Following A Plant-Based Diet For PCOS – Can It Help?
June 10, 2022
With plant-based eating on the rise, we are hearing more questions about whether following a plant-based diet for PCOS can help with symptoms.
Polycystic Ovarian Syndrome (abbreviated as PCOS) has been around for a long time but has only recently been gaining more attention as we learn more about it.
PCOS is a hormonal condition affecting around 12–21% of women of reproductive age. However, this number is likely much higher with up to 70% of women with the condition remaining undiagnosed (1).
The exact cause of PCOS is still unknown, but it is likely due to a mix of genetic, environmental and lifestyle factors. These drive a combination of hormonal imbalances and metabolic issues that result in a collection of different symptoms that you may experience (2).
Polycystic refers to ‘many cysts’, which, when paired with the word ‘ovarian’, essentially means many cysts within the ovaries. However, this is only one of a collection of symptoms you may experience. In fact, some women may not even have any ovarian cysts present.
- Irregular or absent menstrual cycle
- Hirsutism – an abnormal amount of hair on body parts typically associated with males only e.g. face and chin, caused by higher than normal levels of male hormones such as testosterone
- Acne on the face, chest and/or upper back
- Hair loss and thinning similar to male-pattern baldness
- Weight gain or difficulty losing weight
- Darkening of the skin in the groin or underneath the breasts
- Anxiety and depression
- Sleep apnoea
PCOS also can cause metabolic problems such as hyperlipidaemia (i.e. high levels of fats in the blood such as cholesterol) and insulin resistance (more on this later). This means that women with this condition are also at increased risk of developing other health conditions such as diabetes and heart disease (3).
How is PCOS diagnosed?
As it is still a relatively new condition and there is no one specific presentation, diagnosis comes with a few challenges. This means that unfortunately for many sufferers, diagnosis often comes after years of misdiagnoses and symptom dismissal.
Currently, the most widely accepted diagnosis method is the Rotterdam Criteria (1). This requires at least 2 of the following to be present:
- Lack of ovulation causing an irregular or absent menstrual cycle
- Presence of hyperandrogenism that may be confirmed by either:
- Hirsutism and/or
- Excess production of male hormones (e.g. testosterone) detected via blood test
- Polycystic ovaries detected by an ultrasound
Misdiagnosis: is it PCOS or hypothalamic amenorrhea?
If you have been given a PCOS diagnosis or think you may have it based on an irregular or missing menstrual cycle, it may be worthwhile ruling out hypothalamic amenorrhea first as these two conditions can often be misdiagnosed.
Hypothalamic amenorrhea (HA) is a condition characterised by losing one’s regular menstrual cycle for longer than three months, or losing an irregular menstrual cycle for longer than six months. This may be driven by inadequate calorie intake, too much exercise, high amounts of stress, or a combination of these factors.
As both conditions are characterised by a missing or irregular menstrual cycle, and have no easy method for diagnosis, they can be easily misdiagnosed.
However, distinguishing between these two diagnoses is important as treatment strategies are very different and often even contradict each other.
You can read more about HA and getting your menstrual cycle back in one of our earlier blog posts.
Treatment approaches for PCOS
Currently there is no cure for PCOS. Instead, treatment options focus on managing your specific symptoms e.g. balancing hormones, improving insulin resistance, optimising fertility and improving energy levels.
Current management options include diet and lifestyle changes, supplements and medications. The exact cocktail of strategies that work are often highly unique to each person and it can take a bit of trial and error to find the right approach for you.
Four dietary strategies for tackling PCOS
When it comes to diet, research is still pretty much in its infancy and there is currently no ‘best PCOS diet’. That being said, there is research supporting a few different diet-related strategies that are worth trying.
1: Opt for low GI carbohydrates
Glycaemic index (GI) is a system that ranks carbohydrate-rich foods based on how they affect our blood glucose (i.e. blood sugar) levels after we eat them. Essentially, high GI foods will raise our blood sugar levels quickly after we eat them, whereas low GI foods have the opposite effect.
When our blood sugar levels rise, the body produces a hormone called insulin that helps to transport the sugars from our bloodstream into our cells, either for use as energy, or to store for future use. This means that high GI foods can cause quite a high insulin response, whereas low GI foods result in a slower insulin release.
But how does this help with PCOS?
As mentioned previously, insulin resistance is one of the many symptoms of PCOS and it is pretty common, affecting about 65-70% of people with the condition (4).
In simple terms, insulin resistance is when the body doesn’t respond as well as it should to insulin after meals. This means that it is much harder for us to lower our blood sugar levels after meals. Consuming lower GI foods that lead to a slower rise in blood sugar levels is therefore easier for the body to deal with which can have many positive flow-on effects.
