The Importance of Iron Supplementation for Female Athletes Marissa Uhlhorn Aramark Dietetic intern 4/20/17

Iron’s Role in the Body Essential micronutrient involved in blood production 70% of the body’s iron is found in red blood cells (hemoglobin) and muscle cells (myoglobin)  Hemoglobin: Transfers oxygen in blood from the lungs to the tissues Myoglobin: Accepts, stores, transports, and releases oxygen in muscle 6% of body’s iron is a component of proteins essential for respiration and energy metabolism 25% is stored as ferritin (protein that binds to iron)- found in liver, spleen, muscle, bone marrow

Dietary Sources of Iron To maintain sufficient iron levels, recommended daily allowance (RDA) for healthy premenopausal women is 18 mg/ day LENTILS 1 cup = 6.59 mg of iron SPINACH 1 cup = 6.43 mg of iron BEEF 3 ounces = 5.24 mg of iron Dark chocolate 1 square = 5 mg of iron cashews 1 ounce= 1.7 mg of iron Kidney beans 1 cup = 5.2 mg of iron OYSTERS 3 ounces= 5.91 mg of iron TOMATOES 1 cup = 3.39 mg of iron CHICKPEAS 1 cup = 4.74 mg of iron Pumpkin seeds 1 ounce = 4 mg of iron Vitamin C enhances the bioavailability of nonheme iron Nonheme- Non meat sources Meat sources- heme + nonheme

Iron and Hemoglobin Levels Normal Hemoglobin Levels: Men: 13.5-17.5 g/dL Women: 12.0-15.5 g/dL (ND uses 11.4-15.4 g/dL) Normal Ferritin Levels (sFer): Men: 24-336 ng/mL Women: 11-307 ng/mL ND uses 14-150 ng/mL Hepcidin: Circulating Hormone-negative regulator of iron status Upregulated by inflammation Increased levels linked to decreased iron levels and prevention of iron absorption Decreased levels linked to increased iron levels and facilitation of iron absorption

Causes of Iron deficiency in Athletes Hemolysis (physical sheering of red blood cells –foot strike & impact) Poor dietary intake Increased iron losses: Intestinal bleeding, hematuria (blood lost in urine), sweat Altered intestinal iron absorption caused by effects of inflammation due to training. Menstrual losses (in females)

iron deficiency and Anemia Functional or Subclinical Iron Deficiency (ID) When iron stores have become depleted but Hgb has not yet declined to an anemic level: Tissue oxidative capacity is affected , endurance performance is impaired Hgb synthesis and O2 transport are not affected Severe Iron Deficiency (ID) Hgb synthesis compromised- depleted iron stores – Iron Deficiency Anemia (IDA) Reduced O2 transports (V02 Max), Reduced tissue oxidative capacity (endurance capacity, energetic efficiency) SUMMARY:  Limits the body’s capacity to carry and deliver oxygen Decreasing maximal oxygen uptake (VO2max) Decreased performance levels Associated with higher blood lactate concentrations during exercise Increased fatigue Immune abnormalities

Iron Overload Definition: Increased total body Fe stores with or without organ dysfunction Primary iron overload: defect in regulation of iron balance Secondary iron overload: Excess iron intake (dietary or supplementation) Long term effects: organ and cellular damage due to oxidative stress & formation of free radicals Tolerable Upper Level: 45 mg/day elemental Iron with already normal levels

Current Practices at Notre Dame Female athletes are screened 2x/year for iron deficiency Serum Ferritin levels checked- most common index of body Fe stores ND’s Normal Ferritin Range: 13-150 ng/mL ND’s Normal Hemoglobin Range: 11.4-15.4 g/dL If Ferritin levels are below 40 ng/mL: One 65 mg supplement of Nature Made Iron Tablet given daily Mon-Sun (equivalent to 325 mg Ferrous Sulfate/day) If Ferritin levels below 20 ng/mL: Two 65 mg supplements of Nature Made Iron Tablets given daily Mon-Fri (equivalent to 740 mg Ferrous Sulfate/day) OR 1-2 Vitron C (elemental iron + Vitamin C) given daily Mon-Sun (1 tablet contains 65 mg elemental Fe) If stomach issues- slow releasing iron supplement can be given (50mg) OR Easy Iron Chewables (20 mg)

Current Evidence-Based Recommendations Iron Supplementation for: Those with IDA (Hgb <12 g/dL, sFer <12 ng/L) Athletes with consistent suboptimal dietary intake (e.g., vegetarians/vegans, weight-control sports, endurance runners, etc.). Individuals with normal Fe status (Hgb >12 to 13 g/dL, sFer >30 ng/L) likely will not benefit from supplementation If Iron deficient (decreased Ferritin levels): Supplement with 100 mg Ferrous Sulfate daily (20 mg elemental iron) Monitor iron status throughout training season Monitor compliance to supplementation and encourage dietary intake Absorption: Most efficient/absorbable when consumed daily with source of Vitamin C (citrus juice) Less absorbable when consumed with polyphenolic compounds such as coffee or tea Less absorbable when consumed with calcium rich foods or calcium supplements (including Tums)

Current Evidence-Based Recommendations Summary Low to moderate iron supplementation (100mg/d) among female athletes has been shown to: Improve endurance times( longer time to exhaustion) Improve time-trial times (completed same amount of work using less energy) Increase maximal oxygen uptake (VO2max) therefore improving overall performance Female athletes most at risk of ID should be screened using Hgb and sFer. Monitor Fe status, treatment, and counseling to ensure sufficient dietary intakes and prevent further decrements in Fe status with training.

References Journal Articles: http://journals.lww.com/acsm-csmr/Abstract/2013/07000/Iron_Supplementation_for_Female_Athletes__Effects.9.aspx http://jn.nutrition.org/content/early/2014/04/09/jn.113.189589.full.pdf+html http://www.nature.com/ejcn/journal/v61/n1/full/1602479a.html https://www.ucsfhealth.org/education/hemoglobin_and_functions_of_iron/ http://www.eatright.org/resource/health/wellness/preventing-illness/iron-deficiency https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

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