Top 8 Nutrients of Concern and Supplements for Vegans and Vegetarians

The popularity of vegan, plant-based diets is at an all-time high; approximately 2% of North Americans report following a vegan diet. (15)(29) If you follow a vegan diet, which completely excludes all animal products such as meat, poultry, fish, eggs, honey, and dairy, you may be wondering if certain nutrients are lacking in your diet. A healthy, well-planned vegan or vegetarian diet can be achieved through eating an abundance of vegetables, fruits, whole grains, and plant-based proteins, such as beans, legumes, nuts, and seeds. (30) However, your healthcare practitioner may suggest supplements to ensure nutrient adequacy for optimal health. Keep reading to learn more about the top supplements for vegans and vegetarians. Vegan and vegetarian diets are rich in fiber and antioxidants; however, they may lack several essential nutrients such as iron, zinc, and omega-3 fatty acids.

Top 8 nutrients of concerns and supplements for vegans

Vegans should ensure they are consuming adequate amounts of the following nutrients. Plant-based diets are widely considered to promote good health, and research shows that following a vegan diet may provide a number of health benefits, including protection against certain cancers and lower risk of cardiovascular mortality. (5) However, many key nutrients needed by the body, such as vitamin B12, iron, and zinc, are predominantly found in animal foods. Planning is key to ensure intake of these nutrients and supplementation may be recommended to fill nutritional gaps.

Protein

Protein is an essential macronutrient that is made up of components called amino acids. Protein is broken down into amino acids during digestion, which are then used for various bodily functions such as muscle building and hormone synthesis. (31) The Dietary Reference Intake (DRI) for protein intake is 0.8 g/kg of body weight per day. For example, someone who weighs 180 lbs (81.8 kg) would need to consume about 65 g of protein per day (0.8 g x 81.8 kg = 65 g/day). However, the DRI for protein is not necessarily optimal for all individuals as protein needs vary depending on your age, body size, and activity level. (16) For example, someone who engages in moderate physical activity may require 1.3 g of protein per kg of body weight per day, whereas someone who engages in intense physical activity may require 1.6 g of protein per kg of body weight per day. (31) It’s essential to consume enough protein on a daily basis since the body does not store protein the way it stores carbohydrates and fats. (16) As a result, meeting your protein requirements on a vegan diet requires some additional planning, but it’s not impossible. Focus on consuming various plant-based protein sources with each meal. Examples include:

• Beans
• Lentils
• Nuts and seeds
• Peas
• Soy (e.g., tempeh, tofu)

Protein is found in many plant-based foods. (25) Although many plant-based foods contain protein, they may not be as bioavailable as animal-based protein sources. For this reason, vegans may need to increase their protein requirements beyond the general recommendations for omnivores. One study noted that vegans should consider increasing their protein intake from 0.8 g/kg to 1 g/kg of body weight to account for the lower protein digestibility of plant-based foods. (13)

Vitamin B12

Vitamin B12 is a water-soluble vitamin that plays a vital role in growth and development, central nervous system function, red blood cell formation, and DNA synthesis. (21) Vegans are at a higher risk of developing a vitamin B12 deficiency than omnivores because naturally-occurring B12 only exists in animal-sourced foods, such as meat, fish, seafood, and dairy. Some foods are fortified with vitamin B12, such as breakfast cereals, non-dairy milk alternatives, and nutritional yeast. (21)

Did you know? Nutritional yeast is an inactive yeast with a cheese-like flavor that can be sprinkled on pasta, popcorn, salads, or other savory foods.

Vitamin B12 deficiency can have detrimental, long-term health effects such as irreversible neurological damage. (21) Many vegans and vegetarians are advised to take a daily B12 supplement to avoid or correct deficiency. (28)

Did you know? Three naturally-occurring forms of B12, methylcobalamin, adenosylcobalamin, and hydroxycobalamin, have superior bioavailability to cyanocobalamin, a synthetic form of vitamin B12 commonly added to fortified foods. (26)

