Vegan Diets: Nutritional Deficits And How To Avoid Them

Vegan diets are often promoted as being good for heart health, but eliminating animal products may cause nutritional deficiencies and could lead to negative consequences. A comprehensive review published in the medical journal Progress in Cardiovascular Diseases found that a vegan diet may lead to nutritional deficiencies in vitamin B12, omega-3, calcium, zinc, iron, magnesium, and high-quality protein. These deficiencies may be associated with an increased risk for certain types of cancer, stroke, bone fractures, preterm birth, and failure to thrive.

A well-planned vegan diet is rich in fruits and vegetables and generally low in highly refined foods. However, it may not contain all the necessary nutrients, and some nutrients are difficult or impossible to get in adequate amounts from plant foods alone. For example, vitamin B12 is almost exclusively found in animal-sourced foods, and vitamin D3 is found in animal-based foods and is more effective at raising blood levels of vitamin D than the plant form of vitamin D (D2).

Vegan diets are also associated with low intakes of vitamins B2, niacin (B3), iodine, zinc, calcium, potassium, and selenium. Individuals who consume a vegan diet should be aware of the risk of potential dietary deficiencies and may need to take supplements to ensure they are getting all the necessary nutrients.

Vitamin B12

To prevent vitamin B12 deficiency, vegans are advised to consume fortified foods or take supplements. Fortified foods include some plant-based milk alternatives, soy products, and breakfast cereals. It is recommended to consume fortified foods two to three times a day to get at least three micrograms of vitamin B12, or to take a daily supplement providing at least 10 micrograms. Another option is to take a weekly supplement of at least 2000 micrograms.

It is important to note that not all fortified foods contain sufficient amounts of vitamin B12, and the vitamin may not be easily absorbed by the body. Therefore, it is crucial for vegans to regularly monitor their vitamin B12 levels and seek expert advice when transitioning to a vegan diet or when planning a pregnancy.

Overall, while a well-planned vegan diet can be healthy, it is crucial for vegans to ensure they are getting enough vitamin B12 through fortified foods or supplements to avoid potential health issues.

Omega-3

A vegan diet can provide sufficient omega-3 fatty acids, but it requires careful planning. Plant-based sources of omega-3 include walnuts, flaxseeds, chia seeds, hemp seeds, edamame, seaweed, and algae. Other green leafy vegetables and beans also contain small amounts.

The body can convert ALA to EPA and DHA, but the conversion rate is less than 15%. Therefore, it is important for vegans to consume a variety of omega-3 sources to ensure adequate intake. One study found that people who follow vegan diets have intakes above the recommended amounts for omega-3 fats. However, the likelihood of having lower EPA and DHA levels is higher among vegans. To address this, vegans can take supplements derived from microalgae or consume more plant-based sources of ALA, such as ground chia or flax seeds.

In addition to preventing potential deficiencies, omega-3 fatty acids have anti-inflammatory properties that may improve heart and circulatory system health. A well-planned vegan diet that includes a variety of omega-3 sources can provide sufficient omega-3 fatty acids and contribute to overall health.

Calcium

• Dark, leafy greens such as broccoli, cabbage, kale, and collard greens
• Fortified plant-based milk, yoghurt, and orange juice
• Tofu made with calcium sulfate
• Soybeans and soy nuts
• Beans, pulses, and lentils
• Nuts, especially almonds
• Seeds, especially sesame seeds and tahini
• Dried fruit, such as raisins, prunes, figs, and dried apricots
• Bread (in the UK, calcium is added to flour by law)
• Seaweed, such as wakame and kelp

The recommended daily calcium intake for adults aged 19-50 is 1000mg, and 1200mg for women over 51 and men over 70.

Vegans should ensure they eat foods high in calcium and/or take a calcium supplement. Calcium supplements of around 500mg per day are generally considered safe, but it is always best to consult a healthcare professional for advice.

Zinc

Some good sources of zinc for vegans include:

• Pumpkin seeds (2.25mg per 30g)
• Firm tofu (2mg per 100g)
• Raw rolled oats (2.35mg per 100g)
• Baked beans (2.9mg per 1/2 cup)
• Cooked lentils (2.52mg per 1 cup)
• Fortified cereal (1.8mg per 60g)
• Fortified bread (2.4mg per 2 slices)

Additionally, zinc absorption can be improved by using yeast-based and sourdough breads, sprouts, and presoaked legumes. Fermenting soy foods, such as tempeh and miso, also enhances zinc absorption.

While it is possible to get enough zinc from a well-planned vegan diet, some vegans may benefit from taking a modest zinc supplement, especially if they experience symptoms of zinc deficiency, such as frequent colds, angular cheilitis (cracks in the corners of the mouth), diarrhoea, or hair loss.

Iron

Vegans can find non-heme iron in dried beans and legumes, dark green leafy vegetables, dried fruits, nuts and seeds, wholegrain cereals and breads, and other iron-fortified products.

Although vegans can be at risk of iron deficiency, it is a myth that a vegan diet is missing iron. In fact, vegans are no more likely to develop iron-deficiency anaemia than the general population. This is because a vegan diet is typically high in vitamin C, which improves the absorption of non-heme iron.

• Blackstrap molasses
• Lentils (brown, green, and red)
• Tofu and tempeh
• Spinach
• Beans (kidney, soybeans, lima beans)
• Swiss chard
• Whole wheat breads, cereals, pasta, quinoa and oatmeal
• Asparagus and green beans
• Raisins and dried apricots

Pairing high-iron foods with ingredients that are high in vitamin C will enhance your body's ability to absorb iron. Some examples of foods that are rich in vitamin C include:

• Citrus fruits and juices
• Red or green bell peppers
• Kiwi, strawberries, tomatoes, cantaloupe and papaya

On the other hand, some foods can hinder your body's ability to absorb iron. These include:

• Coffee, tea and soda
• Dairy products and calcium supplements
• Foods high in dietary fibre

It is important to note that routine iron supplementation is not recommended for people following a vegan diet, as plenty of iron-rich foods are available. However, if you are concerned about your iron intake, it is best to consult your doctor, who can advise you on whether you need a supplement.

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