Introduction

Are you plant-based or vegan and experiencing unexplained fatigue, weakness, or other unsettling symptoms? If so, you're not alone. Many individuals following vegan or vegetarian diets may unknowingly be at risk of nutrient deficiencies that can impact overall well-being. It’s crucial to understand the potential risks associated with eliminating meat and dairy products from your diet and how to address them effectively. Here, we'll explore the common symptoms of vegan nutrient deficiencies—specifically vitamin B12, iron, omega-3s, and vitamin D—providing both insights and practical strategies for maintaining optimal nutrient levels.

The Rise of Plant-Based Diets and Common Deficiencies

According to a 2023 survey, approximately 5% of the United States population identifies as vegetarian, and an increasing number are adopting fully plant-based or vegan lifestyles (1). Millions are opting for this dietary lifestyle due to its health and environmental benefits, though these dietary choices can also pose challenges in meeting our body’s nutrient needs, which can lead to deficiencies that can have detrimental effects if not treated. Four of the most common nutrient deficiencies and their symptoms that can occur on vegan and vegetarian diets include:

1. Vitamin B12

Most plant-based eaters are well aware that vitamin B12 deficiency is the most common deficiency when vegan or vegetarian, and many choose to take a B12 supplement upon switching their diet. Although the actual percentages could be different based on age and demographic, one study found that 60% of participants following a vegetarian diet were deficient in vitamin B12 (2). The question is, why is deficiency so common?

Vitamin B12 deficiency is so common because there is no reliable plant-based source of B12. In other words, it is really only found in animal products such as meat, fish, eggs, and dairy – foods that are eliminated when eating plant-based.

Vitamin B12 gets stored in the liver, so symptoms of deficiency, ranging from mild to severe, can take several years to develop (3). Common signs and symptoms include fatigue, shortness of breath, tingling sensations, memory problems, and mood changes. If left untreated, deficiency can lead to more severe symptoms such as neurological problems (4).

Reliable sources of vitamin B12 when plant-based include fortified foods and supplements. B12 can be found in fortified foods such as plant-based milk, breakfast cereals, meat substitutes, and nutritional yeast (5). If struggling to meet B12 requirements through diet alone, supplementation is a convenient and reliable option. For example, supplementing with an all-in-one complete vegan multivitamin such as the plant-based essentials is a great source of vitamin B12 for vegans.

If you’re interested in learning more about the science behind vitamin B12 and want to ensure you’re getting enough, read this journal club article all about Vitamin B12.

2. Iron

If you follow a plant-based diet, you likely also have a higher risk of iron deficiency, affecting approximately 10-30% of vegetarians and vegans in the United States (6). Iron deficiency is common largely due to the fact that plant-based sources of iron (non-heme iron) are less readily absorbed by the body than animal-based sources (heme iron). Non-heme iron is less bioavailable than heme iron due to the presence of compounds in plants such as phytic acid that block iron absorption by our bodies (7). Plant-based sources of iron (non-heme iron) include legumes, beans, spinach, and fortified cereals.

Iron plays a critical role in oxygen transport, energy production, and our immune system function (8). Deficiency can manifest as fatigue, dizziness, weakness, cold hands and feet, and pale skin.

Focusing on eating iron-rich plant foods or supplementing with iron can help reduce the chance of becoming iron deficient. Ferrous bisglycinate, one of the best supplemental forms of iron, is known to be gentle on the stomach and can be found in the plant-based essentials. Keep in mind that some iron supplements may cause side effects that can include stomach upset, nausea, constipation, or diarrhea. To minimize these effects, it is recommended to take iron-containing supplements with food.

3. Omega-3s

Plant-based eaters may struggle to obtain sufficient omega-3 fatty acids (DHA and EPA) as they are mainly found in cold-water fish, shellfish, and cod liver oil. While plant-based sources of omega-3s like flaxseeds and walnuts are available, vegans may struggle to meet their omega-3 needs due to the lower bioavailability of these nutrients in plants (9). The bioavailability is lower in plant foods because the omega-3 found in plants known as ALA needs to be converted to EPA and DHA to be used by the body, and this conversion is very inefficient (10). Deficiency can lead to symptoms such as dry skin and hair, joint pain and stiffness, mood changes, and poor cognitive function (11, 12, 13).

To prevent an omega-3 deficiency, focus on eating plant-based sources of omega-3s and consider supplementing with a vegan, algae-based omega-3 supplement. Algae naturally contains DHA and EPA and provides a source of these nutrients without the need for fish-derived products. An algae-based omega-3 supplement can be found in the plant-based essentials, an all-in-one vegan multivitamin.

4. Vitamin D

Recent studies suggest that around 40% of the United States population may have insufficient vitamin D levels, with plant-based individuals potentially at a higher risk. (14). This is because dietary sources of vitamin D are limited and relying solely on sun exposure is difficult. Vitamin D is synthesized by our bodies naturally after exposure to sunlight and supports optimal immune function, bone health, and aids in calcium absorption (15). Symptoms of vitamin D deficiency include fatigue, bone pain, muscle weakness, and an increased susceptibility to infections (16).

To boost vitamin D levels, spend some time outside during peak sunlight hours, typically midday. Additionally, incorporating fortified plant milks, fortified cereals, or taking a vitamin D supplement (especially during the winter months) can help increase vitamin D levels more reliably. Look for a supplement that uses vitamin D3, the form of vitamin D that is naturally produced in the body and is more bioavailable than other forms such as vitamin D2 (17) (vitamin D3 supplement can be purchased here).

Recognizing and Addressing Symptoms

Eating a balanced, well-planned, plant-based and vegan diet that incorporates a variety of nutrient-dense foods can help optimize your intake of essential vitamins and minerals to prevent serious deficiencies. Consulting a healthcare professional for regular blood tests when vegan or plant-based can be helpful to monitor nutrient levels and detect deficiencies early enough where they can still be treated. Based on individual needs, your doctor might recommend dietary adjustments or supplementation to address your specific deficiencies efficiently and effectively.

Conclusion

While plant-based and vegan diets offer substantial health and environmental benefits, they require careful planning to ensure you’re getting all the nutrients you need. Understanding the common nutrient deficiencies that can occur – such as vitamin B12, iron, omega-3s, and vitamin D – can help you make informed dietary choices and prioritize your health. Eating a well-rounded diet, incorporating fortified foods, and taking a vegan supplement when needed can minimize your risk of deficiency.

If you’re considering switching to a plant-based diet and you’re unsure if you should take the leap, read this post about the benefits of plant-based diets while addressing their risks.

References

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