A prevalent concern regarding vegan diets revolves around whether they adequately supply the body with essential vitamins and minerals. Many advocates assert that a whole-food, plant-based diet can effortlessly fulfill all daily nutrient needs. Some proponents even suggest that vegans should forgo all supplements altogether. While these recommendations may come from a place of good intentions, they can potentially lead to more harm than benefit.

Here, we explore seven critical nutrients that might require supplementation for those following a vegan diet.

1. Vitamin B12

Foods that are often highlighted for their rich vitamin B12 content encompass unwashed organic produce, mushrooms cultivated in B12-rich soils, nori, spirulina, chlorella, and nutritional yeast. Interestingly, some individuals suggest that vegans who consume a sufficient variety of appropriate plant foods do not need to be overly concerned about vitamin B12 deficiency. However, this assertion lacks scientific backing.

Research indicates that while anyone can experience low vitamin B12 levels, vegetarians and especially vegans face a heightened risk of deficiency. This concern becomes particularly pronounced for vegans who do not incorporate any vitamin B12 supplements into their diet. Vitamin B12 is vital for numerous bodily functions, including protein metabolism and the production of red blood cells that transport oxygen. Additionally, it plays an essential role in maintaining the health of the nervous system.

A deficiency in vitamin B12 can result in anemia and damage to the nervous system, along with increased risks of infertility, bone issues, and heart disease. The recommended dietary allowance is set at 2.4 mcg for adults, 2.6 mcg for pregnant individuals, and 2.8 mcg during breastfeeding.

The only scientifically validated method for vegans to meet these nutritional requirements is through the consumption of B12-fortified foods or the intake of a vitamin B12 supplement. Common sources of fortified foods include plant-based milks, soy products, breakfast cereals, and nutritional yeast.

While some plant foods appear to have a naturally occurring form of vitamin B12, there remains an ongoing debate regarding whether this form is biologically active in humans. Furthermore, there is no scientific evidence to support the notion that unwashed organic produce can be relied upon as a consistent source of vitamin B12. Nutritional yeast, while a popular choice, contains vitamin B12 only when fortified. It’s worth noting that vitamin B12 is sensitive to light and may degrade if purchased or stored in transparent plastic bags. To enhance absorption, it’s crucial to consume vitamin B12 in smaller doses. Therefore, if you eat it less frequently, you will need to consume more at one time.

This is why vegans who cannot attain the recommended daily intake through fortified foods should consider taking a daily supplement of 25–100 mcg of cyanocobalamin or a weekly dose of 2,000 mcg. For those hesitant about supplementation, it may be comforting to have their blood levels of vitamin B12 assessed before proceeding.

Moreover, the capacity to absorb vitamin B12 diminishes with age. Consequently, the Institute of Medicine advises that individuals over the age of 51, regardless of dietary choices, should contemplate incorporating fortified foods or a vitamin B12 supplement into their regimen. Ensuring adequate vitamin B12 intake is crucial for all vegans. The most reliable approach to achieve this is through the consumption of fortified foods or by taking a vitamin B12 supplement.

2. Vitamin D

Vitamin D is a crucial fat-soluble vitamin that plays a significant role in enhancing the absorption of calcium and phosphorus from the digestive system. This vitamin goes beyond just bone health; it also affects numerous bodily functions, including immune system regulation, mood stabilization, memory enhancement, and muscle recovery.

The recommended daily allowance (RDA) for vitamin D is set at 600 IU (15 mcg) for both children and adults. However, older adults, as well as pregnant or lactating women, are advised to increase their intake to 800 IU (20 mcg) per day. Notably, some research indicates that the actual daily requirements may be significantly higher than the current RDA.

Unfortunately, very few foods are naturally rich in vitamin D, and even fortified foods often fall short of meeting daily needs. This deficiency is observed globally, affecting both vegans and omnivores. Moreover, apart from dietary sources, vitamin D can be synthesized through sun exposure. Most individuals can produce sufficient vitamin D by spending just 15 minutes in the sun at midday when solar intensity is at its peak, provided they do not use sunscreen and expose a majority of their skin. However, certain groups, including older adults, individuals with darker skin tones, and those residing in northern latitudes or colder regions, may struggle to synthesize adequate amounts of vitamin D due to limited sun exposure.

Furthermore, due to the harmful effects of excessive UV radiation, many dermatologists caution against relying solely on sun exposure for vitamin D optimization. For vegans, a practical approach to ensure sufficient vitamin D levels involves having their blood tested regularly. If they are unable to obtain adequate levels through fortified foods and sunlight, considering a daily vitamin D2 or vegan vitamin D3 supplement is advisable.

