Vegan and Vegetarian: What Nutrients Could You Be Lacking?

Veganism and vegetarianism is on the rise in the Western world, with many claiming a host of health benefits from switching to one of the diets. Between 2014 and 2019, the number of vegans in the UK quadrupled. As of January 2021, approximately 79 million people in the world were vegan. While 3.3 million people in Britain are vegetarian and a staggering 1.5 billion people worldwide are estimated to be vegetarian.

Although there are many benefits to going vegan or vegetarian, many believe it’s hard to get the right vitamins on one of the diets. So here we look at some of the most common nutritional deficiencies faced when on one of the diets. Firstly, we want to point out that many people follow a vegetarian or vegan diet without issue, and these are just a list of deficiencies some suffer from.


When it comes to iron, plants contain non-heme iron. The trouble with non-heme iron is the body does not as easily absorb it. Heme iron is mainly found in red meat, which is, of course, out of the question. For this reason, some vegans and vegetarians find they can be deficient in iron; this is particularly common in women. Be cautious, though. An excess of iron also can be a bad thing.

Vitamin B12

Probably the most common deficiency for those on a plant-based diet. Vitamin B12 is found in meat, fish, dairy products and eggs. For those that are vegetarian, this does allow some possibilities. People on a vegan diet may struggle, however B12 is in seaweed, tempeh (fermented soy), nutritional yeast flakes and spirulina. Nevertheless, it can be challenging to consume the adequate quantity needed.

Vitamin D3

A common vitamin lacking in many people; in fact, roughly 1 in 5 of us have low levels of D3. While this isn’t exclusive to plant-based diets, those who consume meat, fatty fish and eggs can get an extra boost. The best source of D3 is sunlight, but this can be particularly difficult in the darker, cloudier months.


Omega-3, specifically DHA (docosahexaenoic acid) omega-3, is vital for health. Most of our brain is made up of DHA omega-3s. Omega3 is primarily found in oily fish such as salmon, trout, mackerel etc in its active form (EPA/DHA), obviously this is only relevant for pescatarians and others that don’t follow a vegan or vegetarian diet. However, omega-3 is also in flaxseeds, flax oil, hemp seeds, chia seeds and walnuts in the form of ALA (which then needs to be converted to EPA/DHA). However, it isn’t easy to gain enough from these sources. Also, it is worth pointing out that vegan and vegetarian supplements will be in ALA (alpha-linolenic acid) form instead of DHA, meaning the body will have to convert them first.


Finally, iodine is notoriously difficult to obtain from plant foods. It is, however in some fortified cereals and seaweed. However, it’s difficult to know what quantity you will get as it can vary considerably. Some plant milks are now available with iodine (keep an eye out for potassium iodine on the ingredients). Still, one of the easiest ways to hit your recommended intake is with a supplement.


While it may sound like vegan and vegetarian diets can cause deficiencies, we want to mention that there is nothing wrong with following a vegan or vegetarian diet. On the contrary, many who follow a plant-based lifestyle are healthier than carnivores or pescatarians as they consume far more fruits and vegetables and less processed foods. However, those following a diet should be aware of the deficiencies that could crop up by following such a lifestyle. By noticing any issues and supplementing correctly, they should be in excellent health.