Vegan Diets: Nutritional Deficits And How To Address Them

Vegan diets are often promoted as being good for heart health, but eliminating animal products may cause nutritional deficiencies and lead to negative health consequences. A 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 of certain types of cancer, stroke, bone fractures, preterm birth, and failure to thrive. Avoiding animal-sourced food may also be related to higher rates of depression and anxiety. Hair loss, weak bones, muscle wasting, skin rashes, hypothyroidism, and anemia are other issues observed in those strictly following a vegan diet.

Vegan diets are also associated with low intakes of vitamins B2, B3, B12, D, iodine, zinc, calcium, potassium, and selenium. Vitamin B12 is almost exclusively found in animal-sourced foods, and a deficiency can lead to impaired brain function, neurological and psychiatric disorders, and anemia.

Vitamin D is another nutrient that vegans may not get enough of, as it is mostly found in animal-based foods and sunlight. A deficiency in vitamin D is linked to an increased risk of osteoporosis, multiple sclerosis, impaired brain function, and muscle wasting.

Additionally, vegans may not consume enough omega-3 fatty acids, which are important for maintaining heart health and can be found in fatty fish, fish oil, and certain types of microalgae.

To avoid these deficiencies, it is important for vegans to consume a variety of nutritious plant-based foods and consider taking supplements, especially for vitamin B12 and vitamin D.

Vitamin B12 deficiency

Vitamin B12, also known as cobalamin, is an essential nutrient that plays a vital role in the development of red blood cells and the maintenance of nerves and normal brain function. It is almost exclusively found in animal-sourced foods, such as fish, meat, dairy products, and eggs.

Vegans who do not take supplements are at a higher risk of vitamin B12 deficiency than vegetarians. This is because lacto-ovo-vegetarians can get adequate amounts of this nutrient from dairy products and eggs, which are not consumed by vegans.

To prevent vitamin B12 deficiency, vegans should take supplements or eat vitamin B12-fortified foods, such as enriched yeast extracts, nori seaweed, tempeh, and some plant foods and beverages.

Vitamin B12 is a water-soluble nutrient, and humans only need a small amount. However, it is crucial to get this small amount, as vitamin B12 deficiency can have serious health consequences.

Sources of Vitamin B12 for Vegans

Vitamin B12 is not found in significant amounts in plant foods. Vegans can get their vitamin B12 from the following sources:

• Supplements: Taking a daily vitamin B12 supplement that provides at least 10 micrograms is an effective way to ensure adequate intake.
• Fortified foods: Eating fortified foods two or three times a day can provide at least three micrograms of vitamin B12. Examples include fortified plant milk, soy products, and breakfast cereals.
• Natural sources: Nori seaweed is considered the most suitable natural source of vitamin B12 for vegans, although it does not provide a sufficient amount on its own. Other plant foods that contain small amounts of vitamin B12 include tempeh and some types of algae.

Health Risks of Vitamin B12 Deficiency

• Impaired brain function: Vitamin B12 plays a crucial role in maintaining normal brain function. Deficiency can lead to cognitive changes, confusion, depression, memory impairment, psychosis, and fatigue.
• Neurological disorders: Vitamin B12 deficiency can cause neurological complications such as loss of sensation, postural hypotension, muscle weakness, and loss of mental and physical drive.
• Psychiatric disorders: Low vitamin B12 levels have been linked to an increased risk of psychiatric disorders.
• Anaemia: Megaloblastic anaemia is a common consequence of vitamin B12 deficiency.
• Alzheimer's disease: There is a possible link between vitamin B12 deficiency and an increased risk of Alzheimer's disease.
• Heart disease: Vitamin B12 deficiency may be associated with an increased risk of heart disease.

Monitoring Vitamin B12 Levels

It is important for vegans to regularly monitor their vitamin B12 levels to prevent deficiency. Checking blood vitamin B12 levels is one way to assess vitamin B12 status. However, blood tests may not always be reliable, especially in vegans who consume algae or other plant foods that contain B12 analogues, which can interfere with vitamin B12 metabolism.

More specific tests for vitamin B12 status include measuring methylmalonic acid (MMA) and homocysteine levels. MMA is considered a more reliable marker of vitamin B12 status than serum vitamin B12 levels.

