Polycystic ovary syndrome (PCOS) is a common hormonal condition affecting women of reproductive age. It affects individuals in different ways and in varying severity, characterized by hormonal imbalances and metabolic disruption. PCOS affects approximately 5-10% of females aged 15-44. Symptoms of PCOS include:
- Irregular or absent periods
- Signs of hyperandrogenism (too much male hormone, including testosterone) e.g. acne, excess facial and body hair, male-pattern baldness.
- Polycystic appearance of the ovaries on ultrasound scan - this means lots of small ‘cysts’ on the ovaries which are actually underdeveloped eggs that the ovary was unable to release.
- Ovarian cysts or growths
- Reduced or no menstruation
- An increase in androgen hormones
PCOS can lead to other serious health challenges, such as diabetes, cardiovascular problems, depression, and a higher risk of endometrial cancer.
Many women with PCOS have insulin resistance, which means the body’s cells don’t respond properly to insulin resulting in elevated glucose levels. About 70 percent of women with PCOS have a degree of insulin resistance, insulin being the hormone that regulates our blood sugar. The body makes more insulin to try and compensate, which causes the ovaries to produce lots of testosterone, which is the root of many of the symptoms.
While there is currently is no cure for PCOS, many of the symptoms caused by PCOS can be managed through diet and lifestyle changes. In fact, losing just 5% of body weight can improve symptoms and boost fertility. Because insulin plays an important role in PCOS and its metabolic features, controlling the disease with diet is the best step for people who want to manage PCOS and its associated symptoms.
One of the most researched diets in managing PCOS is a low glycemic index (GI) diet. That’s because beneficial effects have been observed in managing numerous PCOS symptoms, such as insulin resistance, carbohydrate cravings, and potentially even infertility.
Read also: PCOS Diet Recipe Guide
Understanding the Glycemic Index (GI)
The glycemic index (GI) is a scale from 1-100. The lower the score, the longer that food takes to raise a person’s blood sugar levels. The GI is a ranking system which indicates how quickly your blood sugar rises after eating different carbohydrates. The glycemic index of a food measures how quickly that food raises blood sugar levels after eating. Foods can be categorized as having a low, medium, or high glycemic index.
Generally, low GI foods are digested and absorbed into the blood more slowly and cause a gradual rise in blood sugar levels, compared to high GI foods which are broken down quickly and cause a rapid increase in blood sugar levels. In foods with a low glycemic index, glucose is slowly released into the bloodstream after being digested. This can help prevent sudden rises in blood sugar.
The GI scale runs from 0 to 100, with 100 being pure glucose, causing the biggest spike in blood glucose.
Factors Affecting the GI of Food
As with many things diet-related, what makes a food high or low in GI is complex and dependent on multiple factors. Factors that impact the GI of food include:
- Nutritional content: Foods that contain nutrients such as fibre, fat and protein lower the GI of foods as the digestion and absorption of these nutrients slows the digestion and absorption of glucose. So individual foods, as well as overall meals, with a lower carbohydrate content and higher protein, fibre or fat content are likely to have a lower GI.
- Food processing: Processing grain products such as bread, pasta and rice, increases their GI.
- Cooking time: The longer a food is cooked for, tends to increase GI as heat breaks down the carbohydrates in food making them faster to digest and absorb.
Benefits of a Low GI Diet for PCOS
Following a low glycemic index (GI) diet is recommended for people with PCOS to help regulate their periods (menstrual cycle) and decrease the risks of insulin resistance. Consuming a low GI diet has been shown to increase insulin sensitivity, mental health and decrease acne in people with PCOS.
Read also: Managing PCOS with Diet
One recent meta-analysis reviewing eight studies found that a low GI diet may play a significant role in improving PCOS symptoms, such as acne, body hair and emotional health. Another systematic review and meta-analysis reviewing eight trials found a low GI diet to improve biochemical features of PCOS such as glucose regulation, insulin sensitivity, blood cholesterol and testosterone. One trial of 96 women with PCOS found that those who followed a low-GI diet for twelve months also had improved diet-metformin interaction and menstrual cyclicity compared to those following a conventionally healthy diet.
A meta-analysis has shown that LGD can play a significant role in reducing the risk and improving the clinical and biochemical features of PCOS. Generally, insulin resistance is present in both obese and non-obese patients with PCOS. Because insulin plays an important role in PCOS and its metabolic features, controlling the disease with diet is the best step for people who want to manage PCOS and its associated symptoms.
