Iron is needed for the formation of heme, which is a part of haemoglobin (a protein found in red blood cells which transports oxygen to all tissues); but it has several other key bodily functions.
This nutrient can be found in the form of heme iron (usually seen in animal products) or non-heme iron (this form of iron is made by plants).
The National Institutes of Health's Recommended Dietary Allowances (RDAs) for Iron:
*Adequate Intake (AI)
Athletes/physically active people and women with high menstrual losses may require more iron than the general population.
The Institute of Medicine suggests that vegetarians may require 1.8 times more iron than the recommended levels and they suggest that vegans may require even more1. It's possible that long-term adaptation to plant-based diets may increase one's ability to absorb non-heme iron (but this has not been studied as far as I know).
Vegans with low levels of ferritin and iron should certainly aim for intakes higher than the RDA.
It is important to note that iron deficiency or iron deficiency anaemia is not only linked with insufficient intakes, but also with increased losses (through bleeding): consequently, low levels of iron should be reported to your doctor.
Examples of animal-free sources of iron:
(Source: https://fdc.nal.usda.gov/)
The bioavailability of non-heme iron is lower compared to heme iron. I advise consuming iron-rich foods with a source of vitamin C, as this may enhance absorption2. Fermentation, soaking and germination also increases iron bioavailability through releasing it from bonds with phytic acid3,4.
Polyphenol-rich beverages (e.g., teas, cocoa, coffee) when consumed with meals can inhibit iron absorption5. Calcium supplementation was also shown to reduce iron absorption but it may be a short duration effect with a subsequent adaptation without a negative impact on haematological status6.
A low-dose supplement is an option for those that struggle to meet the RDA. Discuss this with your doctor first.
References:
1. https://www.nap.edu
2. Hurrell, R. and Egli, I., 2010. Iron bioavailability and dietary reference values. The American journal of clinical nutrition, 91(5), pp.1461S-1467S. (https://academic.oup.com)
3. Afify, A.E.M.M., El-Beltagi, H.S., Abd El-Salam, S.M. and Omran, A.A., 2011. Bioavailability of iron, zinc, phytate and phytase activity during soaking and germination of white sorghum varieties. Plos one, 6(10), p.e25512. (https://journals.plos.org)
4. Proulx, A.K. and Reddy, M.B., 2007. Fermentation and lactic acid addition enhance iron bioavailability of maize. Journal of agricultural and food chemistry, 55(7), pp.2749-2754.
5. Hurrell, R.F., Reddy, M. and Cook, J.D., 1999. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. British Journal of Nutrition, 81(4), pp.289-295.
6. Lönnerdal, B., 2010. Calcium and iron absorption—mechanisms and public health relevance. International Journal for Vitamin and Nutrition Research, 80(4), p.293.