While vitamin D2 may suffice for most individuals, research suggests that vitamin D3 might be more effective in elevating blood levels of this essential vitamin. Ultimately, vitamin D deficiency poses challenges for both vegans and omnivores. Therefore, vegans who find it difficult to maintain normal blood levels through diet and sun exposure should seriously contemplate supplementing.

3. Long-chain Omega-3 Fatty Acids

Omega-3 fatty acids are classified into two distinct categories:

• Essential Omega-3 Fatty Acids: The only essential omega-3 fatty acid is alpha-linolenic acid (ALA), which must be obtained solely through dietary sources.
• Long-Chain Omega-3 Fatty Acids: This group comprises eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are not deemed essential since the body can synthesize them from ALA.

Long-chain omega-3 fatty acids are crucial for the structural integrity of your brain and eyes. Maintaining adequate dietary levels appears vital for brain development and may help mitigate the risk of inflammation, depression, breast cancer, and attention deficit hyperactivity disorder (ADHD).

Rich sources of ALA include flax seeds, chia seeds, walnuts, hemp seeds, and soybeans (soya). In contrast, EPA and DHA are predominantly found in animal-derived products, particularly fatty fish and fish oil. Theoretically, sufficient ALA intake should sustain adequate levels of EPA and DHA; however, studies indicate that the conversion rate of ALA to EPA could be as low as 5-10%, and the conversion to DHA might range between 2-5%.

Moreover, research has consistently demonstrated that vegetarians and vegans exhibit blood and tissue concentrations of EPA and DHA that can be as much as 50% lower than those of omnivores. Most healthcare professionals concur that a daily intake of 200-300 mg is generally sufficient for health. For vegans, achieving this recommended intake can be accomplished through supplementation with algae oil.

Furthermore, reducing omega-6 fatty acids intake from oils such as corn, safflower, sunflower, and sesame, while ensuring adequate consumption of ALA-rich foods, may enhance EPA and DHA levels further. Given the tendency for vegans to have lower blood and tissue levels of long-chain omega-3 fatty acids, they may particularly benefit from EPA and DHA supplementation.

4. Iron

Iron is an essential nutrient crucial for synthesizing new DNA and producing red blood cells. It plays a vital role in transporting oxygen throughout the body and is integral for energy metabolism. A deficiency in iron can result in anemia, leading to symptoms such as fatigue and a weakened immune system.

The Recommended Dietary Allowance (RDA) for iron is 8 mg for adult men and post-menopausal women, while it rises to 18 mg per day for adult women. Pregnant women are advised to aim for a higher intake of 27 mg daily. This nutrient exists in two forms: heme iron, which is typically sourced from animal products, and non-heme iron, which can be obtained from plant-based foods.

Heme iron is absorbed more efficiently by the body compared to non-heme iron, prompting recommendations for vegans to consume 1.8 times the standard RDA to meet their needs. However, further research is required to determine if such elevated intakes are necessary. For those on a vegan diet experiencing low iron levels, increasing the intake of iron-rich foods is advisable. This includes options like cruciferous vegetables, beans (rajma), peas, dried fruits, nuts, and seeds. Additionally, iron-fortified products such as cereals, enriched breads, and certain plant milks can contribute significantly.

To enhance iron absorption, cooking with cast-iron cookware, steering clear of tea or coffee during meals, and pairing iron-rich foods with sources of vitamin C can be beneficial. The most effective way to ascertain if iron supplements are required is to have hemoglobin and ferritin levels evaluated by a healthcare professional.

Excessive iron supplementation can be detrimental, potentially damaging cells and hindering the absorption of other essential minerals. High levels of iron may even lead to severe health issues such as convulsions, organ failure, or coma, and can be fatal in extreme cases. Therefore, it is advisable to avoid supplementation unless absolutely necessary. Vegans who find it challenging to meet their iron requirements through diet alone should consider incorporating fortified foods or taking supplements. Nonetheless, it's crucial to be cautious, as excessive iron intake can pose health risks, and supplements are not universally recommended.

5. Calcium

Calcium is an essential mineral required for maintaining strong bones and teeth. Beyond its structural role, it is crucial for muscle function, nerve signaling, and overall heart health. The Recommended Dietary Allowance (RDA) for calcium stands at 1,000 mg per day for the majority of adults, rising to 1,200 mg daily for those over the age of 50.

Plant-based sources rich in calcium include bok choy, kale, mustard greens, turnip greens, watercress, broccoli, chickpeas, calcium-set tofu, and various fortified plant milks or juices. Nevertheless, research consistently indicates that many vegans struggle to meet their calcium needs adequately. A common assertion within the vegan community is that their calcium requirements are lower than those of omnivores, as they do not rely on this mineral to balance the acidity resulting from a meat-heavy diet.

