how much iron?

Common things I get asked are "should I supplement iron?" or "can I get enough iron on a plant-based diet", and I often hear comments such as "I feel anaemic." In this recent blog I wrote for Rhitrition, I look into all of these questions!


What is iron?

Iron is an important mineral in human biology, playing a vital role in oxygen utilisation this includes helping ATP (the primary energy molecule in our bodies), carrying oxygen in our blood, muscle movemement and development, and to support our immune system (1-7).


Iron comes in two forms (2, 8, 9):

  1. Haem iron (Fe2+) from animal and animal-based products such as red meat and seafood.

  2. Non-haem iron (Fe3+) from plant-based products such as dark leafy green vegetables beans, grains, nuts, and seeds.

Iron recommendations are related to its uses, and losses for example requirments are increased during periods of growth, and in people who menustrate:

  • Adolescent males (11-18) - 11.3mg/ day

  • Adult males (19+) - 8.7mg/ day

  • Females 11-50 years (pre-menopause) - 14.8mg/ day

  • Adult females (post-menopause) - 8.7mg/ day

Plant-based diets

Iron is absorbed in our bodies in the Fe2+ form, this is why it is more avaliable to us from animal products. However, a well-planned plant based diet can provide us with our iron recommendations. Here are some tips to ensure we get enough iron when following a plant-based dietary pattern (2, 10-13):

  • Include a diverse range of plant-based sources of iron.

  • Choose foods fortified with iron, such as some breakfast cereals. A food declaring iron in the nutrition label, needs to contain at least 15% per 100g = 2.1mg. Many fortified foods will contain higher amounts.

  • Eat vitamin C rich foods or drinks with sources of plant-based iron.

  • Avoid drinking tea and coffee during, just before and after our main meals.

Iron overload and supplementation

Unlike most other nutrients, we do not actually have an excretory pathway for iron, instead, our body controls how much it absorbs. This was an evolutionary advantage because iron sources were so scare, we needed to hang on to it. While a large proportion of individuals globally remain iron deficient, our bodies are smart, and during times where we require more iron, they bodies can absorb more from our food for example, people who menstruate or are pregnant (14-19)!


It must be noted that iron is a heavy metal, and can be potentially toxic to humans in excess amounts - called iron overload. Therefore, it is important to adhere to the recommendations, especially as we cannot actively excrete it once absorbed. Most people can get enough iron through their diet. If you are concerned about iron deficiency anaemia, it is important to speak with your GP or other registered healthcare professional who will be able to assess wheather you need a blood test to check for iron defiency and consider supplements as appropriate (14-19).


Resources

British Dietetic Association. Iron: Food Fact Sheet (2).

National Health Service. Iron. Vitamins and Minerals (9).

National Health Service. Start 4 Life (20).


References

(1)https://d1wqtxts1xzle7.cloudfront.net/36524777/G071123846-with-cover-page-v2.pdf?Expires=1636830726&Signature=NPNQ2KpEj49WFgf4MvUApwYIlfjsZduv3fZOhFK2lf8QBgByAh-~QjmXC9MITfJdvMY3RfVCtwyuAlSzIpYaeIdzq80l8se0L0VWTdBcMr20oClFN1SRhMRqDoPZLOkeIapfyKwP50HZySqUTABrD2NxKE~e~pqdDVhKUyjaRyV1nKdBmoUheRh5TaMowoaf7jVHbJTCzZqcYu9HOeUAi4R4K6qFVjJu-Zuj6STvA50KnPZO0yKuCn55JXiI9iCqiy5b6O0ceeBqcjpYY~CYgcgD-O1Icn2OmjU8X1JkjgkYUUoWz5MEcmqC9MQgM810SIYDyUIwsxS1GRkNbzwaMw__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA

(2) https://www.bda.uk.com/resource/iron-rich-foods-iron-deficiency.html

(3) https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119951438.eibc0098

(4) https://www.ncbi.nlm.nih.gov/books/NBK526105/

(5) https://www.frontiersin.org/articles/10.3389/fnins.2019.00165/full#:~:text=Excess%20iron%20accumulation%20in%20tissue,of%20diseases%2C%20including%20neurodegenerative%20diseases.

(6) https://academic.oup.com/jn/article/131/2/568S/4686826

(7)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3173740/

(8)https://www.nature.com/articles/ejcn2013100

(9)https://www.nhs.uk/conditions/vitamins-and-minerals/iron/

(10)https://www.ncbi.nlm.nih.gov/books/NBK448204/

(11)https://pubmed.ncbi.nlm.nih.gov/20200263/

(12)https://academic.oup.com/ajcn/article/71/5/1147/4729231

(13)https://pubmed.ncbi.nlm.nih.gov/11029010/

(14)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5198508/

(15)https://pubmed.ncbi.nlm.nih.gov/10799377/

(16)https://www.nature.com/articles/pr199186.pdf?origin=ppub

(17)https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-0412.1999.780902.x#:~:text=The%20demand%20for%20absorbed%20iron,12%E2%80%9318%20mg%2Fday.

(18)https://pubmed.ncbi.nlm.nih.gov/20001632/

(19)https://www.ncbi.nlm.nih.gov/books/NBK526131/

(20)https://www.nhs.uk/start4life

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