Vitamin D

Vitamin D is a fat-soluble vitamin that plays a role in bone, immune, heart, and mental health. We can get vitamin D from multiple sources, including the sun, foods, and supplements. When skin is exposed to the sun, ultraviolet (UV) rays react with a cholesterol precursor in the skin, creating vitamin D3. (23) Dietary sources of vitamin D are limited and primarily include animal-sourced foods such as cod liver oil, salmon, trout, eggs, and fortified dairy products. (23) Plant-based sources of vitamin D and their percent daily values (DV) include:

• Mushrooms exposed to ultraviolet (UV) light – 46% DV per ½ cup
• Fortified non-dairy beverages (e.g., almond or soy milk) – 13 to 18% DV per 1 cup
• Fortified breakfast cereals – 10% DV per serving* (23)

*Many fortified breakfast cereals are not vegan as they may contain vitamin D3 (cholecalciferol) made from lanolin (sheep’s wool). (3)

Did you know? Vitamin D deficiency is common among both vegans and omnivores due to limited sun exposure. In fact, vitamin D deficiency affects approximately 40% of individuals living in North America. (7)(12)

If you don’t consume enough vitamin D sources or you spend limited time in the sun, your integrative healthcare practitioner can order a simple blood test to assess your vitamin D status. If your vitamin D status is less than optimal, they may suggest a vitamin D supplement. (23)

Calcium

As the most abundant mineral in the body, calcium is essential for many functions, including structural and circulatory health. (17) The best sources of calcium include yogurt, calcium-fortified orange juice, cheese, sardines, and tofu. Since most sources of calcium are animal-based food sources, it can be challenging for vegans to reach their daily calcium needs. (17) Consequently, they may require additional calcium through supplementation if advised by a practitioner. (17) Plant-based sources of calcium include:

• Tofu – 19% DV per ½ cup
• Soybeans – 10% DV per ½ cup
• Spinach, boiled – 9% DV per ½ cup
• Turnip greens, boiled – 8% DV per ½ cup
• Kale, cooked – 7% DV per 1 cup
• Chia seeds – 6% DV per 1 tbsp (17)

Did you know? Approximately 98% of the calcium in your body is stored in the bones. (17)

Iodine

Iodine is a trace mineral and essential component of thyroid hormones. When iodine levels are low, the pituitary gland in the brain increases the secretion of thyroid-stimulating hormone (TSH) in order to sequester more iodine from the blood circulation and increase the production of thyroid hormones. Signs of insufficient iodine can include elevated TSH levels and goiter (enlarged thyroid). (18) Iodine is found in limited plant-based sources and is present mainly in animal foods, such as fish, seafood, eggs, and dairy products. Plant-based sources of iodine include:

• Seaweed, nori – 155% DV per 10 g
• Iodized table salt – 51% DV per ¼ tsp (18)

Unless you regularly consume seaweed or you cook with iodized table salt instead of specialty salts (e.g., sea salt, Himalayan salt, kosher salt), it’s likely that you’re not getting enough iodine in your diet. For this reason, you may benefit from an iodine supplement. (18) Due to its influence on thyroid function, it’s important only to take iodine supplements under the direction of your healthcare provider.

Did you know? Certain foods, known as goitrogens, can interfere with iodine uptake in the thyroid and worsen iodine deficiency. Foods high in goitrogens include soy, cassava, and cruciferous vegetables (e.g., broccoli, cauliflower). Goitrogens are not a cause for concern for most people; however, they can pose a problem if you don’t consume enough iodine. (18)

Iron

Iron is a constituent of hemoglobin, a protein that transports oxygen from the lungs to the tissues. Consuming enough iron is also essential for healthy cellular functioning, hormone synthesis, neurological development, and muscle metabolism. (19) Iron is found in various plant-based foods, including:

• White beans, canned – 44% DV per cup
• Dark chocolate, 45 to 69% cacao solids – 39% DV per 3 oz
• Lentils, boiled – 17% DV per ½ cup
• Spinach, boiled – 17% DV per ½ cup
• Tofu, firm – 17% DV per ½ cup
• Kidney beans, canned – 11% DV per ½ cup (19)

