PCOS and vegan diet: is plant-based better?

There have been many claims that many diets or ways of eating can help to reduce the symptoms of PCOS. Research has investigated the impact of a ketogenic diet, vegetarianism, high fat and low carb diets … the list goes on! More recently the question has been raised about whether PCOS and a vegan diet are linked.

What is PCOS?

PCOS is a collection of symptoms with metabolic and reproductive outcomes. Everyone who is diagnosed with PCOS presents differently but some symptoms include acne, oily skin, lack of or irregular periods, lack of ovulationexcess hair growth, insulin resistanceincreased testosterone levels and fertility issues.

What is a vegan diet?

First, let’s look at what the vegan diet actually is. The Vegan Society defines veganism as “a philosophy and way of living which seeks to exclude all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose”.

A vegan diet includes not eating anything derived from animals, including meat, dairy, eggs and honey. The diet consists of only plant-based foods, such as vegetables, fruits, nuts, seeds, and grains. There are many reasons why someone would decide to become vegan including health reasons, ethical reasons, or just personal preference.

What is the difference between a vegetarian and vegan diet?

The difference between a vegetarian and a vegan diet is a commonly asked question.

Vegetarians don’t eat any food products made from animals (including meat, fish, shellfish and crustacea) or animal by-products like gelatine or rennet. Whereas vegans don’t eat any animal products, animal by-products or food products that have come from animals (such as dairy and eggs).

What about a plant-based diet? Is that different to being vegan?

Yes! Being vegan involves not only omitting all animal products from the diet but also from their lifestyle (such as refraining from wearing leather, choosing not to use personal products that have been tested on animals etc.).

Whereas a plant-based diet is a concept of eating a diet that either entirely or mostly comprises plant foods. Lifestyle choices may or may not be influenced by someone on a plant-based diet.

Is there evidence that a vegan diet for PCOS can be beneficial?

As of yet, there has been very little research done on the link between the two and when trying to research the topic there has been no concrete evidence found to support any claims made. There have been no studies to confirm that a vegan lifestyle will help alleviate symptoms of PCOS.

One study assigned eighteen people with PCOS who were experiencing infertility were assigned either a vegan or low-calorie diet. This study found that short-term weight loss was achieved in the vegan group but this research did not measure anything related to symptoms of PCOS (such as inflammatory markers, androgen levels or fertility markers). This highlights how researchers equate weight loss to improved symptoms even though no correlations were measured.

PCOS is associated with low-grade chronic inflammation. In people with PCOS, inflammatory markers or their gene markers are often seen in higher quantities than in people without PCOS. An analysis of studies on plant-based diets (including vegetarian and vegan diets) found that a vegan diet was associated with lower levels of C-reactive protein (an inflammatory marker), compared to omnivores. No other effects were observed for all other inflammatory biomarkers. This research suggests that plant-based diets may be beneficial for low-grade chronic inflammation but much more research (especially on people with PCOS) is needed.

Plant-based diets are often higher in fibre. One study found that vegans eat 47g of fibre on average per day (the daily recommended amount is 30g). Fibre can be beneficial for PCOS because it slows down the absorption of glucose into the bloodstream. This may help with insulin levels and therefore insulin resistance which is a common symptom and driver of PCOS.

Considerations for people who follow a vegan diet

It is important to consider whether adopting a vegan diet will allow you to include all of the necessary nutrients our bodies need to function optimally. Many vegans often require supplementation of certain nutrients.


It is a common misconception that people on a vegan diet cannot consume enough protein. But because plant-based foods tend to have lower protein levels than animal products, more consideration and planning may be required.

Protein has many uses in the body including structure for our muscles and bones, fighting infection as well as growth and repair. In the UK, the recommended daily intake of protein is 0.75g of protein per kilogram of body weight.

There are many good plant-based protein sources including beans, lentils, chickpeas and soy. Brown or wholegrain carbohydrates plus nuts and seeds are also good protein sources.


Omega-3 is an essential fatty acid that is essential for a healthy immune system, brain, nerves, eyes and skin. Omega-3 fatty acids are abundant in foods like oily fish, but what about plant-based sources?

Good sources of omega-3 include walnuts, flaxseeds, chia seeds, hemp seeds, edamame, seaweed and algae. If you struggle to get enough omega-3 in your diet then an algae omega-3 supplement may be beneficial.

Vitamin B12

Vitamin B12 is a water-soluble vitamin which is essential for the metabolism of fatty acids and amino acids, blood formation and neurological function. B12 deficiency can occur if you are on a vegan diet because vitamin B12 is not found reliably in plant-based foods.

Plus, if you are taking the insulin sensitiser medication Metformin, you are at further risk of vitamin B12 deficiency. Supplement with a B12 supplement in capsule or spray form. Speak to your doctor if you are concerned about vitamin B12 deficiency and learn more about B12 and PCOS here.

This is not an exhaustive list of vitamins, minerals and nutrients you need to consider if you are going vegan. If it is accessible to you, speak with a nutritionist or dietitian with training in plant-based diets and PCOS. Check out our providers directory.

How to decide if a vegan diet is suitable for you

You know your body best and can make decisions that suit you and your values. If animal welfare, environmental concerns and sustainability are important to you then choosing a vegetarian, vegan or plant-based diet may be suitable for you. But, it is important to be aware that dietary considerations are required if you choose to go on a vegan diet for PCOS.

Main takeaways for PCOS and vegan diet

As outlined above, there are many reasons why someone may want to try veganism, however there is no concrete evidence currently that a vegan diet will be beneficial for PCOS management.

The main thing to remember is that everyone’s body is different, and what works for one person may not work for another. Consuming a balanced, sustainable diet you enjoy is what’s most important.

Alex Okell ANutr Founder and Editor

Founder and Editor | Registered Associate Nutritionist


Founder of Be The Collective LTD [The PCOS Collective & The Endo Collective] Alex Okell ANutr is a London-based reproductive health nutritionist with experience in research, private practice and digital media. She holds a Master’s degree in Nutrition from King’s College London and has co-authored papers with the University of Cambridge, King’s College London, The Food Foundation and the Food Standards Agency. Alex offers 1:1 PCOS support in our virtual PCOS clinic.

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