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Cited by 1,186Iron Metabolism and DisordersCardiovascular and exercise physiologyErythropoietin and Anemia Treatment

Iron deficiency and reduced work capacity: A critical review of the research to determine a causal relationship

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Haas, Jere D., Brownlie, Thomas·2001·The Journal of Nutrition
DOI 10.1093/jn/131.2.676s
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Abstract

The causal relationship between iron deficiency and physical work capacity is evaluated through a systematic review of the research literature, including animal and human studies. Iron deficiency was examined along a continuum from severe iron-deficiency anemia (SIDA) to moderate iron-deficiency anemia (MIDA) to iron deficiency without anemia (IDNA). Work capacity was assessed by aerobic capacity, endurance, energetic efficiency, voluntary activity and work productivity. The 29 research reports examined demonstrated a strong causal effect of SIDA and MIDA on aerobic capacity in animals and humans. The presumed mechanism for this effect is the reduced oxygen transport associated with anemia; tissue iron deficiency may also play a role through reduced cellular oxidative capacity. Endurance capacity was also compromised in SIDA and MIDA, but the strong mediating effects of poor cellular oxidative capacity observed in animals have not been demonstrated in humans. Energetic efficiency was affected at all levels of iron deficiency in humans, in the laboratory and the field. The reduced work productivity observed in field studies is likely due to anemia and reduced oxygen transport. The social and economic consequences of iron-deficiency anemia (IDA) and IDNA have yet to be elucidated. The biological mechanisms for the effect of IDA on work capacity are sufficiently strong to justify interventions to improve iron status as a means of enhancing human capital. This may also extend to the segment of the population experiencing IDNA in whom the effects on work capacity may be more subtle, but the number of individuals thus affected may be considerably more than those experiencing IDA.

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  • Even mild iron deficiency can adversely affect cognitive performance, behavior, physical growth of infants, preschool and school age children and physical work capacity and work performance of adults.

    “Even mild iron deficiency can adversely affect cognitive performance, behavior, physical growth of infants, preschool and school age children and physical work capacity and work performance of adults (Brabin et al, 2001;Haas and Brownlie, 2001).”

    From Iron, Oxidative Stress and Health (2012) · cites this paper as Haas and Brownlie, 2001

    The Discussion and Energetic efficiency sections report adverse effects of iron deficiency on adults’ physical work capacity and the energy cost of work, including effects in nonanemic women. The paper does not establish the claimed effects of mild deficiency on cognitive performance, behavior, or physical growth across infants, preschoolers, and school-age children; in the discussion on p. 688S, Haas says there is virtually no work on young children in the work-capacity research he reviews. (LLM, conf=0.86)

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  • In trials where a proportion of participants were anaemic at enrolment, iron supplementation has previously been associated with improved maximal and submaximal exercise performance.

    “In trials where a proportion of participants were anaemic at enrolment and with the knowledge that anaemia results in decreased physical capacity, iron supplementation has previously been associated with improved maximal and submaximal exercise performance.5–8”

    From Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials (2018) · cites this paper as [8]

  • Iron deficiency decreases physical performance, work efficiency and working capacity.

    “Besides increasing perceived fatigue, iron deficiency is also known to decrease physical performance, work efficiency and working capacity [113].”

    From Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence (2020) · cites this paper as [113]

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Research works printed but not linked: 1

  1. Li, R. (1993) Functional Consequences of Iron Deficiency in Chinese Female Workers. Doctoral thesis, Wageningen Agricultural University, Wageningen, The Netherlands.

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Authors
Haas, J. D., & Brownlie, T.
Affiliations
Cornell University (US)
Corresponding author
Haas, Jere D.
ORCID
Haas, Jere D.
Venue
The Journal of Nutrition
Publisher
Elsevier BV
Published
2001-02
Volume
131
Issue
2
Pages
676S-690S
ISSN
0022-3166 (ISSN-L)
DOI
10.1093/jn/131.2.676s
OpenAlex
W1914307777
Cited by
1,186
References
40
Citations by year
2026: 36 · 2025: 42 · 2024: 53 · 2023: 87 · 2022: 62 · 2021: 92 · 2020: 74 · 2019: 64 · 2018: 66 · 2017: 64 · 2016: 62 · 2015: 60 · 2014: 50 · 2013: 63 · 2012: 45
FWCI
8.42
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Nutrition (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • World Health Organization
  • National Institutes of Health
  • National Institute of Diabetes and Digestive and Kidney Diseases (T32-DK 07158, T32DK007158)
Topics
  • Health Sciences › Medicine › Hematology › Iron Metabolism and Disorders
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
  • Health Sciences › Medicine › Hematology › Erythropoietin and Anemia Treatment
Keywords
iron deficiency, iron deficiency anemia, work capacity, cardiorespiratory fitness, endurance, energy efficiency, oxygen transport, labor productivity, human capital
MeSH terms
Iron Deficiencies, Algorithms, Anemia, Animals, Efficiency, Energy Metabolism, Hemoglobin A, Humans, Iron, Oxygen Consumption, Physical Endurance, Physical Fitness, Work, Reproducibility of Results, Causality, Confounding Factors, Epidemiologic, Anemia, Iron-Deficiency

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