Marathon Runner with Iron Deficiency Without Anemia
A 28-year-old female marathon runner presents with fatigue and decreased performance over 3 months. She runs 60 miles per week and follows a vegetarian diet. She denies heavy menstrual bleeding but reports irregular periods. Labs: hemoglobin 13.2 g/dL, hematocrit 39%, ferritin 18 ng/mL, TIBC 450 µg/dL, transferrin saturation 15%. She asks about iron supplementation and whether she should take an iron pill daily. She also wants to know if she can improve her performance with beetroot juice or caffeine.
1. What is the diagnosis and what is the appropriate management of her iron status?
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The diagnosis is iron deficiency without anemia (ferritin <30 ng/mL, low transferrin saturation). Her hemoglobin is normal, but iron stores are depleted, which can impair performance. Management: oral iron supplementation. The optimal regimen is alternate-day dosing (e.g., 60-120 mg elemental iron every other day) because daily dosing increases hepcidin and reduces absorption. Take with vitamin C and on an empty stomach if tolerated. Avoid taking with calcium, tea, or coffee. Recheck ferritin in 8-12 weeks. If no improvement, consider IV iron. Dietary counseling to increase iron-rich foods (legumes, spinach, fortified cereals) and pair with vitamin C. She should also be screened for causes of iron loss (e.g., GI bleeding, though unlikely in a young athlete).
2. What is the evidence for beetroot juice and caffeine as ergogenic aids in this athlete?
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Beetroot juice is a source of dietary nitrate, which increases nitric oxide and may improve exercise efficiency and endurance performance, especially in recreational athletes. Evidence is moderate; effects are small and more pronounced in less-trained individuals. Typical dose: 300-600 mg nitrate (about 500 mL beetroot juice) 2-3 hours before exercise. Caffeine is a well-established ergogenic aid: 3-6 mg/kg taken 30-60 minutes before exercise improves endurance performance. It is not banned by WADA. However, individual responses vary, and side effects include insomnia, anxiety, and GI upset. She should trial these in training, not on race day. Both are permitted, but she should be aware of potential interactions and ensure hydration.