In fact, a 2013 review that looked at the impact of different diet patterns on a variety of different PCOS symptoms found that a low GI diet may have some benefits. In particular, this pattern of eating improved menstrual cycle regularity, lowered cholesterol and improved quality of life (5).
It can also reduce your risk of developing type 2 diabetes further down the line, which is another positive considering PCOS is also unfortunately a risk factor for diabetes.
A few simple swaps to reduce glycaemic index include:
- Swap short grain rice (e.g. Jasmine rice) for long-grain varieties such as Basmati, Doongara or wild rice
- White bread products for grainy/seedy loaves or sourdough
- Fruit juice for whole fruit
- White pasta for legume-based based e.g. chickpea, edamame or red lentil pasta
- Standard breakfast cereal for oats or Weetbix
Plus, pairing your carbohydrate-rich foods with a source of healthy fats (e.g. avocado, olive oil or nuts and seeds) and/or protein such as tofu or tempeh can also help to lower the GI of your meal or snack by slowing down the rate of digestion. For example:
- Choose a nut butter or avocado to spread on your toast rather than jam
- Dip crackers in avocado or hummus
- Add tofu into sandwiches and wraps
- Blend nuts/seeds, silken tofu or protein powder into fruit smoothies
Beyond GI, it is probably important to mention the impact of glycaemic load (or GL). Glycaemic load is different to GI in that it takes into consideration how much carbohydrates are in the whole meal or snack you are eating. So, the more carbohydrates in a meal, the higher the GL.
This means it is helpful to consider both the quality and quantity of carbohydrates on your plate to assist with blood sugar management. We often recommend allocating 1/4 of your plate to carbohydrate foods, with another 1/4 filled with protein foods and 1/2 plate of non-starchy fruit or vegetables.
Bear in mind that everyone’s nutrition needs can be different, so it can be helpful to work with a dietitian for individual advice.
2: Try an anti-inflammatory or Mediterranean-style diet
Anti-inflammatory patterns of eating, such as the Mediterranean diet, are commonly praised for a myriad of benefits for the brain, heart and mental health. The Mediterranean diet has also been linked to improving a range of different chronic conditions including PCOS.
To give you a quick run-down on what a Mediterranean-style diet involves:
- Including plenty of whole foods such as fruits, vegetables, beans and legumes, whole grains and healthy fats such as nuts, seeds, extra virgin olive oil and oily fish
- Meat, poultry, eggs and dairy are only consumed in small to moderate amounts alongside more processed foods such as chips, cakes, biscuits and other sweet/savoury snack foods
In terms of its benefits for PCOS, there is a wealth of research suggesting potential benefits for this eating style to improve insulin sensitivity, fertility outcomes and reduce testosterone levels as well as making it easier to maintain a body weight that is right for you (6, 7, 8, 9).
Outside of these benefits, there are strong links between following a Mediterranean diet and improvements in anxiety and depression, which are common with PCOS (10).
3: Fill your plate with antioxidant-rich foods
Antioxidants are naturally occurring components in plant foods that help them to fight off dangers such as pests, disease and other damage when growing in the wild. Not only do antioxidants help protect the plants themselves, but these protective properties even extend to humans when we eat them by helping to reduce inflammation in the body.
This is especially beneficial in PCOS as research has found that consuming a diet rich in antioxidants can help reduce insulin resistance and high levels of androgens such as testosterone. This is likely due to the fact that women with this condition are more likely to have higher levels of inflammation and lower levels of circulating antioxidants in the body (11).
Including a wide variety of colourful fruit and vegetables in each meal is a great start to getting in more antioxidant-rich foods. In particular, add in more dark-coloured varieties such as berries, red/black grapes, beets, purple cabbage and eggplant.
4: Include omega-3 rich foods daily
Omega-3s get a mention in many of our blog articles, and for good reason too!
Omega-3s have a myriad of health-promoting benefits and there is some evidence to suggest that helping with PCOS management may be one of them. Research into the benefits of omega-3s for PCOS is still quite limited but a 2018 review had promising conclusions, finding that omega-3 intake was associated with improved insulin sensitivity and blood lipid levels (12).
Omega-3s have also been linked to lowering testosterone levels and improving menstrual cycle regularity (13).
Plant-based sources of omega-3s to add to your diet include walnuts, chia seeds, flax seeds and hemp seeds. Some easy tips for adding in omega-3s include:
- Add chia or flax seeds into porridge
- Top toast and salads with hemp seeds
- Include walnuts into trail mix as an easy snack
- Mix chia or hemp seeds into homemade muesli bars or bliss balls
- Add in chia pudding as a snack or breakfast option
- Blend chia, flax or hemp seeds into smoothies
Omega-3 supplementation may also be of benefit, especially for plant-based eaters, with more on this later.
Is there research to support following a plant-based diet for PCOS?
