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Does Iron Supplementation Improve Performance in Iron-Deficient Nonanemic Athletes?

ABSTRACT: CONTEXT:Supplementing iron-deficient nonanemic (IDNA) athletes with iron to improve performance is a trend in endurance sports. OBJECTIVES:To investigate the benefits of iron on performance, identify a ferritin level cutoff in IDNA athletes, and determine which iron supplementation regimens are most effective. DATA SOURCES:A search of the PubMed, CINAHL, Embase, ERIC, and Cochrane databases was performed in 2014 including all articles. Citations of pertinent review articles were also searched. In 2017, the search was repeated. STUDY SELECTION:Inclusion criteria comprised studies of level 1 to 3 evidence, written in the English language, that researched iron supplementation in nonanemic athletes and reported performance outcomes. STUDY DESIGN:Systematic review. LEVEL OF EVIDENCE:Level 3. DATA EXTRACTION:The search terms used included athletic performance, resistance training, athletes, physical endurance, iron, iron deficiency, supplement, non-anemic, low ferritin, ferritin, ferritin blood level, athletes, and sports. RESULTS:A total of 1884 studies were identified through the initial database search, and 13 were identified through searching references of relevant review articles. A subsequent database search identified 46 studies. Following exclusions, 12 studies with a total of 283 participants were included. Supplementing IDNA athletes with iron improved performance in 6 studies (146 participants) and did not improve performance in the other 6 studies (137 participants). In the 6 studies that showed improved performance with iron supplementation, all used a ferritin level cutoff of ?20 ?g/L for treatment. Additionally, all studies that showed improved performance used oral iron as a supplement. CONCLUSION:The evidence is equivocal as to whether iron supplementation in IDNA athletes improves athletic performance. Supplementing athletes with ferritin levels <20 ?g/L may be more beneficial than supplementing athletes with higher baseline ferritin levels.

SUBMITTER: Rubeor A

PROVIDER: S-EPMC6116100 | biostudies-literature | 2018 Sep/Oct

REPOSITORIES: biostudies-literature

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Does Iron Supplementation Improve Performance in Iron-Deficient Nonanemic Athletes?

Rubeor Amity A Goojha Carmen C Manning Jeffrey J White Jordan J

Sports health 20180524 5

<h4>Context</h4>Supplementing iron-deficient nonanemic (IDNA) athletes with iron to improve performance is a trend in endurance sports.<h4>Objectives</h4>To investigate the benefits of iron on performance, identify a ferritin level cutoff in IDNA athletes, and determine which iron supplementation regimens are most effective.<h4>Data sources</h4>A search of the PubMed, CINAHL, Embase, ERIC, and Cochrane databases was performed in 2014 including all articles. Citations of pertinent review articles ...[more]