Although many plant-based foods contain iron, consuming these sources may not provide enough iron to meet daily recommendations. According to a 2018 meta-analysis, vegetarians are more likely to have low iron stores than omnivores. (10) Iron is available in two forms: heme, found in animal sources (e.g., oysters, beef liver, beef), and non-heme iron, found in plant sources. Heme iron is better absorbed and utilized by the body than non-heme iron from plant-based foods. (11) You can enhance iron bioavailability in your diet by cooking with cast-iron pans (9) and pairing iron-rich foods with sources of vitamin C (e.g., bell peppers, citrus fruits, broccoli), which can improve iron absorption. (22) Your practitioner can assess your iron stores by ordering a blood test. Do not take iron-containing supplements without instructions from your practitioner, as excess iron can lead to toxicity and other health concerns. (19)

Omega-3 fatty acids

Omega-3 fatty acids, which are found in various plant and animal foods such as fish, seafood, nuts, and seeds, are essential for brain, eye, cardiovascular, immune, and endocrine health. There are three main forms of omega-3 fatty acids: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). (20) ALA, found mainly in plant-based foods, converts to EPA and DHA in the body; however, the conversion of ALA to EPA and DHA is inefficient in humans, meaning that most EPA and DHA consumption is limited to marine sources. (20) Plant-based sources of omega-3 fatty acids include:

• Flaxseed oil – 7.26 g ALA per 1 tbsp
• Chia seeds – 5.06 g ALA per 1 oz
• English walnuts – 2.57 g ALA per 1 oz
• Flaxseed – 2.35 g ALA per 1 tbsp
• Edamame – .28 g ALA per ½ cup (20)

Studies have demonstrated that vegans and vegetarians have DHA concentrations up to 60% lower than omnivores who consume fish and seafood. (4) Considering the poor conversion rate of ALA to DHA, individuals consuming a vegan diet may benefit from an omega-3 supplement. Most commercially available omega-3 supplements are sourced from fish; however, algal-derived omega-3 supplements are suitable alternatives for vegans and vegetarians. According to a 2017 systematic review, algal-derived supplements significantly improved DHA concentrations in vegetarians. (4)

Did you know? Approximately 5 to 21% of ALA is converted to EPA and 0.5 to 9% to DHA. (1)(2)(5)(27)

Zinc

Zinc is an essential trace mineral that supports immune function, DNA synthesis, growth and development, and more. (24) According to a 2013 meta-analysis, zinc intake and serum zinc concentrations are significantly lower in individuals consuming a vegan diet than those eating animal products. (8) The most abundant sources of zinc include animal protein foods such as oysters, beef, crab, lobster, pork, and chicken. As a result, vegans and vegetarians may struggle to meet their daily nutritional needs through diet alone. (24) Zinc is found in some plant-based foods such as:

• Pumpkin seeds – 20% DV per 1 oz
• Cashews – 15% DV per 1 oz
• Chickpeas – 12% DV per ½ cup
• Almonds – 8% DV per 1 oz
• Kidney beans – 8% DV per ½ cup
• Green peas – 5% DV per ½ cup (24)

Similar to iron, zinc found in animal-based foods is more bioavailable and absorbed more efficiently than in plant-based sources. For this reason, individuals eating a plant-based diet may need to consume as much as 50% more of the Recommended Dietary Allowance (RDA) for zinc than omnivores. For the average omnivorous adult male and female, the RDA for zinc stands at 11 mg and 9 mg, respectively. That means that vegan and vegetarian men and women may need up to 16.5 mg and 12 mg per day, respectively. (24) Legumes, whole grains, and other plant-based foods contain a substance known as phytic acid or phytate that can bind to zinc, further inhibiting its absorption. Specific food preparation techniques, such as soaking, boiling, or sprouting, can reduce phytates in foods, thus enhancing zinc bioavailability. (24) Download a handout on anti-nutrients to learn more.

The bottom line

A well-planned vegan diet consisting of fruits, vegetables, whole grains, beans and legumes, and nuts and seeds can have many health benefits; however, certain nutrients are harder to find in plant-based food sources. In some cases, vegans and vegetarians may need to add supplements for vegans to prevent or correct nutrient deficiencies. If you’re a patient, your integrative healthcare practitioner can determine whether you’re at risk for nutrient deficiencies and provide diet and supplement recommendations to help meet your nutritional needs.