Vegan Diets: Avoiding Vitamin Deficiency

Vegan diets have gained popularity over the last decade, but they may not contain all the necessary nutrients. Vegans can be at risk of vitamin B12, omega-3, calcium, zinc, iron, magnesium, and high-quality protein deficiencies. These deficiencies can lead to health issues such as hair loss, weak bones, muscle wasting, skin rashes, hypothyroidism, and anemia. However, consuming fortified foods and supplements can help ensure vegans get sufficient nutrition.

Vitamin B12 deficiency

Vitamin B12, also known as cobalamin, is a critical nutrient that plays a vital role in forming red blood cells and DNA synthesis, supporting the function and development of brain and nerve cells, and maintaining optimum energy levels. It is an essential vitamin for the cells, and a deficiency can lead to serious health consequences, such as pernicious anaemia.

Vitamin B12 is naturally found in animal products such as meat, fish, eggs, and dairy. Vegans, therefore, need to be mindful of their intake and seek fortified food sources as well as take supplements as needed.

It is currently unknown how long it takes for vitamin B12 deficiency to occur in individuals adopting a vegan diet. The symptoms may be subtle and often ascribed to stress or other lifestyle events. Even as more symptoms manifest, they may be misinterpreted, because vitamin B12 deficiency can occur without serum levels being below the usual diagnostic cut-off for 'deficiency' or without an associated diagnosis of megaloblastic anaemia.

• Cognitive changes (such as depression, memory impairment, confusion, psychosis, and tiredness)
• Dyspnoea
• Loss of sensation
• Postural hypotension
• Muscle weakness
• Loss of mental and physical drive
• Anaemia
• Nerve damage
• Neurological disorders
• Reduced growth and healing
• Weakness and fatigue
• Tingling in the hands and feet
• Problems with the digestive system
• A sore tongue or mouth ulcers
• Feeling faint or dizzy
• A decline in memory, judgement, and understanding
• Tinnitus (ringing, buzzing, or hissing sounds in the ears)

Recommendations for supplementation vary from source to source, and a lot depends on the vitamin B12 level you have when you get tested. One daily B12 supplement of at least 50 micrograms is often recommended. In general, vegans seem to get enough vitamin B12 to avoid very severe health problems like anaemia and nervous system damage. However, many individuals who follow a plant-based diet fail to consume adequate B12 to eliminate potential risks surrounding heart disease or pregnancy complications in women.

How to Ensure You're Getting Enough Vitamin B12 on a Vegan Diet

• Include foods that are fortified with B12 in your diet. This includes things like B12-fortified breakfast cereals, non-dairy milk, and nutritional yeast.
• Take a daily supplement that contains B12.
• Get your B12 levels tested regularly.

Population Groups at Higher Risk of Vitamin B12 Deficiency

• Women of child-bearing age
• Pregnant and lactating women
• Older adults
• Individuals who are already following a plant-based diet (vegetarians) and who transition to a vegan diet

Iron deficiency

Iron is an essential nutrient, as it is a central part of haemoglobin, which carries oxygen in the blood. Iron is also used to make myoglobin, which stores oxygen in our muscle cells. Iron is also part of many important enzymes, which are substances that speed up chemical reactions.

There are two types of iron: heme and non-heme. Heme iron is found in animal products and is generally easier for the body to absorb. Non-heme iron is found in vegan foods and is not as easily absorbed. Vegans should be aware of foods that are high in iron and techniques that can promote iron absorption.

Iron can be obtained from a well-planned vegan diet as there are lots of plant foods containing reliable sources of non-haem iron, such as legumes (beans, peas, and lentils) and dark leafy green vegetables (e.g. spinach and collards). It is recommended to include foods high in vitamin C with meals, as this increases iron absorption. For example, oatmeal with orange juice provides iron from the oats and vitamin C from the juice.

Tea, coffee, and calcium supplements should be consumed several hours before a meal that is high in iron, as they can reduce iron absorption.

