Increasing numbers of people are turning to veganism – a diet free from all animal-derived products. Ethical and environmental factors aside, what does this mean for health?

There aren’t many long-term studies on the effects of a vegan diet but what is clear is that a poorly planned vegan diet is likely to be lacking certain essential nutrients required by the body. It therefore takes careful consideration to ensure that you’re not missing out on anything that’s going to impact your overall health. The most common deficiencies in a vegan diet are protein (I’ve written a separate post about plant-based protein), vitamin B12, Omega 3, Iron and vitamin D.

Vitamin B12

This is a vitamin predominantly found in animals and therefore almost impossible for someone who is vegan to obtain through diet alone. It is essential for brain function and red blood cell production and deficiency can impact neurological health and has been linked to anaemia.1 Foods fortified with vitamin B12 are a viable option – for instance many plant-milks, but the quantity of B12 will vary. It may be advisable to consider a B12 supplement, but please only do so having spoken to a professional (see my post on why you should seek advice before starting a supplement program).

Omega 3

Research has shown that omega 3 fatty acids are important for heart health, reducing inflammation, healthy bones and joints, skin health, blood sugar balance and have even been linked to mental health (though further research is needed).2, 3, 4 There are 3 key types of omega 3 fatty acids, alpha-linolenic acid (ALA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). ALA cannot be produced endogenously (in the body) so must be obtained from the diet – it then helps the body to produce EPA and DHA. Vegan sources of ALA include chia, hemp and flax seeds. It is also possible to get EPA and DHA through an algae-based supplement – a professional can advise you on this.


Iron vital for numerous metabolic processes, the health of your red blood cells, and delivering oxygen to every cell in the body.5 There are two forms of iron: heam iron (from animals) and non-haem iron (from plants). Non-haem iron is less ready absorbed and utilized by the body than haem iron, but absorption can be increased by including foods rich in vitamin c. The good news is that the plant world is so clever that many vegetables high in iron also contain vitamin C – like dark leafy green vegetables. You could also try serving your greens with a squeeze of lemon juice to boost the vitamin C. Lentils, kidney beans and pumpkin seeds have high levels of iron. It is never advisable to supplement with iron unless you have had your iron levels measured – this is because iron can become toxic in high volumes.

Vitamin D

Vitamin D has many roles in the body, including helping calcium be absorbed into the bones, facilitating gene expression6,
regulating blood pressure7 and supporting the immune system – with a possible role in autoimmune conditions too.8 In the UK, most of us are not getting sufficient vitamin D intake from sun exposure alone and must therefore look to our diets, but the main dietary sources are meat, fish and eggs. It is now widely recommended that we supplement vitamin D through the winter, but another easy way to get some more into a vegan diet is through fortified foods such as many widely available plant milks.

These are just the basics but if you are vegan, or are considering following a vegan diet, I strongly recommend either asking for help from a qualified professional (come see me!) or taking some time to research what you will need to include on a regular basis.


1. Rizzo, G., Laganà, A., Rapisarda, A., La Ferrera, G., Buscema, M., Rossetti, P., Nigro, A., Muscia, V., Valenti, G., Sapia, F., Sarpietro, G., Zigarelli, M. and Vitale, S. (2016). Vitamin B12 among Vegetarians: Status, Assessment and Supplementation. Nutrients, 8(12), p.767.
2. Bozzatello, P., Brignolo, E., De Grandi, E. and Bellino, S. (2016). Supplementation with Omega-3 Fatty Acids in Psychiatric Disorders: A Review of Literature Data. Journal of Clinical Medicine, 5(8), p.67.
3. Swanson, D., Block, R. and Mousa, S. (2012). Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Advances in Nutrition, 3(1), pp.1-7.
4. Gammone, M., Riccioni, G., Parrinello, G. and D’Orazio, N. (2018). Omega-3 Polyunsaturated Fatty Acids: Benefits and Endpoints in Sport. Nutrients, 11(1), p.46.
5. Abbaspour, N., Hurrell, R., & Kelishadi, R. (2014). Review on iron and its importance for human health. Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences, 19(2), 164–174.
6. Heaney, R. (2008). Vitamin D in Health and Disease. Clinical Journal of the American Society of Nephrology, 3(5), pp.1535-1541.
7. Jeong, H., Park, K., Lee, M., Yang, D., Kim, S. and Lee, S. (2017). Vitamin D and Hypertension. Electrolytes & Blood Pressure, 15(1), p.1.
8. Aranow, C. (2011). Vitamin D and the Immune System. Journal of Investigative Medicine, 59(6), pp.881-886.