In recent years, the shift towards plant-based diets has gained considerable momentum as many choose to embrace the health benefits of consuming more fruits, vegetables, grains, and legumes. While there’s no denying the positive impact of plant-based eating on overall health and wellbeing, it’s essential to understand its implications for specific nutrient deficiencies. Iron and vitamin B12 (also known as cobalamin) are of particular concern and both are crucial for red blood cell formation.

Iron deficiency anemia and vitamin B12 deficiency anemia are two types of anemia that occur when the body lacks enough of these essential nutrients. Anemia - which is a condition where the red blood cells or hemoglobin concentration is lower than normal - can lead to symptoms like fatigue, weakness, shortness of breath, and even more severe health complications if left untreated. Therefore, it’s important to explore how plant-based diets may influence the risk of developing these types of anemia.

Iron Deficiency and Anemia

First, let’s talk about iron deficiency. Iron is abundant in various animal products such as red meat, poultry, and fish in its “heme” form, which allows individuals who consume animal products to meet their iron needs. However, for those following a plant-based diet, obtaining enough iron may require a bit more attention to dietary choices. Plant-based sources of iron include leafy greens like spinach and kale, legumes like lentils and beans and some fortified cereals. These sources provide “non-heme” iron, which is not as readily absorbed by the body as heme iron. In light of this issue, research has been done to assess how plant-based diets may affect iron levels and overall health.

Several studies that assessed iron intake in omnivores and individuals who follow a plant-based diet found deceased levels of iron in vegans compared to omnivores. A German study by Dawczynski et al. (2022) measured overnight ferritin and hemoglobin levels in omnivores, flexitarians, vegetarians and vegans. Ferritin - which is a blood protein that contains iron and indicates iron levels in the body - was found to be 2.5 times higher in omnivores compared to individuals following other dietary patterns. Although vegans had the lowest ferritin levels, this did not necessarily translate to being iron deficient. In fact, researchers found that omnivores men and vegan women had the highest prevalence of iron deficiency anemia. Therefore, although there is evidence of low iron stores in vegans, this does not necessarily indicate a higher risk of iron deficiency anemia compared to other dietary patterns. Additional research is needed to fully understand the relationship between a plant based diet and iron deficiency anemia.

Vitamin B12 Deficiency and Anemia

On the other hand, vitamin B12 is predominantly found in animal products, making it a potential concern for individuals following strict plant-based diets. Vitamin B12 plays a crucial role in red blood cell formation and nerve function, so deficiency can have serious consequences

While some plant-based foods are fortified with vitamin B12 such as nutritional yeast, certain cereals, and plant-based milk, research reveals that individuals following a plant-based diet and not supplementing vitamin B12 are at an increased risk of deficiency. Research by Obeid et al. (2002), showed that vegans had lower vitamin B12 stores in tissues compared to vegetarians and omnivores. However, it is unclear how often these deficiencies result in anemia. Regardless, Obeid et al.’s (2002) findings emphasize the importance for those following a plant-based diet to be diligent in ensuring they consume enough vitamin B12.

What Can I Do to Prevent Deficiency Anemias?

Here are some tips to help you increase your iron and vitamin B12 absorption/intake:

Pair foods high in iron with vitamin C. For example, instead of having that spinach salad with a glass of wine, you can substitute the wine for some orange juice. Vitamin C helps your body absorb non-heme iron better.

Consider cooking foods in a cast iron skillet/cookware. This also helps to increase your iron intake since some iron will make its way into your food.

Boost your vitamin B12 intake by consuming fortified foods or taking supplements. Look for products like plant-based milks or cereals that are enriched with vitamin B12.

The key takeaway here is that while plant-based diets offer numerous health benefits, including reduced risk of chronic diseases like heart disease and diabetes, it’s important to be mindful of potential nutrient deficiencies (particularly iron and vitamin B12). By incorporating a variety of nutrient-rich plant foods into your diet and paying attention to sources of iron and vitamin B12, you can nourish your body while enjoying the benefits of plant-based eating. Remember, balance and variety are key to a nourished body and a thriving life!

If you are concerned that you may have a nutrient deficiency, please speak with your physician or a registered dietician

References

Dawczynski, C., Weidauer, T., Richert, C., Schlattmann, P., Dawczynski, K., & Kiehntopf, M. (2022). Nutrient intake and nutrition status in vegetarians and vegans in comparison to omnivores—the nutritional evaluation (NuEva) Study. Frontiers in Nutrition, 9, 819106. https://doi.org/10.3389/fnut.2022.819106

Obeid, R., Geisel, J., Schorr, H., Hübner, U., & Herrmann, W. (2002). The impact of vegetarianism on some haematological parameters. European Journal of Haematology, 69(5–6), 275–279. https://doi.org/10.1034/j.1600-0609.2002.02798.x

Somerville, M. (2024). Human Nutrition Lecture 12b [Powerpoint Slides]. Brightspace. https://dal.brightspace.com

Somerville, M. (2024). Human Nutrition Lecture 13a [Powerpoint Slides]. Brightspace. https://dal.brightspace.com

Wang, Y., Liu, B., Han, H., Hu, Y., Zhu, L., Rimm, E. B., Hu, F. B., & Sun, Q. (2023). Associations between plant-based dietary patterns and risks of type 2 diabetes, cardiovascular disease, cancer, and mortality—A systematic review and meta-analysis. Nutrition Journal, 22(1), 46. https://doi.org/10.1186/s12937-023-00877-2