Why do people become iron deficient?
Do you have low iron?
Sub-optimal levels of iron are common in Australia - in both adults and children.
When it comes to iron levels, serum ferritin is the most accurate test to determine total body iron stores. The reference range for ferritin is 30 - 300 micrograms per litre, however some health practitioners prefer to use the “optimal” range, 50 - 150 micrograms per litre.
Iron deficiency anaemia affects women more than men. It is estimated that 12% of women in Australia have anaemia and 20% of people aged over 85 years. Young children are commonly iron deficient too, with the condition affecting 8% of Australian preschool-aged children.
Factors contributing to iron deficiency include:
Lack of iron-rich foods in the diet
A lack of dietary iron is particularly common in people eating a vegan or vegetarian diet as the iron obtained from plant sources (non-haem iron) is not as well absorbed as the iron from animal products (haem iron)
Drinking a lot of cow’s milk
Calcium competes for the same absorption pathway as iron in the body so drinking a lot of cow’s milk, particularly with meals, can reduce the amount of iron absorbed from food.
Age and stage of life
Growth spurts burn through the body’s iron reserves so low iron is common in periods of rapid growth, e.g. early childhood and adolescence. Older adults also often have low iron due to eating less food.
Pregnancy
During pregnancy the body needs more iron to make blood cells for the growing baby.
Digestive disorders
Conditions such as coeliac disease, Crohn’s disease, leaky gut, helicobacter pylori and bowel cancer all impair absorption of iron in the digestive tract.
Excessive menstrual bleeding
Heavy bleeding reduces the number of circulating red blood cells and depletes the body’s iron stores.
Long-term use of proton pump inhibitors (PPIs)
PPIs (e.g. Nexium, Losec and Somac), when taken for long periods of time, are believed to affect iron metabolism by suppressing its absorption.
Vitamin D deficiency
Vitamin D influences iron absorption and production of red blood cells and studies have shown an association between low vitamin D levels and reduced serum ferritin.
Vigorous exercise
Intense or endurance exercise creates greater iron demands due to iron being lost through heavy sweating and the need for iron to transport oxygen through the body.
Intestinal parasites
Low iron levels are common in people infected with parasites - particularly helminths (e.g. pinworms, roundworms and tapeworms) and protozoa (e.g. dientamoeba fragilis and giardia) - as these parasites feed on the blood of the host, leading to loss of iron.
Stay tuned as my next post will be sharing the signs and symptoms to look out for if you think you may be low in iron.
References
Gopalakrishnan S et al, 2018, ‘Intestinal parasitic infestations and anemia among urban female school children in Kancheepuram district, Tamil Nadu’, Journal of Family Medicine and Primary Care, vol 7, no.6, pp. 1395-1400.
Graczykowska K et al, 2021, ‘The consequence of excessive consumption of cow’s milk: protein-losing enteropathy with Anasarca in the course of iron deficiency anemia - case reports and a literature review, Nutrients, vol 13 no. 3 p. 828.
Hamano H et al, 2019, ‘Proton pump inhibitors block iron absorption through direct regulation of hepcidin via the aryl hydrocarbon receptor-mediated pathway’, Toxicology Letters, vol 318, p.86-91.
Malczewska-Lenczowska J et al, 2018, ‘The Association between Iron and Vitamin D Status in Female Elite Athletes’, Nutrients, vol 10, no 2, p.167.
Walter and Eliza Hall Institute of Medical Research, 2022, ‘Anaemia’, WEHI, Victoria, viewed 13 March 2023, https://www.wehi.edu.au/research-diseases/development-and-ageing/anaemia#:~:text=Anaemia%20is%20a%20common%20condition,over%2085%20years%20are%20anaemic.