Impact on Insulin Resistance
A low GI diet reduces the risk of type 2 diabetes as well as the development of heart disease. The biggest culprit of insulin resistance is eating a lot of processed foods and simple carbs. These carbs are made of sugars, such as fructose and glucose, and can cause a sudden rise in blood sugar and insulin production, which can lead to health issues.
There is some research that shows eating a higher protein diet when you have PCOS can help improve insulin resistance along with a reduction in carbohydrates. Healthy fats, such as monounsaturated and polyunsaturated fats, can help improve insulin resistance, according to research. Diets high in trans and saturated fats can increase insulin resistance and inflammation in the body.
Managing Blood Sugar Levels
In foods with a low glycemic index, glucose is slowly released into the bloodstream after being digested. This can help prevent sudden rises in blood sugar. Whole grains are processed in the body slower than simple, refined carbs. They do not cause spikes in blood sugar and insulin, and they have a lower glycemic index.
Read also: Delicious PCOS Diet
Too much sugar can cause inflammation in the body, which can negatively affect those with PCOS.
Improving Fertility
Previous evidence found that a LGD may have benefits for individuals undergoing in vitro fertilization (IVF) and natural fertility . Studies demonstrate that a high-fiber, low-glycemic-index diet such as the DASH diet will result in an overall weight loss and a reduction in insulin resistance.
Reducing Androgen Levels
In PCOS increasing the pulsatility of luteinizing hormone (LH) levels regarding both frequency and amplitude, increases theca cell production of androgens, while relatively low FSH secretion impairs follicle maturation and consequently ovulation.
Supporting Weight Management
Weight loss in those who are overweight, weight management in those who are not, and reducing central adiposity (fat tissue around the stomach & hips) can help to reduce insulin resistance, which as mentioned is the driver of the hormonal imbalance that characterises the disease. Fat tissue also makes its own testosterone so it’s a way of reducing that, too.
While weight loss of even 5-10 per cent of total body weight has been shown to improve hormone profiles, menstrual regularity as well as long-term outcomes, the evidence to suggest how best to do this is lacking.
Foods to Include in a Low GI Diet for PCOS
Choosing low GI, high fibre foods like beans, lentils, chickpeas, brown pasta and rice, whole grain bread, fruits and vegetables as the ‘base’ of the majority of your meals may be beneficial for your PCOS symptom management.
Examples of foods to include in a PCOS-friendly diet include:
- Non-starchy fruits and vegetables
- Whole grains
- Legumes, such as lentils and beans
- Nuts
- Seeds
- Fatty fish, including salmon, tuna, sardines, and mackerel
- Kale, spinach, and other dark, leafy greens
- Dark red fruits, such as red grapes, blueberries, blackberries, and cherries
- Broccoli and cauliflower
- Dried beans, lentils, and other legumes
- Healthy fats, such as olive oil and avocados
- Nuts, including pine nuts, walnuts, almonds, and pistachios
- Dark chocolate in moderation
- Spices, such as turmeric and cinnamon
Foods to Limit or Avoid
People with PCOS can benefit from avoiding foods that increase the risk of diabetes, cardiovascular disease, obesity, and other common health issues.
High GI foods include sugary foods and drinks, potatoes, white bread and white rice.
These include:
- Refined carbohydrates, such as mass-produced pastries and white bread
- Fried foods, such as fast food
- Sugary beverages, such as sodas and energy drinks
- Processed meats, such as hot dogs, sausages, and luncheon meats
- Solid fats, including margarine, shortening, and lard
- A high intake of red meat, such as steaks, hamburgers, and pork
- Foods with high levels of added salt or sugar
- Other highly processed foods
Drinking soda might seem obvious when it comes to sugary-beverage examples, but you may not realize your morning smoothie, especially if it comes from a bottle at the store, can still contain enough sugar to spike your blood sugar. Instead, stick to eating whole fruits instead of juices.
Sample Low GI Meal Plan
Here are some low GI meal plan ideas:
- Breakfast: Muesli, yoghurt and berries. Swap your morning cereal for a low/ no added sugar, high fibre alternative, such as muesli. Serve with healthy fats and protein such as full fat yoghurt and nuts to reduce the GI of the meal.
- Lunch: Chicken and avocado pita. Increase the amount of healthy fats in your lunch by adding avocado. Aswell as nutritious value, it adds a lovely creamy texture. Swap white pita bread for a wholemeal alternative to increase the fibre and reduce the GI.