PMID: 29792778

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Project description:Anemia is common in pregnancy and increases the risk of adverse outcomes. Iron deficiency is a leading cause of anemia in sub-Saharan Africa, and iron supplementation is the standard of care during pregnancy; however, recent trials among children have raised concerns regarding the safety of iron supplementation in malaria-endemic regions. There is limited evidence on the safety of iron supplementation during pregnancy in these areas.To evaluate the safety and efficacy of iron supplementation during pregnancy in a malaria-endemic region.We conducted a randomized, double-blind, placebo-controlled clinical trial among pregnant women presenting for antenatal care in Dar es Salaam, Tanzania, from September 28, 2010, through October 4, 2012. Iron-replete, nonanemic women were eligible if they were uninfected with human immunodeficiency virus, primigravidae or secundigravidae, and at or before 27 weeks of gestation. Screening of 21,316 women continued until the target enrollment of 1500 was reached. Analyses followed the intent-to-treat principle and included all randomized participants.Participants were randomized to receive 60 mg of iron or placebo, returning every 4 weeks for standard prenatal care, including malaria screening, prophylaxis with the combination of sulfadoxine and pyrimethamine, and treatment, as needed.The primary outcomes were placental malaria, maternal hemoglobin level at delivery, and birth weight.Among 1500 study participants (750 randomized for each group), 731 in iron group and 738 in placebo group had known birth outcomes and 493 in iron group and 510 in placebo group had placental samples included in the analysis. Maternal characteristics were similar at baseline in the iron and placebo groups, and 1354 (91.7%) used malaria control measures. The risk of placental malaria was not increased by maternal iron supplementation (relative risk [RR], 1.03; 95% CI, 0.65-1.65), and iron supplementation did not significantly affect birth weight (3155 vs 3137 g, P =?.89). Compared with placebo, iron supplementation significantly improved the mean increase from baseline to delivery for hemoglobin (0.1 vs -0.7 g/dL, P <?.001) and serum ferritin (41.3 vs 11.3 µg/L, P <?.001). Iron supplementation significantly decreased the risk of anemia at delivery by 40% (RR, 0.60; 95% CI, 0.51-0.71) but not severe anemia (RR, 0.68; 95% CI, 0.41-1.14). Iron supplementation significantly reduced the risk of maternal iron deficiency at delivery by 52% (RR, 0.48; 95% CI, 0.32-0.70) and the risk of iron deficiency anemia by 66% (RR, 0.34; 95% CI, 0.19-0.62).Prenatal iron supplementation among iron-replete, nonanemic women was not associated with an increased risk of placental malaria or other adverse events in the context of good malaria control. Participants receiving supplementation had improved hematologic and iron status at delivery compared with the placebo group. These findings provide support for continued administration of iron during pregnancy in malaria-endemic regions.clinicaltrials.gov Identifier: NCT01119612.

Project description:BACKGROUND:A limited amount of research has demonstrated beneficial effects of caffeine and theanine supplementation for enhancement of mental performance. The purpose of this investigation was to determine whether the acute ingestion of a supplement containing caffeine, theanine and tyrosine improves mental and physical performance in athletes. METHODS:Twenty current or former male collegiate athletes (age: 20.5?±?1.4 y; height: 1.82?±?0.08?m; weight: 83.9?±?12.6?kg; body fat: 13.8?±?5.6%) completed this randomized, double-blind, placebo-controlled crossover trial. After familiarization, each participant completed two identical testing sessions with provision of a proprietary dietary supplement (SUP) containing caffeine theanine and tyrosine or a placebo (PL). Within each testing session, participants completed assessments of mental and physical performance before and after provision of SUP or PL, as well as after two rounds of exercise. Assessments were performed using a performance testing device (Makoto Arena) that evaluated multiple aspects of mental and physical performance in response to auditory and visual stimuli. Testing was performed both with the body in a static position and during dynamic movement. General linear models were used to evaluate the effects of SUP and PL on performance. RESULTS:Changes in movement accuracy during performance assessment were greater following SUP ingestion as compared to PL for both static and dynamic testing (SUP: +?0.4 to 7.5%; PL: -?1.4 to 1.4% on average; p?<?0.05). For dynamic testing, the change in number of targets hit was higher and the change in average hit time was lower with SUP as compared to PL (p?<?0.05). However, there were no differences between conditions for the changes in number of targets hit or average hit time during static testing. There were no differences in changes of subjective variables during either condition, and performance measures during the two rounds of exercise did not differ between conditions (p?>?0.05). DISCUSSION:The present results indicate that a combination of a low-dose of caffeine with theanine and tyrosine may improve athletes' movement accuracy surrounding bouts of exhaustive exercise without altering subjective variables. Based on this finding, supplementation with caffeine, theanine and tyrosine could potentially hold ergogenic value for athletes in sports requiring rapid and accurate movements. TRIAL REGISTRATION:NCT03019523. Registered 24 January 2017.

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Does Iron Supplementation Improve Performance in Iron-Deficient Nonanemic Athletes?

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Does Iron Supplementation Improve Performance in Iron-Deficient Nonanemic Athletes?

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