The importance of iron for health and how to get enough

As a nutritionist I consider myself be fairly healthy and believe I can meet my nutritional requirements through my diet. However, things are never quite that straightforward when it comes to nutrition. When I was studying for my degree, after visiting my GP for an unrelated matter, I was surprised to learn that I had iron-deficient anaemia and that this is the most common nutritional deficiency in the world.

What is iron ?

Iron is a micronutrient that is needed to carry oxygen around our red blood cells for an

effective immune system and energy metabolism. This is why if you’re not getting enough;

you can feel tired or get out of breath easily.

Which foods contain iron ?

We can get it from animal sources which is known as ‘haem iron’ and plant sources which is ‘non-haem’ iron.

Examples include; red meat and poultry, particularly offal such as liver (however, liver is not

recommended in pregnancy due to its high vitamin A content) as well as eggs and to a lesser extent, fish.

Plant sources include cereal products (especially fortified breakfast cereals and flour). Vegetables; such as broccoli and dark green leafy veg. Pulses, beans and legumes, including chickpeas, lentils and peas. Nuts, seeds (especially sesame and sunflower) and dried fruits such as prunes, figs and apricots. Tofu is another good source.

How much should I be getting in my diet?

The UK Reference Nutrient Intake (RNI) for adult males (aged 19-50 years) is 8.7 mg per day and for females (aged 11-50 years) 14.8 mg per day (due to menstruation). Infants and children require less, with the recommended intakes increasing gradually. For post-menopausal women, requirements drop to 8.7 mg per day. There are no changes to recommendations during pregnancy as although there are greater requirements for iron, the body is able to adjust due to the cessation of periods and an increased absorption capacity. That being said, if your have low iron levels pre-pregnancy, seeking medical advice is recommended.

How do I know if I'm getting enough ?

Although we can examine our dietary intake amounts, it’s not quite that simple due to

differences in bioavailability. Whilst we get most of our dietary iron from plant sources, the

body isn’t able to absorb this as efficiently as haem iron. So, although it only contributes to

approximately 10-15% of total iron intake in meat-eating populations, it could contribute

around 40% of the total absorbed. For example; there is more iron in spinach than steak but our body will only absorb a small amount from the spinach.

Absorption also depends on factors such as our overall health or genetic diseases (e.g.

haemochromatosis) and dietary factors; where certain foods can be enhancers and

inhibitors as to how much non-haem iron is absorbed. These are important to consider,

especially if you are vegetarian or plant based.

Phytates which are found in grains, nuts, seeds and legumes bind to non-haem iron in the

intestine, which reduces absorption. Similarly, polyphenols, such as tannins in tea can

reduce absorption of non-haem iron by around 79-94%. Calcium, as found in milk and dairy products can also affect the absorption of haem as well as non-haem iron.

However, vitamin C, found in fruit and vegetables, overcomes these inhibitors and aids the absorption of non-haem iron. Furthermore, eating haem iron at the same time as non-haem also helps because muscle tissue is an enhancer.

What should I do ?

We eat foods, not ‘nutrients’, so consider your overall meal, aiming to include vitamin C or

animal iron with plant iron sources to improve absorption. Also, even though we are a

nation of tea drinkers, try not to have that cuppa with, or straight after your meal. You could

have a small glass of orange juice instead, making the most of the benefits of vitamin C. As

with many things in nutrition, the best overall advice is to have a varied diet, to ensure that

you are getting the all the nutrients you need.

Finally, if you think you may be iron deficient (do you have heavy periods for example ?), see

your GP who can do a simple blood test to check. It’s really common and you may need to

take supplements. Symptoms include; tiredness, shortness of breath, heart palpitations and pale skin. It’s important to do this as whilst the body does a great job of regulating iron

levels, if you have too much, such as through excessive supplementation, it can be toxic.

If you would like advice on your iron, or your overall nutrient intake, please do get in touch for a free discovery call.

Book here: https://calendly.com/rachelfletchernutrition/15min

References

British Dietetic Association. https://www.bda.uk.com/resource/iron-rich-foods-iron-

deficiency.html

British Nutrition Foundation. https://www.nutrition.org.uk/nutritionscience/nutrients-food-

and-ingredients/minerals-and-trace-elements.html?limit=1&start=8

Department of Health. (1991) Dietary reference values for food energy and nutrients for the

United Kingdom. HMSO

Gandy, J., Madden, A., & Holdsworth, M. (2012). Oxford handbook of nutrition and

dietetics (2nd ed.). Oxford: Oxford University Press.

Hurrell, R., & Egli, I. (2010). Iron bioavailability and dietary reference values. American

Journal Of Clinical Nutrition, 91(5), 1461S–1467S.

Hurrell, R., Reddy, M., & Cook, J. (1999). Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. British Journal of Nutrition, 81(4), 289–295.

Mann, J., & Truswell, A. (2017). Essentials of human nutrition (Fifth edition.). Oxford: Oxford University Press.

National Health Service https://www.nhs.uk/conditions/iron-deficiency-anaemia/

Whitney, E., & Rolfes, S. (2016). Understanding nutrition. (Fourteenth edition.). Australia: