5 days a week, 3.5 hours a day. Dietary intake was evaluated from three randomly assigned days of diet records, including one weekend day and two weekdays. All subjects completed a three day diet record. From these records, average daily intakes of the nutrients were estimated using Computer Aided Nutritional Analysis Program. Blood samples were drawn in the morning after a 12-h fast and were spun at 3000rpm for 5min. Hemoglobin, hematocrit, red blood cell, mean corpuscular volume, mean corpusclar homoglobin concentran, and mean corpuscular hemoglobin were analyzed by automated instrumentation (ADVIA 120, Bayer, USA). Serum iron and total iron binding capacity were determined by auto-anaylzer (HITACHI 7150, Tokyo, Japan) and transferrin saturation was calculated by dividing serum iron concentration by TIBC. The serum was separated and stored at 7000. IGF was extracted from IGFBPs using the acid-ethanol extraction method. GH (growth hormone) and Serum IGF-I concentrations were determined by a Radioimmunoassay (RIA) using the Cobra Gamma Counter- (Packard, USA). The results indicates that there were significant difference for nutrition intakes including energy intakes (p<0.001), protein (p<0.05), fat (p<0.001), carbohydrate (p<0.001), Ca (p<0.05) and Fe (p<0.01) among three groups. Middle school gymnasts has significant higher value for energy intake and Ca than elementary and high school gymnasts. For elementary male gymnasts (3027.7 mg, 12.8 mg) significant higher values (p<0.001) were obtained for Na (3027.7 mg vs 2099.3 mg) and niacin (12.8 mg vs 8.6 mg) compared to female gymnasts. Also significant difference could be obtained for nutrition intakes between middle school male and female gymnasts except for fat, Fe and cholesterol intakes. Male gymnasts has significant higher values for energy intake, protein, carbohydrate, fiber, Ca, P, Na, K, vitaminA, vitamin B1, vitamin B2, niacin, and vitamin C. A similar trend was found for nutrition intakes between male and female high school gymnasts except for calcium. Male gymnasts had higher mean values for all nutrition intakes than female gymnasts. Significant difference were found for tranferrin (p<0.001), hematocrit (p<0.01), hemoglobin (p<0.05), MCV (p<0.001), MCH (p<0.001)and IGF-I (p<0.05) among groups. High school gymnasts had higher mean values for Hct. MCV, and MCH than elementary and middle school gymnasts. IGF-I is significantly related to body weight, BMI, and %fat. Further studies are required to examine the long-term effects of gymnastics training on circulating growth factors. |
Key Words:
dietary intake, growth hormone, Insulin-Like growth factor-1 |
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