In summary, vitamin B12 deficiency is a serious health risk for vegans who do not ensure adequate intake through supplements or fortified foods. It is important to be proactive in preventing vitamin B12 deficiency by including reliable sources of this nutrient in the diet and regularly monitoring vitamin B12 levels.

Vitamin D3 deficiency

Vitamin D3, also known as cholecalciferol, is a type of vitamin D that is found in animal-sourced foods, especially fatty fish. It is more effective at raising blood levels of absorbable vitamin D than the plant form of vitamin D (D2).

Vitamin D plays an important role in maintaining healthy bones by helping to control the amount of calcium and phosphate in our bodies. It also supports the normal functioning of the immune system.

Vitamin D can be created by exposing the skin to sunshine, but this can be difficult for those who live far from the equator or who have limited sun exposure. For this reason, it is often necessary to obtain vitamin D from food or supplements.

The best sources of vitamin D3 are fatty fish and egg yolks. Other sources include supplements, cod liver oil, or enriched foods like milk or cereals.

Vegans may be at a higher risk of vitamin D3 deficiency, especially during the winter in countries north or south of the equator, as the main dietary sources of vitamin D3 are not plant-based.

Deficiency in vitamin D is linked to an increased risk of various adverse health conditions, including osteoporosis, multiple sclerosis, impaired brain function, and muscle wasting.

To ensure adequate vitamin D3 intake, vegans can consume vitamin D3 supplements made from lichen. Exposing the skin to sunlight can also help increase the body's natural vitamin D production.

DHA (omega-3 fatty acids) deficiency

DHA, or docosahexaenoic acid, is an essential omega-3 fatty acid that plays a crucial role in normal brain development and function. A deficiency in DHA can have adverse effects on mental health and brain function, especially in children. Additionally, inadequate DHA intake in pregnant women may negatively impact fetal brain development.

DHA is predominantly found in fatty fish, fish oil, and certain types of microalgae. While the body can convert the omega-3 fatty acid ALA, found in high amounts in flaxseeds, chia seeds, and walnuts, into DHA, the conversion process is inefficient and may not sufficiently increase DHA levels in the blood. As a result, vegetarians and vegans often have lower DHA levels than meat-eaters.

To ensure adequate DHA intake, vegans can include ground chia or flax seeds in their daily diet. These seeds are rich in ALA and can meet daily requirements with just one tablespoon. Additionally, taking a vegan DHA/EPA supplement derived from microalgae can help ensure sufficient DHA levels.

While the benefits of DHA are well-established, the optimal DHA dose from supplements is still under investigation. However, given the potential benefits of DHA for brain function and the possible risks associated with DHA deficiency, it is advisable to take a few hundred milligrams of a DHA/EPA supplement daily, especially for those with increased needs, such as pregnant and lactating women, the elderly, or individuals with certain chronic diseases.

Calcium deficiency

Calcium is the most abundant mineral in the human body and is essential for keeping our bones and teeth healthy and strong. It also plays a role in maintaining a healthy immune system, effective blood clotting, and helping our muscles contract and relax.

Vegans may be at risk of developing calcium deficiency because they don't consume dairy, which is often thought of as the only source of this mineral. However, there are plenty of vegan calcium-rich foods and drinks that can help maintain healthy levels of calcium. These include:

• Soybeans and foods made from soybeans, such as tofu, tempeh, and natto
• Beans, peas, and lentils
• Nuts, especially almonds and Brazil nuts
• Seeds and their butters, such as tahini
• Grains, such as amaranth and teff
• Certain vegetables and leafy greens, such as spinach, turnip greens, mustard greens, and collard greens
• Fortified foods and drinks, such as plant yogurts, cereals, flour, cornmeal, and plant milks
• Blackstrap molasses

While it is possible for vegans to get enough calcium through diet alone, it is important to be mindful of symptoms of calcium deficiency, which include muscle aches and cramps, numbness and tingling in the hands and feet, dry or brittle nails, and severe premenstrual syndrome (PMS) symptoms. Long-term calcium deficiency can lead to osteoporosis, severe dental problems, depression, chronic joint and muscle pain, and bone fractures.

