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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Iron Deficiency and Reduced Work Capacity: A Critical Review of the Research to Determine a Causal Relationship

Despite current recommendations on the management of pre-operative anaemia, there is no pragmatic guidance for the diagnosis and management of anaemia and iron deficiency in surgical patients. A number of experienced researchers and clinicians took part in an expert workshop and developed the following consensus statement. After presentation of our own research data and local policies and procedures, appropriate relevant literature was reviewed and discussed. We developed a series of best-practice and evidence-based statements to advise on patient care with respect to anaemia and iron deficiency in the peri-operative period. These statements include: a diagnostic approach for anaemia and iron deficiency in surgical patients; identification of patients appropriate for treatment; and advice on practical management and follow-up. We urge anaesthetists and peri-operative physicians to embrace these recommendations, and hospital administrators to enable implementation of these concepts by allocating adequate resources.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/anae.13773

International consensus statement on the peri-operative management of anaemia and iron deficiency.

IN early times the earth had a reducing atmosphere, and an abundance of ferrous iron was present for incorporation into biologic molecules.1 Later, with an increase in atmospheric oxygen, iron existed largely in its less available ferric form,2 and special devices had to be developed by life forms for the acquisition of iron. Bacteria, for example, synthesize and excrete high-affinity chelating agents that extract otherwise unavailable iron from the surrounding environment.3 The roots of plants also secrete substances that augment iron absorption.4 In mammalian species a "shuttle" protein in the upper intestine — mucosal transferrin — appears to perform this . . .

Perspectives in Iron Metabolism

Low molecular weight intracellular iron transport compounds.

The location and function of iron in the central nervous system are reviewed with particular emphasis on human biology Iron is distributed to different cell types in the brain in a heterogeneous fashion through the action of transferrin, transferrin receptors, and the metabolic needs of those cells The function of this iron and its storage is documented in states of growth and development as well as during pathological states associated with aging The information relating this biology to current observations of attention deficits in iron-deficient humans is also reviewed

Iron in the Brain

Work performance on a treadmill has been evaluated in normal and iron-deficient rats. Anemia was removed as a variable by adjusting the hemoglobin of all animals to the same concentration. At a hemoglobin compatible with normal work performance, iron-deficient animals showed a marked impairment of running ability as compared to control animals. Iron therapy corrected the disability within 4 days. Concentrations of the cytochrome pigments and myoglobin, and rates of oxidative phosphorylation with pyruvate-malate, succinate, and alpha-glycerophosphate as substrates were all reduced in mitochondrial preparations from skeletal muscle of iron-deficient rats, but only the rate of phosphorylation with alpha-glycerophosphate as substrate increased significantly and in parallel with the recovery in work performance of the iron-deficient rats treated with iron dextran.

/pdf/iron-deficiency-in-the-rat-physiological-and-biochemical-2mfz9uz2iw.pdf

A R Inamdar

Papers

Iron deficiency in the rat. Physiological and biochemical studies of muscle dysfunction.