Endurance athletes may be at risk of iron depletion from increased losses.Other GI losses - eg, recurrent bleeding from haemorrhoids, dental bleeding or epistaxis.Non-steroidal anti-inflammatory drugs (NSAIDs). GI malignancy (although this tends to cause iron deficiency with anaemia).Helicobacter pylori colonisation reduces iron uptake.Achlorhydria (gastric acid maintains ferric iron in solution, so aids absorption) - eg, from proton pump inhibitors or post-gastrectomy.Excessive consumption of foods which reduce absorption - eg, cow's milk, tea.Low calorie intake in relation to iron requirement - eg, growing children, pregnant women and the elderly.Inadequate intake (nutritional iron deficiency): Iron is present in many foods, so iron intake per se is partly related to overall calorie intake, although subsequent absorption and metabolism are affected by many variables.Ĭauses of non-anaemic iron deficiency (aetiology).Iron requirements increase at times of growth (early childhood and adolescence), during pregnancy and with menstruation.A mature fetus has iron stores, which are required because breastfeeding does not meet the infant's iron requirements.Iron is lost from the body through sloughed skin cells and sloughed enterocytes from the gut, and through any form of blood loss.Hepcidin has an effect on the transfer of iron into plasma from enterocytes, hepatocytes and macrophages. The regulation of iron absorption and transport is complex there seems to be an important role for hepcidin, a hormone secreted by the liver.If needed it is converted to ferrous iron and transported in the circulation bound to transferrin. If iron is not required by the body it is stored by the iron storage protein ferritin. Absorption is inhibited by calcium, phytates (in some plant foods) and polyphenols (in tea and coffee). Non-haem iron absorption can be improved by the ingestion of meat and ascorbic acid (vitamin C). Ferrous iron can be absorbed directly by the intestinal cells ferric iron has to be converted before it can be absorbed. Non-haem iron may be in ferrous or ferric form.
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