Protein deficiency

Protein is an essential nutrient involved in virtually all cell functions. In the body, protein is required for structural support, and the maintenance and repair of tissues. It is also the basic component for immunity, most hormones, and all enzymes, among other functions.

The most severe form of protein deficiency is known as kwashiorkor, which most often occurs in children in developing countries where malnutrition and imbalanced diets are more common. However, protein deficiency is not limited to developing countries, and can occur in vegan diets if not properly planned.

Edema

Edema is a condition characterised by swollen and puffy skin. It is a classic symptom of kwashiorkor and may be caused by low amounts of human serum albumin, which is the most abundant protein in the liquid part of the blood, or blood plasma. One of albumin’s main functions is to maintain oncotic pressure – a force that draws fluid into the blood circulation. In this way, albumin prevents excessive amounts of fluid from accumulating in tissues or other body compartments. Because of reduced human serum albumin levels, severe protein deficiency leads to lower oncotic pressure, resulting in fluid accumulation in tissues and causing swelling.

Fatty liver

Fatty liver, or fat accumulation in liver cells, is another symptom of kwashiorkor. Protein deficiency has been associated with fatty liver disease in developing countries. This condition may cause inflammation, liver scarring, and potentially liver failure. It is unclear why fatty liver disease occurs with protein deficiency, but research suggests it may be due to changes in the gut microbiome, mitochondria, and peroxisomal cells. This may lead to impaired synthesis of fat-transporting proteins, known as lipoproteins.

Skin, hair, and nail problems

Loss of muscle mass

When dietary protein is in short supply, the body tends to take protein from skeletal muscles to preserve more important tissues and body functions. As a result, a lack of protein could lead to muscle wasting over time, especially in older adults. Research suggests that adults aged 65 and older should consume at least 0.5 grams of protein per pound of body weight, which is more than the recommended daily allowance of 0.36 grams. Increased protein intake may help prevent sarcopenia, which is the slow loss of muscle associated with ageing.

Greater risk of bone fractures

Not eating enough protein may weaken your bones and increase the risk of fractures. A 2021 study found that participants who ate higher amounts of protein had up to 6% higher bone mineral density in their hips and spine than those who ate less protein. After five years, the researchers found that those who ate more protein were less likely to experience bone fractures.

Stunted growth in children

Insufficient protein intake may delay or prevent growth in children. In 2020, over 149 million children had stunted growth. Children who don’t regularly consume enough protein may be four times more likely to have stunted growth.

Increased severity of infections

A protein deficit may take a toll on your immune system. For instance, eating enough protein is important to help build antibodies, which are produced by your white blood cells to help fight infections. A 2013 study in male athletes who engaged in high-intensity exercise found that participants who consumed a high-protein diet experienced fewer upper respiratory tract infections than athletes consuming a low-protein diet.

Greater appetite and calorie intake

Protein plays a key role in appetite maintenance and total calorie intake. If you’re not consuming enough protein, your body attempts to restore your protein status by increasing your appetite and encouraging you to find something to eat. This may lead to consuming foods high in carbs and fat to compensate for the lack of protein, which is known as the protein leverage hypothesis. However, foods high in carbs and fats are not as satiating as high-protein foods. Over time, this may lead to eating too many calories, causing unintended weight gain and obesity.

Preventing protein deficiency

The amount of protein you need to consume per day may depend on several factors, such as your age, level of physical activity, and fitness goals. Dietary Guidelines for Americans 2020 to 2025 recommends adult females consume 46 grams and adult males 52 to 56 grams of protein daily. On average, this equates to 0.36 grams per pound (0.8 grams per kilogram) of body weight. However, research suggests this is the minimum requirement to prevent muscle loss and chronic conditions. If you’re trying to gain muscle mass, the International Society of Sports Nutrition recommends eating 0.6 to 0.9 grams per pound (1.4 to 2 grams per kilogram) of body weight. The authors note that people who resistance train may also benefit from eating up to 1.3 grams per pound (3 grams per kilogram) of body weight.

If you think you have protein deficiency, speak with a healthcare professional or registered dietitian. They could help develop a nutrition plan that’s right for you.

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