Common deficiencies with a Vegan diet

Deciding whether or not to follow the trend towards vegan diets? Are they healthier than omnivorous diets? While touching on nutrient deficiencies that occur in common diets, I decided to delve a bit further into the topic. It is important to understand that I am not against vegan or vegetarian diets, but for health reasons, I do believe that good quality animal foods are beneficial for my body.

If you are following a vegan diet, you are most probably sticking away from all animal products, including vitamin and supplement forms. It is important to take note of the below common nutrient deficiencies, and either focus on plant-based sources, or supplementation options. Taking on this lifestyle requires some work to make sure that your body is working optimally. Let’s start with the most common deficiency, and the most well-known – Vitamin B12.

Vitamin B12

Vitamin B12 is an essential vitamin that is only found in animal food sources, such as meat, fish, dairy products and eggs.

Role of vitamin B12 in the body: Energy production, blood formation, DNA synthesis, reproductive health and digestion. All you need to really know – we need this vitamin for energy and digestion (1). Vitamin B12 plays an important role in stomach acid regulation, and the two are co-dependant. Stomach acid helps to digest food in the stomach, before transferring it to the intestines. Without it, digestion may be impaired. Another impact of low vitamin B12 is elevated homocysteine levels, which is associated with higher risk of heart disease and stroke. Vegans who supplement with vitamin B12 have shown homocysteine levels within the normal range. (5)

Signs of deficiency: Weakness and fatigue, impaired brain function and anaemia. (1)

So now what?  There are 2 options. You can include foods that have been fortified with vitamin B12. Other plant-based sources of vitamin B12 are Nori seaweed and tempeh (fermented soy). (1) If you do not eat these foods regularly, it may be a good idea to speak to your pharmacist about the best vitamin B12 supplement.

Omega 3 Fatty Acids

These are known as essential fatty acids as they cannot be made by the body, and are only obtained through the diet. There is a special omega pathway in the body, which explains how the omega fatty acids are converted from food into their usable state.

For now, we will only be focusing on the omega 3 pathway. In this pathway, alpha linoleic acid (ALA) is obtained through plant-based sources. This requires vitamin B6, magnesium, zinc, vitamin C and niacin in order to be converted to its active form in the body (DHA). One can see where the problem lies here – a deficiency in any of the contributing nutrients, may lead to an inefficiency in this pathway. Marine animals, such as krill and oily fish are able to supple omega 3 in its active form, also known as DHA (1)

Role of Omega 3 fatty acids in the body: Normal brain function and cognitive health, heart health, normal development (in children) and natural anti-inflammatory. (1) Its role in regulating inflammation is especially important as inflammation is a major factor in conditions such as asthma, depression, cardiovascular disease, ADHD and rheumatoid arthritis.

Signs of efficiency: Fatigue, dry skin, poor concentration, poor circulation and mood swings. (8)

So now what? DHA can be made from ALA, which is found in flaxseeds, chia seeds and walnuts. (1) However, it is important to have adequate levels of the contributing nutrients, in order to convert ALA to DHA. Plant-based sources of omega 3s are especially valued when paired with an animal source such as krill oil. (1) There are also a number of omega 3 supplements in the market – Krill oil is a known favourite!


Iron is found in both animal and plant sources, however, the type of iron differs. (1) Heme-iron is only found in meat, and mainly red meat. It can also be found in chicken and fish, and is more easily utilised by the body than non-heme iron. (2) Plant sources of iron are primarily non-heme, and is poorly absorbed by the body. (1) To add to this, heme-iron helps with the absorption non-heme iron. (1) In this case it is beneficial to combine plant and animal sources of iron.

Role of iron in the body:  Iron carries oxygen to the tissues in the body. Without proper oxygenation, cells start to die. This can lead to anaemia.

Signs of deficiency: Fatigue and weakness

So now what? If you are going the vegan route, it is important to include vegan sources of iron in the body. Try soy milk, tofu, beans, lentils, quinoa and green leafy vegetables like spinach. Remember that this is non-heme iron and may be poorly utilised by the body. Vitamin C is a factor that can enhance absorption of non-heme iron, so try including fresh fruits and vegetables that are high in vitamin C. (2)


I find the whole ‘Calcium comes from dairy’ story a bit tiring. There are a numerous amount of non-dairy calcium sources. Meeting your adequate calcium requirement on a vegan diet does not require too much work. True – it is easy to be deficient of calcium on a vegan diet, but this does not need to be the case.