- Dinner: Sausage and bean casserole. Throw all your favourite root vegetables such as carrots, onions, celery and parsnip, into an oven proof dish (or slow cooker) with stock, a tin of tomatoes, butter beans and sausages. Cook for a few hours allowing all the different flavours to combine.
Have a go at experimenting with some of the other examples of low GI ingredients to come up with your own daily meal plan!
Additional Considerations
Vitamin and Mineral Deficiencies
Vitamin D deficiency is common in individuals with PCOS. Vitamin B12 deficiency is common in individuals with PCOS who take the medication metformin.
Healthy Fats
Getting enough omega-3 fatty acids in your diet can decrease your risk of insulin resistance, type 2 diabetes, and heart disease. Fat in your diet provides your body with energy, but some fats are better than others. Healthy fats, such as monounsaturated and polyunsaturated fats, can help improve insulin resistance, according to research.
The Importance of Fiber
The other concern regarding long-term use of a ketogenic diet is the low fibre content. Fibre is a nutrient that most of us don’t consume in large enough quantities, with low fibre intake correlated with worsening insulin resistance and higher androgen (male hormone) levels in women with PCOS. High fibre foods have been shown to definitively improve blood glucose control, blood cholesterol, healthy bowel movements and keep you fuller for longer.
Fruits and vegetables are a great way of getting more fibre. I tell my patients to make their plate as colourful as possible.
Lifestyle Changes to Complement a Low GI Diet
Your diet is only one part of managing life with PCOS. Lifestyle measures can also help people with PCOS manage the condition. Research suggests that combining dietary measures with physical activity may have the following benefits:
- Weight loss
- Improved insulin metabolism
- More regular periods
- Reduced levels of male hormones and male pattern hair loss
- Lower cholesterol levels
Exercise
Exercise can help lower levels of blood sugar, so regular exercise can go a long way in treating or preventing symptoms of PCOS. It can help your body produce less insulin, which in turn tells your body’s cells to reduce your blood sugar. This is so important to build and maintain lean muscle, which helps to reduce insulin resistance. Exercise can also increase sex-hormone binding globulin (SHBG) levels, a hormone that is able to bind testosterone, making it less potent. There’s no best exercise for PCOS. I tell my patients the best exercise is the one that they enjoy and the one they’re going to stick to for the long-term. The only thing I would advise against is excessive amounts of high-intensity interval training. It’s great for 15-20 minute bursts a few times per week, but not long daily sessions, because that adds too much stress on your body and can also negatively impact your hormones.
Sleep
Get enough sleep: Unfortunately, if you have PCOS, you may notice you have difficulty sleeping. Some people with PCOS experience insomnia and sleep apnea. Sleep hygiene is important to ensure adequate sleep quantity and quality, the lack of which can further disrupt hormone function.
Stress Management
Managing your stress: The symptoms of PCOS can be stressful. Taking steps to reduce your stress can help manage your symptoms and positively impact your health overall. Try practicing yoga, meditation, or deep-breathing exercises. Journaling or taking a daily walk in nature can also help. This can drive the adrenal glands to make more testosterone. Of course, we can’t remove stress entirely, but not all stress is psychological, and lack of sleep and extreme, excessive exercise are two common examples of stress that we can try and eliminate.
Studies also suggest behavioral strategies can help people reach their weight management goals. This, in turn, can help manage PCOS symptoms. These practices include:
- Goal setting
- Social support networks
- Self-monitoring techniques
- Caring for mental well-being
Reducing stress through self-care practices, such as getting enough sleep, avoiding overcommitment, and making time to relax, can also help a person manage PCOS.
Other measures
- Yoga: This can be a great way of combining exercise and mindfulness, and in fact, a study of 90 girls with PCOS in India showed that practising one hour a day for 12 weeks not only improved their menstrual cycle regularity, but also blood hormone profiles.
- Smoking: Given the increased risk of heart disease with PCOS and from smoking - it’s a ‘no’ from me!
Limitations of a Low GI Diet
Although looking at low GI foods may be useful, in some instances it can be misleading. Some foods with a high GI may be more nutrient dense than a low GI food. For example, crisps vs. potatoes, and chocolate vs. watermelon. Both crisps and chocolate have a lower GI compared to potatoes and watermelon which both have a higher GI. This is because of the fat content in chocolate and crisps which slows the release of glucose into the bloodstream. It may therefore be beneficial to also consider the other nutrients in foods such as fat, protein and fibre.