Calcium deficiency

Calcium is the most abundant mineral in the human body, with about 40% of the mineral mass of our bones made up of calcium. It is needed to keep our bones and teeth healthy and strong, and is also required for a healthy immune system, effective blood clotting, and helping our muscles contract and relax.

Some research has shown that vegans have a lower intake of calcium compared to non-vegans, and as a result, many studies have shown vegans to have a lower bone mineral density and a higher risk of fractures. Calcium deficiency can have negative implications for bone mass, especially during periods of growth. If dietary calcium intake is inadequate at this time, it can cause poor bone health later in life.

The recommended daily intake of calcium for adults aged 19 to 50 is 1,000 mg, and for women aged 51-70, the recommended daily intake raises to 1,200 mg. All adults over the age of 70 are recommended to intake 1,200 mg of calcium.

There are plenty of vegan sources of calcium, including fortified soya, rice, and oat drinks; bread (in the UK, calcium is added to white and brown flour by law); dried fruit; calcium-set tofu; and calcium-fortified foods. There are also many calcium-rich fruits and vegetables, such as oranges, apricots, strawberries, collard greens, turnip greens, mustard greens, broccoli, sweet potatoes, and butternut squash.

Omega-3 deficiency

Omega-3 fatty acids are important for maintaining heart and brain health, kidney function, eye health, and skin health. They are considered essential fatty acids, and play an important role in cellular function.

The body's primary source of omega-3 is alpha-linolenic acid (ALA), which it converts into docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). While ALA is readily available in plant-based foods, DHA and EPA are found in fish and other animal products.

Vegan diets are often associated with low omega-3 levels, particularly DHA and EPA. However, the body can convert ALA into DHA and EPA, albeit slowly and inefficiently. This conversion process is influenced by genetics, sex, age, and dietary composition.

A study found that while the levels of ALA-derived omega-3s were similar in vegans and non-vegans, the levels of DHA and EPA were lower in vegans. Another study found that vegans had significantly more long-chain omega-3 fats in their blood compared to fish eaters, meat eaters, and ovo-lacto-vegetarians.

To optimise their omega-3 levels, vegans can focus on consuming plant-based sources of ALA, such as walnuts, flaxseed, chia seeds, hemp seeds, edamame, seaweed, and algae. Additionally, reducing the intake of linoleic acid may help improve the conversion of ALA to DHA and EPA.

For those with increased needs or reduced conversion ability, such as pregnant and lactating women, the elderly, or individuals with chronic diseases, supplementation with DHA and EPA derived from microalgae may be beneficial.

While most people following plant-based diets can get sufficient omega-3s, vegans should be mindful of their intake and consider supplementation if necessary.

Vitamin D deficiency

Vitamin D is an essential vitamin that most people, including vegans, don't get enough of. It is technically a hormone and is needed to keep bones healthy by aiding in calcium absorption. When vitamin D is in short supply, bones become brittle and rickets can occur. It also plays a role in cell growth, immune function, and mediating inflammation in the body.

Vitamin D is unique compared to other vitamins because your body can make it through exposure to sunlight. However, this may not be a reliable source, and vitamin D deficiency is very common. In fact, 41.6% of Americans may be deficient in vitamin D.

Vegans are at an increased risk of vitamin D deficiency because most food sources of vitamin D are animal-based. The only vegan food that naturally contains a decent amount of vitamin D is mushrooms, specifically those exposed to ultraviolet light. Other vegan options include fortified foods and beverages, such as plant-based milks, cereals, and orange juice.

To ensure adequate vitamin D intake, it is recommended that vegans consume vitamin D-fortified foods, spend time in the sun, and consider taking a vegan vitamin D supplement. Spending 10 to 30 minutes in the sun a few times a week is usually sufficient, but those with darker skin may need more sun exposure.

If you are concerned about vitamin D deficiency, it is recommended to consult a healthcare professional, who can advise on the best course of action and perform a blood test to check vitamin D levels.

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