Iron, despite being the most abundant element on the planet, is the most common micronutrient deficiency across nations.
Why do I need Iron?
Iron has important functions in the body including growth and development and the formation of haemoglobin, a protein that transports oxygen from the lungs to all the muscles in the body. And the more oxygen the muscles have, the more energised the person feels. The opposite is also true, that is why one of the main symptoms of iron deficiency is feeling tired. If left untreated, iron deficiency can become anaemia, which typically results in a lack of energy to carry out daily tasks and exercise, impaired focus and memory function, impaired immune system and difficulty in maintaining body temperature (feeling unusually cold). However, these symptoms can manifest in the absence of anaemia and in the presence of iron deficiency only.
How common is Iron deficiency anaemia?
Globally speaking, 29.9% of women of reproductive age, 36.5% of pregnant women and 39.8% of children aged under 5 suffer from iron deficiency anaemia (1). In the United Kingdom (UK), iron deficiency anaemia prevalence is 12% and 23% amongst women of reproductive age and pregnant women, respectively (2). Women of reproductive age are more susceptible to iron deficiency due to menstruation, and during adolescence, this is exacerbated due to rapid growth as well as menstruation. Pregnant women have more blood during pregnancy to supply the placenta and support the baby’s growth. However, there is no increase in the amount of iron requirements because the cessation of menstruation should make up for the higher demand. With that being said, many women are already suffering from iron deficiency at the start of pregnancy, hence the high rates of anaemia in this group. Small children are also a vulnerable group due to rapid growth and not eating enough iron-rich foods.
What are good nutritional sources of Iron?
There are two types of iron: haem and non-haem iron. Haem iron comes from animal sources and non-haem iron comes from plant sources. Good sources of haem iron are red meat, poultry, fish and eggs while good sources of non-haem iron are tofu, spinach, broccoli, lentils, beans, nuts and some dried fruits such as apricot and raisins. While both haem and non-haem iron are nutritionally similar, the absorption of non-haem iron is less efficient than that of haem iron, therefore a higher amount needs to be consumed. To improve iron absorption from plant sources it is recommended to add a source of vitamin C to the meal, for example, squeezing lemon over spinach or having an orange for dessert after an iron-rich meal. It is also worth mentioning that some compounds decrease the absorption of iron by the body such as polyphenols, found in tea and coffee, therefore it has been advised to avoid drinking tea and coffee for at least one hour after consuming an iron-containing meal as polyphenols in these drinks may decrease iron absorption by 60 to 80% (3). Phytic acids found in legumes, nuts and seeds also reduce the absorption of iron by the body and a good way to reduce phytic acids in these foods is to soak them for a few hours before consuming.
Studies also found that vitamin D deficiency decreases iron absorption in the body (4, 5), thus following the National Health Service (NHS) recommendations to take 10 micrograms of vitamin D per day during autumn and winter months, when typically in the UK, the population does not get enough sunshine, may help improve iron deficiency.
How much Iron do I need?
It is recommended that women of reproductive age consume 14.8 milligrams of iron per day, while post-menopausal women and men’s requirement is 8.7 milligrams per day (6). For example, 200 grams of beef steak has 5 milligrams of iron, while 100 grams of tofu contains 5.4 milligrams. Spinach is also high in iron, containing 2.7 mg per 100 grams. Bear in mind that 100 grams of spinach is a substantial portion when uncooked; hence, larger quantities need to be consumed if relying on plants to meet iron recommendations.
What about Iron supplements?
It is always preferred to obtain essential nutrients from a well-balanced diet. However, in some cases, individuals may need to take supplements to meet their daily requirements. In the case of iron supplements, it is essential to seek advice from a doctor first. They can provide referrals for a blood test to check for iron deficiency and prescribe the appropriate dosage, since excess iron in the body can lead to toxicity, a condition called iron overload. This occurs when the body stores too much iron, which can damage organs such as the liver, heart and pancreas. Individuals who have a genetic condition called hemochromatosis are particularly at risk of iron overload.
Important note: these recommendations are not substitutions for medical advice and if you feel unwell or think you may be suffering from iron deficiency, always consult a qualified medical doctor for advice.
References:
1-World Health Organisation (WHO) (2023). Anaemia in women and children. https://www.who.int/data/gho/data/themes/topics/anaemia_in_women_and_children
2-National Institute for Health and Care Excellence (2023, April). Anaemia: iron deficiency. How common is it? https://cks.nice.org.uk/topics/anaemia-iron-deficiency/background-information/prevalence/
3-Nelson, M., & Poulter, J. (2004). Impact of tea drinking on iron status in the UK: a review. Journal of human nutrition and dietetics : the official journal of the British Dietetic Association, 17(1), 43–54. https://doi.org/10.1046/j.1365-277x.2003.00497.x
4-Nur-Eke, R., & Özen, M. (2020). The Relationship between Vitamin D Levels and Iron Deficiency and Anemia in Adults Applied for Periodic Medical Examination. Clinical laboratory, 66(6), 10.7754/Clin.Lab.2019.190918. https://doi.org/10.7754/Clin.Lab.2019.190918
5-Smith, E. M., & Tangpricha, V. (2015). Vitamin D and anemia: insights into an emerging association. Current opinion in endocrinology, diabetes, and obesity, 22(6), 432–438. https://doi.org/10.1097/MED.0000000000000199
6-Wiseman, M. (1992). The COMA report: dietary reference values for food energy and nutrients for the United Kingdom. British Food Journal, 94(3), 7-9. https://doi.org/10.1108/00070709210010472