Further studies are necessary to determine how plant-based diets influence daily calcium requirements. Nonetheless, evidence suggests that vegans who consume less than 525 mg of calcium daily are at a heightened risk of experiencing bone fractures. Consequently, it is highly recommended that all vegans strive to reach the RDA, ensuring they intake a minimum of 525 mg of calcium each day. If this cannot be accomplished through food or fortified options alone, supplements should be considered. Vegans lacking adequate dietary calcium should contemplate a daily supplement, particularly those who find themselves consuming less than 525 mg per day.

6. Zinc

Zinc is an essential mineral that plays a vital role in metabolism, supports immune function, and aids in the repair of body cells. A deficiency in zinc can result in various health issues, including developmental delays, hair loss, gastrointestinal distress, and slower wound healing processes.

The recommended dietary allowance (RDA) for zinc ranges from 8 to 11 mg per day for adults, increasing to 11 to 12 mg for pregnant women and 12 to 13 mg for those who are lactating. While zinc is found in some plant-based foods, the absorption of this mineral can be hindered by the presence of phytates, leading to the recommendation that vegetarians should aim for an intake of 1.5 times the standard RDA.

Although not all vegans exhibit low levels of zinc in their blood, a comprehensive review of 26 studies indicated that vegetarians — particularly vegans — generally have lower zinc intakes and slightly reduced blood zinc levels compared to those who consume omnivorous diets. To optimize your zinc consumption, it is beneficial to incorporate a diverse array of zinc-rich foods throughout your meals, such as whole grains, wheat germ, tofu, sprouted breads, legumes (dal), nuts, and seeds. Enhancing zinc absorption can be achieved by soaking nuts, seeds, and legumes overnight, ensuring adequate protein intake, and including fermented foods like tempeh and miso in your diet. For vegans who are apprehensive about their zinc levels or those experiencing deficiency symptoms, considering a daily supplement of zinc gluconate or zinc citrate that provides 50–100% of the RDA may be advantageous.

For individuals who find it challenging to meet the zinc RDA through food sources, the priority should be on increasing the consumption of zinc-rich ingredients. Those identified with low blood zinc levels may benefit from incorporating a daily supplement into their routine.

7. Iodine

Ensuring an adequate intake of iodine is vital for maintaining a healthy thyroid, which plays a significant role in regulating your metabolism. A deficiency in iodine during pregnancy and the early stages of infancy can lead to irreversible cognitive impairments, highlighting the importance of this nutrient during critical developmental periods.

For adults, a lack of sufficient iodine can result in hypothyroidism, which manifests through various symptoms, including fatigue, dry skin, numbness or tingling in the extremities, memory issues, feelings of depression, and unintended weight gain. Notably, individuals following a vegan diet may be at a heightened risk for iodine deficiency, with studies indicating that their blood iodine levels can be as much as 50% lower compared to those of vegetarians.

The recommended dietary allowance (RDA) for adults stands at 150 mcg of iodine per day. Pregnant women should aim for a higher intake of around 220 mcg daily, while breastfeeding mothers are advised to increase their consumption to 290 mcg per day to support their nutritional needs.

The iodine content found in plant-based foods largely depends on the iodine levels present in the soil where they are cultivated. For example, produce grown in proximity to the ocean typically boasts higher iodine concentrations. Foods known to be rich in iodine include iodized salt, seafood, seaweed (nori), and dairy products, which absorb iodine from the cleaning solutions used on cows and farming equipment. A mere half teaspoon (approximately 2.5 ml) of iodized salt can effectively fulfill your daily iodine requirements.

Vegans who prefer not to use iodized salt or consume seaweed multiple times a week should contemplate the option of iodine supplementation to ensure their nutritional needs are met. Iodine is crucial for optimal thyroid function and metabolic processes; therefore, vegans lacking sufficient iodine sources should seriously consider incorporating an iodine supplement into their dietary regimen.

The Bottom Line

A thoughtfully designed vegan diet can effectively meet your nutritional requirements. However, there are specific nutrient needs that might be challenging to fulfill solely through plant-based foods and fortified options. This holds particularly true for vital nutrients such as vitamin B12, vitamin D, and long-chain omega-3 fatty acids. For vegans who find it difficult to achieve their dietary targets through food alone, considering supplements becomes essential. Nevertheless, it is advisable to consult with your healthcare provider before embarking on a new supplement regimen to ensure safety and efficacy.