What is iron?
Iron a key micronutrient and mineral responsible for various bodily processes such as transporting oxygen, formation of red blood cells, protein synthesis and muscle metabolism. It occurs in two forms in our body, ferrous (Fe2+) form in our cells and ferric (Fe3+) form out of our cells (1).
Our body cannot eliminate iron therefore the quantity of iron is measured by pairing the intestinal uptake and transfer of iron to the amount needed to replace losses of iron e.g., menstruation, and the quantity required for reproduction and growth. The amount of iron required from the diet is essential to meet the bodies requirement for iron (2).
statisitcs
Iron deficiency is one of the biggest nutritional deficiencies worldwide, the main cause of anaemia and one of the five leading causes of global disease burden.
The National Diet and Nutrition Survey showed that 54% of girls and 27% of women had iron intakes below the lower reference nutrient intake, this is insufficient for most individuals, as it depicts the level of intake that is likely to be adequate to meet the needs of only 2·5 % of the population (3).
Anaemia occurs when the haemoglobin levels fall below ‘normal’, resulting in tiredness, weakness and fatigue. It can be caused by many factors including inadequate iron intake in diet and absorption of nutrients, infections, gynae conditions, inflammation and chronic diseases and the most prevalent nutritional cause of anaemia is iron deficiency. Low B12 and folate can also cause anaemia. World Health Organisation (WHO) estimates that 40% of children 6–59 months of age, 37% of pregnant women, and 30% of women 15–49 years of age globally are anaemic (4).
iron and diet
Dietary iron occurs in two forms haem iron (animal sources) and non-haem (plant sources). Some of the richest sources of iron include vegetables, cereals, eggs, meat and fish and iron is also added to many foods in manufacturing known as food fortification and in supplement form.
Iron absorption can be affected by its bioavailability based on dietary and physiological factors. Iron is suggested to be best absorbed from haem iron, however non milk animal proteins can aid the absorption of non-haem iron and vitamin C also increases iron absorption from meals. Iron absorption can also be reduced by food containing compounds such as phytates, polyphenols and tannings (5).
Iron is a key nutrient that should be considered in a plant-based diet and eating a wide variety of foods such as green leafy vegetables, grains, nuts and beans. Supplementation should be considered if dietary sources are not being priorisited. Some studies have shown that dietary requirements for iron can be met with flexitarian, vegan and vegetarian diets made up of traditional or novel plant-based foods (6).
How much do we need?
Current recommendations for iron in the UK are 8.7mg a day for men aged 19 and over, 14.8mg a day for women aged 19-49 and 8.7mg a day for women aged 50 and over.
Many dietary surveys have shown that women are particularly high in iron deficiency and iron is required during phases of growth such as infancy, childhood, adolescence and pregnancy.
Your body has the ability to control how much iron you can absorb from your dietary intake, and it can consume more iron from food when required e.g., growth and pregnancy (7).
There is such thing as too much of a good thing so be weary when supplementing iron in high doses without professional advice.
SUMMARY
Strategies to optimise iron supplementation include supplementation, food fortification and diet diversity consuming a variety of iron rich foods including red meats, fish, poultry, pulses, legumes, dark green vegetables, nuts and seeds (8).
Remember that some foods containing phytates and phenols can reduce non haem iron absorption e.g., wholegrains and cereals as they contain fibre, don’t cut them from your diet but ensure you eat them at different times of the day (9).
Eating a meal combining haem and non-haem iron can increase the amount of non-haem iron absorbed by the body.
Whilst red meat provides a reputable source of haem iron and other key nutrients there is a drive to reduce red meat consumption for environmental and health reasons and according to WCRF we should aim to eat no more than about 1-2 portions a week of red meat as it is associated with increased risk of some cancers such as colorectal and bowel cancer (10).
On a positive note, there is a large variety of plant-based iron rich foods along with fortified foods and supplements to meet our iron requirements.
Include more variety in your diet to optimise your nutrition, see a registered nutritionist/ dietitian if you want support with your diet and if you are experiencing tiredness/fatigue see your GP to check your iron levels.
References
- https://www.britishcardiovascularsociety.org/resources/editorials/articles/iron-therapy-heart-failure-evidence-so-far
- https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/339309/SACN_Iron_and_Health_Report.pdf
- https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/iron-deficiency-anaemia-experiences-and-challenges/573389D3356312E1F70304A2B8867A48
- https://www.who.int/health-topics/anaemia#tab=tab_1.
- https://www.researchgate.net/publication/7906234_Iron_nutrition_in_the_UK_Getting_the_balance_right
- https://www.frontiersin.org/articles/10.3389/fanim.2023.1142252/full
- https://www.bda.uk.com/resource/iron-rich-foods-iron-deficiency.html
- https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/iron-deficiency-anaemia-experiences-and-challenges/573389D3356312E1F70304A2B8867A48
- https://www.hriuk.org/health/your-health/nutrition/managing-iron-levels
- https://www.wcrf.org/diet-activity-and-cancer/cancer-prevention-recommendations/limit-red-and-processed-meat/#:~:text=What%20is%20red%20meat%3F,%2C%20mutton%2C%20horse%20and%20go
Contribution by Registered Nutritionist, Gopi Chandratheva
