Document Type

Thesis - University Access Only

Award Date

2011

Degree Name

Master of Science (MS)

Department / School

Health and Nutritional Sciences

Abstract

Purpose: The purpose of this study was to determine if weekly supplementation with 9 ounces of prepackaged lean beef sticks would maintain the iron status of collegiate endurance athletes. Methods: Thirty-four (20 female, 14 male) collegiate endurance athletes were stratified by gender, baseline serum ferritin concentration, and use of iron supplements and randomized into an intervention (n=18) or control (n=l6) group. The intervention group supplemented their usual diet with 9 ounces of prepackaged lean beef sticks per week and a daily multivitamin supplement containing 18 mg iron. The control group consumed their normal diet and the daily multivitamin supplement only. Body composition, dietary intake, and blood markers of iron status (hemoglobin, hematocrit, serum iron, serum ferritin, and total iron binding capacity) were measured at baseline and post-intervention. C-reactive protein was also measured at baseline and post-intervention to test for the presence of inflammation. Participants were categorized as iron deficient if serum ferritin was < 15 μg/L. Statistical analysis was performed using JMP®7. A two-way analysis of variance with group (Intervention vs. Control) and time as treatment factors was used to determine the main effect of beef supplementation on variables measured. Statistical significance was reached at p< 0.05. Results: None of the participants in this study were categorized as iron deficient at baseline or post- intervention. Heme-iron intake was significantly greater (p< 0.003) in the intervention group (3.1 ± 0.3 mg per day) compared to the control group (1.5 ± 0.3 mg per day) post- intervention. There were no group differences in hemoglobin, hematocrit, serum iron, or serum ferritin due to the intervention. Total iron binding capacity was improved in the intervention group versus the control (p=0.027). There was an effect of time on serum iron (p=0.002, intervention 117. 7 ± 9.9 to 78. 7 ± 9.9 μg/dL; control 131. 7 ± 11.7 to 98.2 ± 11. 7 μg/dL), hemoglobin (p=0.009, intervention 12.8 ± 0.5 to 11.4 ± 0.6 g/dL; control 13.5 ± 0.6 to 11.6 ± 0.7 g/dL) and serum ferritin (p=0.015, intervention 56.7 ± 4.6 to 72.7 ± 4.9 μg/L; control 56.1 ± 5.3 to 68.0 ± 6.5 μg/L). C-reactive protein concentration was not significant in either group at any time throughout the study. Conclusion: The results of this study suggest that daily intake of bioavailable iron may attenuate the effects of exercise on the iron status of endurance athletes.

Key Words: bioavailable, iron status, iron deficiency, heme iron, non-heme iron, hemoglobin, hematocrit, serum ferritin, total iron binding capacity, C-reactive protein, athletes, lean beef

Library of Congress Subject Headings

College athletes -- Nutrition

Iron in the body

Beef

Format

application/pdf

Number of Pages

49

Publisher

South Dakota State University

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