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Common Nutritional Deficiencies With a Plant-Based Diet

The plant-based, or vegan, diet boasts a whole host of amazing health benefits—from reducing your risk of certain cancers to aiding weight loss and promoting heart health. 

However, any diet that lacks certain food groups, in this case animal derived products, can end up being lacking in certain essential nutrients. 

Whilst it is possible to get all of your essential vitamins, minerals and food groups from a plant-based diet, it requires careful planning and smart supplementing to ensure your nutrition is well rounded. 

In this article we’ll take a look at some of the most common nutritional deficiencies in a plant-based diet, why they occur and how to avoid them. 

What is a nutritional deficiency?

Nutritional deficiencies occur when the body isn’t getting an adequate supply of certain nutrients. Deficiencies can also increase our risk of diseases and compromise our immune systems. 

They can result in unwanted symptoms, like fatigue, muscle weakness, sleep disturbance, decreased bone density and reduced cognitive function. 

Common deficiencies with a plant based diet

There are a number of nutrient deficiencies that are common in those who follow a plant-based diet, but not everyone who is vegan will experience these deficiencies.


Omega-3 fatty acids are really important for heart and brain health. There are three types of omega-3’s: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). ALA can be found in high amounts in nuts, seeds, plant oils and fortified foods. DHA is mainly found in fatty fish, like mackerel and salmon. 

The body can convert ALA into DHA and EPA in small amounts, but this is usually not very efficient. Therefore lots of people eating plant-based diets struggle to get adequate amounts of DHA. 

DHA deficiency can have adverse effects on mental health, including brain function and fetal brain development during pregnancy.  Luckily, DHA can be found in certain types of microalgae, like those used to make our NothingFishy Algae Omega-3 capsules

Vitamin B12

Vitamin B12 is an essential nutrient involved in developing red blood cells, maintaining nerves and supporting healthy brain function. 

Unfortunately, B12 is found almost exclusively in animal derived products, like dairy, meat, fish and eggs. Some plant foods contain trace amounts of B12, including nori seaweed, tempeh and shiitake mushrooms. However none of these foods provide adequate amounts of B12, which is why supplementing is essential. 


Iron is an incredibly important mineral that’s involved in a number of different bodily functions, including helping red blood cells carry oxygen around the body. 

Iron deficiency can cause symptoms like fatigue, weakness, difficulty concentrating and impaired brain function. In severe cases it can lead to anaemia. 

Plant based sources of iron are found in nuts, raisins, beans, lentils, spinach, peas and fortified cereals. But Heme iron is only found in meat, especially in red meats. Heme iron is much easier for the body to absorb than other non heme types of iron. 

This is why those following a plant based diet need to consume around twice the amount of non heme iron.

Vitamin D3

Vitamin D3 is important for immunity and promoting healthy bones by helping your body to absorb calcium. 

The body can make vitamin D3 from sunshine, which is why lots of people refer to it as the sunshine vitamin. Regardless of diet, it’s actually recommended that everyone in the UK should supplement with a Vitamin D supplement year round


Thyroid hormones T3 and T4, which are crucial for metabolism, are reliant on iodine for their production. Iodine deficiency can be common in those following a vegan diet and can eventually lead to hypothyroidism causing impaired thyroid function, extreme fatigue and weight gain. 

Some plant-based foods high in iodine are Irish Sea Moss, soy milk, potatoes, prunes, seaweed, and iodized salt.


Calcium is an important mineral for bone density, development and muscle function. Calcium is found in high levels in dairy products, but is also found in plenty of plants and legumes like broccoli, kale, chard, beans, peas and soy products. 

Smart supplementing 

When it comes to following a vegan diet, smart supplementing can go a long way. Boosting your intake of specific nutrients, that aren’t found in high concentrations in plants or vegan alternatives, is a smart way to ensure you’re covering your nutritional needs. 

Check out our Algae oil Omega-3’s, Vitamin D and Irish Sea Moss for vegan-friendly, sustainable supplements to help boost your nutritional intake and promote a well rounded plant-based diet.