Potential Nutrient Deficiencies in a Vegan Diet

First things first, what is a Vegan Diet?

A vegan diet is absent from all types of animal products such as meat, eggs and dairy, and consists entirely of plant-based foods including fruits, vegetables, grains, nuts and seeds. This diet is incredibly rich in fibre, antioxidants, vitamins and minerals, whilst being naturally low in salt and saturated fats. There is also a positive association between a vegan diet and a reduced risk of obesity, reduced likelihood of cardiovascular disease and type 2 diabetes, and even a reduction in cancer risk. The evidence is clear that reducing animal-based sources can help optimise nutrition, with plenty of beneficial outcomes, however, if you decide to steer towards a vegan diet, considerations need to be made regarding nutrients mainly found in animal sources. Below are the 5 main nutrients that people as vegans need to be mindful of, and how to combat potential deficiencies.

Vitamin B-12

A water-soluble vitamin found in large quantities in animal products, B-12 is important for proper central nervous system functioning and the synthesis of DNA. Recommended daily intake for B-12 is 2.4 micrograms. Symptoms of deficiency can include fatigue, weakness and loss of appetite, though long term could result in the development of anaemia or neurological damage. Deficiency is much slower in those who previously ate meat, as B-12 can be stored in the liver for several years, however, it can only be completely halted by adequate intake of fortified products such as cereals, plant milks and nutritional yeast, which can provide anywhere between 25% -100% of the daily intake requirements.


Iron is essential for red blood cell production and oxygen transport. It’s found in two forms, heme and non-heme and is found in animal products and plant-based sources respectively. Men need around 8mg per day and women 18mg[DD|HY1] . A higher intake of iron is required for women due to iron losses in the blood during the menstrual cycle, and additionally, those who are pregnant require a further 10mg/day due to an increase in blood volume. Lack of iron in the diet can lead to iron induced anaemia, which can cause muscle weakness, impaired body temperature regulation and disrupted cognitive functioning. Availability of iron from plant-based sources is much lower than in meat meaning our body requires more overall non-heme iron, however by consuming adequate amounts of iron sources, this will not be an issue. Vitamin C can enhance the availability of iron in these circumstances too, so it might be worth having some orange juice as you eat your meal. Be sure to consume a variety of whole grains, nuts, beans, dark leafy greens and fortified cereals to help increase your iron intake.


Iodine is an essential mineral required to produce thyroid hormones and can be found naturally within the ocean environment and iodine rich soils. Daily requirements sit at around 150 micrograms per day, and deficient intake can result in hypothyroidism, which negatively affects metabolism[DD|HY2] . Iodine status is particularly important during pregnancy, as deficiency can directly cause both maternal and foetal hypothyroidism, and additionally, foetal brain development can be hindered. Seaweed and fish such as cod and oysters are the top sources of iodine due to their presence within the ocean, as well as iodized salt which can be added to home cooked meals. It is worth checking the labels on plant-based milks and fortified cereals/ breads for ‘potassium iodate’ to help increase iodine intake[DD|HY3] . The best way to increase iodine intake is by oral supplementation containing the appropriate dosage of 150 mcg, especially if your diet does not consist of seaweed or fortified foods.

Omega-3 Fatty Acids

These long chain fats typically found in marine sources have an array of health benefits and are linked to healthy aging through life. EPA and DHA are the 2 main classes of omega-3 fatty acids, which can be found abundantly in fish. These types of fatty acids help reduce inflammation and support cardiovascular functioning. A third type of omega-3, ALA, is only found in plants, however, can be converted to either EPA/DHA to help provide the same health benefits. Despite the ability to convert ALA to a more active form, studies show only 2-10% of the ALA consumption can be converted, which poses risk of deficiency within vegan populations. It is still advisable to increase intake of ALA from foods such as flaxseed (ground or oil), hempseed, walnuts, and canola oil. Limiting intake of omega-6 by swapping margarines, sunflower, safflower, and corn oils for monounsaturated fats such as olive oil, canola oil and nuts is also advised, as these are also associated with reduced [bad] cholesterol levels Consuming an EPA/DHA supplement composed of microalgae, at a dose of 200-300mg/day would also be beneficial to populations where fish intake is minimal or avoided.

EPA = Eicosapentaenoic acid. DHA = Docosahexaenoic Acid. ALA = Alpha-Linolenic Acid


Calcium is a mineral that is used by the body for several functions and is associated primarily with good bone health. Additionally, calcium has been shown to lower blood pressure and cholesterol levels. Deficiency of calcium can lead to the development of osteoporosis, in which bones weaken and become increasingly susceptible to fractures. Calcium absorption is heavily dependent on vitamin D status, so ensuring adequate UV exposure or taking a vitamin D supplement during the winter months is essential. Although found in abundance in dairy products such as cheese and milk, calcium can be found in plant-based sources including broccoli, kale and watercress. Even higher amounts can be found in nuts and seeds including almonds, chia seeds and sesame seeds, though it is worth being mindful of the associated calorie content when consuming these in large quantities. Fortified products such as soy and almond milk, and some cereals are a great source of calcium and can help offset the lower calcium intake associated with those who do not consume dairy, just be sure to check the labelling to ensure the product is supplemented[DD|HY4] .


Proper planning of a vegan diet is essential to making sure a full range of essential nutrients are obtained. Fortified foods such as cereals and plant-based milk products play a large role in providing nutrients that are less commonly found naturally in plant foods. Additionally, consuming large amounts of vegetables, fruits, nuts, seeds, and monounsaturated oils is essential to providing the body with vital nutrients. Raising awareness of the potential deficiencies that can occur is crucial to maintaining proper bodily functioning long term, and hopefully this by reading this article, you can implement some of these recommendations into your own diet to ensure sufficient nutrient intake.


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  5. Burns-Whitmore B, Froyen E, Heskey C, Parker T, San Pablo G. Alpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet: Do They Require Dietary Reference Intake/Adequate Intake Special Consideration?. Nutrients. 2019;11(10):2365. Published 2019 Oct 4. doi:10.3390/nu11102365, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6835948/

Vegan Eatwell Guide   

Eugene Gristock 

Potential Nutrient Deficiencies in a Vegan Diet      
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