Are you getting enough iron on a vegan diet?

Iron is a mineral and it’s a nutrient our body needs to carry out it’s many daily functions. Iron also plays a major role in the development and function of our red blood cells. It is what allows our red blood cells to properly carry oxygen, so that our body’s tissues and organs can be supplied with oxygen rich blood. It also plays a crucial role in cognitive development, and for that reason iron needs are actually increased during pregnancy and certain periods of childhood. When our body’s iron stores are insufficient that results in a condition known as iron deficiency anemia. Common symptoms of iron deficiency anemia are fatigue despite adequate sleep, cold hands and feet, difficulty concentrating, poor appetite, shortness of breath, and a desire for eating non-nutritive things such as chewing on ice cubes [8].

We can get iron from a variety of food sources, however; the body absorbs iron in different amounts depending upon the food source. There are two types of iron, heme and nonheme, and depending on the food source is how you can differentiate which is which. Heme iron is found only in animal foods and is absorbed very efficiently by the body. Examples of foods rich in heme iron are sardines, oysters, beef, chicken, turkey and eggs. Although the body absorbs heme iron very efficiently, there’s a caveat to that which I will return to in just a moment. Non-heme iron is found primarily in plants because plants have only non-heme iron and they are not able to produce heme iron. Foods rich in non-heme iron are white beans, raw cacao, moringa powder, lentils, spinach, tofu, and chickpeas. Animal foods can contain both heme and nonheme iron, however; they have more of the former than the later. Non-heme iron is absorbed less efficiently by the body. Even though our bodies absorb less of the nonheme iron, when we take a closer look we start to see that it’s actually nature’s divine design working in our favor.

Let’s return to the caveat I mentioned earlier about heme iron. You may have likely at some point in life heard the saying that, “too much of a good thing can be a bad thing”, well that very well describes the caveat with heme iron. Yes, our body absorbs it quite efficiently compared to non-heme iron, but that leaves the potential for us to take in too much. As discussed earlier iron is quite vital to our health, but too much iron actually acts a “prooxidant” in the body. This means that it can cause oxidative stress and unnecessary inflammation in the body. Unnecessary inflammation in the body, especially chronic, low grade, is associated with - you guessed it - chronic diseases. Some examples of diseases linked with excess iron are type 2 diabetes [6], heart disease [2], stroke [1], and cancers such as ovarian and liver cancer [5]. The more a person consumes meat, poultry, and fish the more likely they are to develop these chronic diseases associated with excess iron. Although our body does a great job of taking in the iron, it’s much less efficient at releasing excess amounts taken in [5].

You might be wondering about non-heme iron and whether or not it has these same risks; well, it doesn’t. Foods rich in non-heme iron contain certain naturally occurring substances known as “anti-nutrients” which decrease the absorption of iron, thereby preventing us from absorbing too much. Personally, I interpret this as nature’s divine design working in our favor. With this in mind, it makes sense that intake of non-heme iron has not been found to be associated with the chronic diseases I mentioned above (type 2 diabetes, stroke, heart disease, cancer). In fact, frequent intake of plant based foods that are rich in non-heme iron (ex: beans, lentils, dark green leafy vegetables) are associated with decreased chances of developing these diseases that excess heme iron is known to make us susceptible to.

These naturally occurring substances are called anti-nutrients because they interfere with the absorption of various nutrients, such as calcium, iron, and zinc. Different kinds of anti-nutrients are naturally occurring in many different plant based foods (ex: broccoli, beans, whole grains, nuts, seeds, and teas), but don’t let the word “anti-nutrient” scare you away from eating these health promoting foods! Although it might not sound as great for us, they do serve a purpose in protecting the plant from succumbing to infections and pests before harvest [9].

Don’t throw the vegan diet out the window just yet in the name of anti-nutrients, because there are things we can do (some of which you might unknowingly already be doing) to reduce the amount of anti-nutrients and increase non-heme iron absorption. Beans and lentils are iron rich foods and also rich in phytates, a type of anti-nutrient. Soaking, fermenting, or sprouting these foods can reduce the phytate content. Some examples of this are tempeh (fermented soybean), or simply soaking beans before cooking them. Additionally, anytime you have a plant based source of iron, pair it with vitamin C in order to increase the absorption. Some ideas you can try are cooking white beans in a tomato based sauce, or adding mandarin orange pieces on top of a spinach salad. Also, breakfast cereals and non dairy milks can potentially be fortified with some iron as well.

If you have been diagnosed with iron deficiency anemia, you will likely need to take a supplement to correct the deficiency. Once it’s corrected, you should then be able to suffice with dietary intake. As always, follow the guidance of your doctor first and foremost. The tables below list the daily iron needs of different age groups, along with foods and their iron content. The best way to ensure that your iron intake is adequate on a vegan diet, is to regularly consume beans, lentils, and dark green leafy vegetables, and to as often as you can pair them with foods that are rich in vitamin C.

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References

[1]. Kaluza, J., Wolk, A., & Larsson, S. (2013). Heme Iron Intake and Risk of Stroke. Stroke, 44(2), 334-339. doi: 10.1161/strokeaha.112.679662

[2]. Fang, X., An, P., Wang, H., Wang, X., Shen, X., & Li, X. et al. (2015). Dietary intake of heme iron and risk of cardiovascular disease: A dose–response meta-analysis of prospective cohort studies. Nutrition, Metabolism And Cardiovascular Diseases, 25(1), 24-35. doi: 10.1016/j.numecd.2014.09.002

[3]. Gozzelino, R., & Arosio, P. (2016). Iron Homeostasis in Health and Disease. International Journal Of Molecular Sciences, 17(1), 130. doi: 10.3390/ijms17010130

[4]. Etemadi, A., Sinha, R., Ward, M., Graubard, B., Inoue-Choi, M., Dawsey, S., & Abnet, C. (2017). Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: population based cohort study. BMJ, j1957. doi: 10.1136/bmj.j1957

[5]. Toyokuni, S. (2009). Role of iron in carcinogenesis: Cancer as a ferrotoxic disease. Cancer Science, 100(1), 9-16. doi: 10.1111/j.1349-7006.2008.01001.x

[6]. Bao, W., Rong, Y., Rong, S., & Liu, L. (2012). Dietary iron intake, body iron stores, and the risk of type 2 diabetes: a systematic review and meta-analysis. BMC Medicine, 10(1). doi: 10.1186/1741-7015-10-119

[7]. Office of Dietary Supplements - Iron. (2020). Retrieved 19 October 2020, from https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/

[8]. Iron deficiency anemia - Symptoms and causes. (2020). Retrieved 19 October 2020, from https://www.mayoclinic.org/diseases-conditions/iron-deficiency-anemia/symptoms-causes/s yc-20355034

[9]. Are anti-nutrients harmful?. (2020). Retrieved 19 October 2020, from https://www.hsph.harvard.edu/nutritionsource/anti-nutrients/#:~:text=Oxalates%20in%20gr een%20leafy%20vegetables,interfere%20with%20normal%20nutrient%20absorption.

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