Role of calcium in the body: Important component for bone health, as well as teeth, nails and hair health.

Signs of deficiency: Brittle nails, rough hair, muscle cramps, premenstrual cramps, and insomnia or poor sleep quality (9)

So now what? Include green leafy vegetables such as spinach, broccoli, turnips and kale for plant-based sources of calcium. Orange juice and all kinds of beans are also valued sources of non-dairy calcium. (2)


Sulfur is an interesting one, and often forgotten when looking into common deficiencies of vegan diets. Sulfur is derived primarily from animal sources such as fish and high quality beef and chicken. When following a vegan diet, it is common to be at risk of a sulfur deficiency. Vegans who eat a grain-heavy diet, with a high intake of processed foods are at greater risk. This is because sulfur is lost during processing. (1) Low sulfur has been associated with high homocysteine levels, which has been associated with higher risk of cardiovascular disease.

Role of sulfur in the body: Sulphur plays an important role in detoxification, glutathione synthesis and proper insulin function. It supports the conversion of vitamin B1 and biotin, which are both essential for converting carbohydrates to energy. (1) A deficiency can affect bones, joints, connective tissue and metabolic processes. (1)

Symptoms of deficiency: Acne, arthritis, brittle hair and nails, rashes, slow wound healing, depression, chronic fatigue, weight gain and poor memory. (10)

So now what? If you are following a vegan diet, it is important to include a wide variety of sulfur-containing foods such as coconut oil, olive oil, wheat germ, legumes, garlic, onion, Brussels sprouts, asparagus and kale. It may be beneficial to supplement with MSM, and organic form of sulfur naturally found in many plants. (1)  Sun exposure has also shown beneficial in boosting sulfur levels. (10)


It’s not actually difficult to meet protein requirements on a vegan diet – you just need to be sensible about it.

Role of protein in the body: Protein is required for muscle maintenance, bone health, immune strength and to prevent fatigue. (6) Luckily for vegans, the liver stores various essential amino acids, so it is not crucial to combine different protein sources at each meal. Eating an assortment of plant-based protein over the course of the day can provide all the amino acids, and ensure protein requirements are met. Lysine is the most important amino acid to focus on here. Activity increases calorie requirements, making it easier to meet lysine requirements. (6) Creatine is an amino acid found in animal foods that is important for muscle energy and brain health. It might be an idea to supplement with Creatine, especially if taking part in a lot of exercise. (1) Because protein from plant-based sources are more difficult to digest than animal proteins, it may be beneficial for vegans and vegetarians to increase their protein intake by approximately 10%. For the average athlete, this is 1.3 – 1.8 g/kg/day. (6)

Signs of deficiency: Sugar cravings, brittle hair and hair loss, fatigue, brain fog and low immune health.

So now what? Lysine can be obtained from legumes, amaranth, quinoa, pistachios, pumpkin seeds and soybeans. Legumes include soybeans, kidney beans, pinto beans, hummus, green peas, split peas, black-eyed peas, lentils and peanuts. (6) Protein can also been found in a mixture of raw nuts. (3) By mixing grains and beans in a meal, methionine and lysine requirements are more easily met. (6)

I am not saying that it is unhealthy to choose a specific diet, but it is important to take these common deficiencies into mind, and supplement accordingly. Each and every person is different, and specific diets are suited to specific people. It is all about listening to what our body wants, and eating for optimal nutrition. Personally, my body works best when I include small amounts of high quality animal products. I eat a wide variety of seafood, meats, poultry and dairy products. Being vegan is not the ‘healthier’ choice, it is just another choice. Be mindful, listen to your body, and if you feel best on a vegan diet, be sure to keep these common deficiencies in mind.


Reference list



Each and every person is different, and specific diets are suited to specific people. It is all about listening to what our body wants, and eating for optimal nutrition.
Vitamin C is a factor that can enhance absorption of non-heme iron, so try including fresh fruits and vegetables that are high in vitamin C.
fruit &veg basket
Include green leafy vegetables such as spinach, broccoli, and kale for plant-based sources of calcium.
spinach leaves