Currently, there is very little research into following a plant-based diet for PCOS. However, you may have noticed that many of the strategies we mentioned above are pretty well aligned with a more plant-based way of eating.
For example, vegan or vegetarian diets focused on consuming mostly plant foods are generally high in fruits, vegetables and whole grains which are our richest sources of antioxidants. They are also high in fibre and involve eliminating (or even just reducing if you aren’t a strict vegan) the biggest sources of saturated fats (‘not so healthy’ fats) in the diet which include full-fat diary, red meat and processed meats.
This is great for helping reduce inflammation and is also protective against both diabetes and reducing cholesterol levels.
However, on the flip side, following a plant-based diet can also have a few challenges. The main contradiction between a plant-based diet and a PCOS-friendly diet is the carbohydrate content.
As many of our plant proteins such as beans and legumes are much richer in carbohydrates than non-vegan proteins such as meat, eggs and dairy, plant-based styles of eating are naturally higher in carbohydrates.
This can be a challenge if you are also struggling with insulin resistance. However, as mentioned previously, foods such as beans, legumes and whole grains tend to be lower GI due to their high fibre content. If included on the plate in appropriate portions, this can still support blood sugar management.
Additionally, as they involve cutting out oily fish, our best source of omega-3s, plant-based diets can also often lack this critical nutrient which as we discussed is especially beneficial for PCOS.
Supplements for PCOS
Whilst as dietitians we always champion a food-first approach, when it comes to PCOS there is evidence to suggest that there are some supplements which may also be of benefit.
Currently, inositol has the strongest base of evidence supporting its benefit for PCOS. The current consensus is that a dose of 2-4mg per day may improve insulin sensitivity, lower testosterone levels and optimise fertility (14, 15).
We already have a whole blog post dedicated to PCOS, inositols and fertility which you can check out here.
As mentioned previously, there is emerging evidence for the role of omega-3s in improving insulin sensitivity, blood lipid levels, testosterone levels and menstrual cycle regularity in PCOS.
Whilst we can get omega-3s through the diet, this can be more challenging on a plant-based diet where good quality sources of this nutrient are limited. A plant-based omega 3 supplement containing algae oil may therefore also be of benefit for some people.
You can read our article about omega-3 on a vegan diet here.
It seems that there may also be some potential for cinnamon supplementation. A pilot study in 2007 had promising results with 8 weeks of daily oral cinnamon intake leading to significant improvements in insulin sensitivity in women with PCOS (16). Plus, a more recent study in 2014 found that cinnamon supplementation was able to improve menstrual cycle regulation (17).
As research is still limited, rather than starting on a supplement right away, we recommend beginning by adding more cinnamon into your diet by adding it into your oats or smoothies, sprinkling over toast with nut butter or adding it into your morning coffee.
In relation to PCOS, supplementation of 50mg zinc per day has been linked to improving hair loss, promoting hair growth and improving insulin resistance (18, 19). Although there are many plant-based sources of zinc in the diet such as beans and legumes, whole grains and sundried tomatoes, it is very unlikely that you would be able to meet the studied 50mg/day target through diet alone.
Research has found a link between PCOS and vitamin D deficiency. However, it is unknown if PCOS puts you at greater risk of deficiency or if it is the other way around and a vitamin D deficiency is a risk factor for PCOS (20, 21).
Either way, if you are vitamin D deficient, a supplement will likely be of benefit. Especially if you are looking to conceive, as there is quite a bit of research supporting the importance of good vitamin D status for optimising your fertility (22, 23).
However, when it comes to vitamin D supplementation, it only appears to be beneficial if you are deficient. Therefore, we recommend to ‘test, not guess’ before starting on a supplement.
The final supplement which may offer some benefit is chromium. If you haven’t heard of it before, chromium is a trace mineral in the diet meaning that we find it only in small amounts. A 2017 review on chromium supplementation found that it may potentially be beneficial for improving insulin resistance and reducing testosterone levels in PCOS (24).
As with all supplements, it is important to remember that these supplements should be taken on a case-to-case basis and it is recommended that you speak to your GP or dietitian before starting on any new supplements to make sure you are taking the ones that are right for you.
Whilst there is a growing pool of research supporting the role of diet and supplements in managing PCOS symptoms, this is still in it’s infancy.
There is some evidence to support following a plant-based diet for PCOS. If you are currently struggling with PCOS, the main dietary factors which may play a beneficial role include choosing lower GI carbohydrates, eating more whole and antioxidant-rich plant foods and adding in more omega-3 rich nuts and seeds.
It may also be worthwhile to look into some potential supplement options with a doctor or dietitian as well.
Speaking with an experienced health professional such as a dietitian at the PNW clinic can help make this process easier. Our dietitians are experienced and passionate about the areas of plant-based nutrition and women’s health.
This article was written by PNW Clinic dietitian Georgia D’Andrea.