What Are The Negative Effects of a Vegan Diet?

Posted by Sayful-L-Islam Khan on

What are the negative effects of a vegan diet?

Whilst a vegan diet has many positive effects on our bodies unfortunately it’s not all good news. At Nutracity’s online vegan nutrition store we stock a lot of fantastic vegan products as part of our vegan products UK line, however, we do have to point out the negative effects of a vegan diet in order to give our readers and customers a balanced view on this topic. The first reason that a vegan diet does not automatically mean a healthy diet is because it does not exclude all unhealthy foods. It only excludes foods from or derived from animals, but a lot of unhealthy, processed foods would meet the criteria of a vegan diet as vegan diets do not exclude ingredients like sugar or gluten. As good sources of animal protein such as meat, fish, eggs and dairy are excluded from a vegan diet, a lot of vegans turn to legume and soy protein sources. Legumes have high levels of lectins and phytates – which are antinutrients. As these compounds are hard to digest, it can cause gut inflammation and lead to an increased risk of a leaky gut. Soy proteins can contain hight amounts of phytoestrogens, which in turn can affect the hormone balance in the body and can therefore affect an individuals mood or even metabolism.

There can also be a risk of anaemia due to low or no ingestion of heme iron from vegan foods. Plant based foods contain non-heme iron which is not absorbed as much in the body, therefore can lead to anaemic symptoms such as fatigue. On top of this, iron supplements tend to cause constipation so vegans are less likely to adhere to taking this which in turn can make symptoms worse. A decent omega-3 fatty acid intake has been shown to decrease the risk of depression. Unfortunately for vegans, the best source of this is from fish and fish oils therefore a vegan diet without omega-3 supplementation could increase a vegan’s risk of depression. Algae-based sources of omega-3 fatty acids are an option, but they can be expensive and hard to find. As mentioned in my previous blogs, one of the main risks of a vegan diet is a deficiency in vitamin B12. Unfortunately vitamin B12 is only available from animal foods, so I believe that a good vitamin B12 supplement is an absolute must on a vegan diet. Zinc, which is essential for the immune system is also low in vegan diets and therefore it is also recommended to supplement with zinc.

Another problem with a vegan diet is that there may be a risk of consuming too much carbohydrates. This is because, on a vegan diet, it is very hard to find foods that are just high in protein and nothing else. Whilst soy and legumes are high in protein, they can also have a fair amount of carbohydrates too. This can lead to an imbalance in the diet as well as imbalanced blood sugar levels. Protein has been proven to help with satiety and therefore helps with weight management. On the plus side however, there are plenty of vegan friendly protein powders, such as Nuzest Clean Lean Pea Protein.1 One study has found there to be a link between orthorexia nervosa and vegetarianism. Orthorexia nervosa is an eating disorder that involves an unhealthy obsession with eating healthily. This can lead to over-restriction, obsession and can in-turn also have social implications for the person affected also. The study found that vegetarianism was used to mask eating disorders and allowed the affected individuals to avoid certain products or situations related to food. So as a result, the diet was only followed to hide an underlying issue that families and friends could have detected earlier.2

Another common misconception is that all types of food in a vegan diet are good for the environment. In terms of environmental damage, nothing really compares to beef, lamb, pork, and dairy, however, this does not mean that all types of vegan food are good for the environment. One reason for this is the importation of out-of-season fruits and vegetables from other countries. For example, a study done at the University of Manchester found that, “asparagus eaten in the UK has the highest carbon footprint compared to any other vegetable eaten in the country, with 5.3kg of carbon dioxide being produced for every kilogram of asparagus, mainly because much of it is imported by air from Peru”. Another factor is artificial fertilisers, these account for at least 3% of global greenhouse gas emissions. This occurs from the production of these fertilisers which release carbon dioxide and methane into the atmosphere as well as the use of these fertilisers which release nitrous oxide into the atmosphere. Another example is that certain fruits and vegetables need to consume large amounts of water to ensure efficient growth of crops. Avocados for example need roughly 140 – 272 litres of water for a single avocado and a kilogram of mangoes needs 686 litres of water. These fruits not only need a lot of water to grow, but also to maintain as after harvesting, hot water is used to disinfect these fruits. So, a high amount of waste, special storage conditions and packaging needed for avocados ensures that this fruit as a very high carbon footprint of 2.2kg of CO2/kg and 4.4kg of CO2/kg for mangoes. Another factor is deforestation, an increased demand for cocoa for example has resulted in an estimated loss of 2-3 million hectares of tropical rainforest between 1988 and 2008. The location of this deforestation has concerned environmentalists as it is happening in sensitive biodiversity hotspots in the rainforests of the Amazon, West Africa and South East Asia.3

So to sum up, just like most things in life, there are positive effects and negative effects to a vegan diet. I feel that it is important to be aware of all aspects of any type of diet that you may decide to embark on, and by doing this, we can help to minimise the bad effects on our body and on then environment. It is important not to turn a blind eye to the negative consequences of anything, this way, we can do what we can to mitigate these, in this instance, a good supplementation of vitamin B12, omega-3 fatty acids, zinc and vitamin D is a good place to start, all of these can be purchased from Nutracity’s online vegan nutrition store.




1) https://www.cleaneatingkitchen.com/vegan-diet-dangers-health/

2) https://pubmed.ncbi.nlm.nih.gov/29432508/#:~:text=Some%20scientists%20believe%20that%20vegetarians,or%20situations%20related%20to%20food.

3) https://www.bbc.com/future/article/20200211-why-the-vegan-diet-is-not-always-green