Which diet works best to manage PCOS symptoms?
According to the 2023 International Evidence-Based Guidelines for the Assessment and Management of PCOS, whilst there are benefits to losing weight, there is a lack of significant clinical evidence on the effectiveness of specific lifestyle interventions within the PCOS population.
There is a plethora of well-meaning and sometimes contradictory advice around managing PCOS symptoms with diet. In this article we explore the link between PCOS and Diet.
The typical Western diet is characterized by excess calorie intake[1] and high intake of foods high in sugar, fat and salt, including:[2]
Pre-packaged and fried foods, also often high in trans fats;
Animal protein, especially red meat and processed meats such as hot dogs;
Refined carbohydrates, especially in carbonate drinks, cakes and sweets; and
High-fat diary products and high-fructose (sugar derived from fruits) products.
This “normal” diet is also characterized by a lack of fiber (derived from whole grains, fruits and vegetables) with one study finding that 95% of people in the US do not consume enough.
Whilst this typical diet strays far from government guidelines on a healthy diet, it’s important to recognize that the guidelines themselves are not an ideal standard based on nutritional science but the product of historical context and food industry politics. The original US food guidelines were released in the 1940s to help with food rationing during World War II and Sweden released the original “Food Pyramid” in the 1970s as a way of coping with escalating food costs.[3]
The updated “MyPlate” model in the US still falls short of reflecting what we now know about a healthy diet and compares unfavorably to how these guidelines have evolved in other countries such as Australia, mediterranean Europe and India.[4]
For those seeking to manage their PCOS condition with dietary modifications it is important to recognize that:
Small, common-sense, sustained improvements to your lifestyle (e.g., drink more water, eat more fruits and vegetables, eat less processed foods) can make tangible improvements to your health and wellbeing;[5]
In general, evidence on the benefits of specific diets for a general population may not be applicable to a specific individual with PCOS and, in some cases, may focus inherently on short-term gains rather than sustained improvements in health;[6]
There is a lack of strong research evidence on the benefits of specific diets for individuals with PCOS, often limited to just one or two small studies if any; and
Overly restrictive diets can have a negative impact on one’s health with, for example, insufficient calorie intake associated with a compromised immune system and can also contribute to disordered eating behaviors[7] (which individuals with PCOS are an increased risk for).
At its core, PCOS is associated with abnormal functioning of the system of hormones that connects the hypothalamus, the pituitary and the ovaries (the HPO-axis).[8] PCOS is associated with hyperandrogenism (HA) or androgen excess (AE), elevated levels of androgens in individuals assigned female at birth.
Elevated androgens disrupt the way that adipose tissue metabolizes glucose. The adipose tissue produces less adiponectin, a hormone that helps with insulin sensitivity and inflammation, and more leptin, a hormone that causes you to feel hungry in efforts to maintain enough fat stores for long-term health. As a result, 65-70% of individuals with PCOS develop insulin resistance (IR).[9] In another study insulin resistance was shown to affect up to 95% of individuals with PCOS who are overweight and up to 75% of individuals who are lean.[10]
IR makes it more difficult to maintain a healthy weight and can lead to weight gain. Obesity, particularly the build up of fat around the abdomen (central adiposity), interferes with the production of sex hormones, increasing the level of androgens[11] and therefore exacerbating the effects of PCOS.
In general, a low-glycemic index (low-GI) diet is often recommended for individuals with insulin resistance. High-GI foods contain simple carbohydrates, forms of sugar that are quickly/easily broken down into glucose.[12] When you eat high-GI foods, your blood glucose levels therefore rise quickly or “spike” and the pancreas has to produce a lot of insulin to bring the blood sugar back down.[13] High-GI foods include many foods that you would commonly view as “carbs”, i.e., white bread, potatoes, cereals, cakes and cookies and some fruits such as watermelon and dates.[14][15]
In contrast, low-GI foods are made up of proteins and/or fats or contain complex carbohydrates, forms of sugar that take longer to break down into glucose and don’t place as much demand on the pancreas.[16]2 Low-GI foods include beans and legumes, fruits such as apples and berries, non-starchy vegetables, nuts and animal protein.[17]
There are a variety of different diets which are based on restricting carbs to varying degrees; these include:
Mediterranean Diet: focuses on plant-based foods and healthy fats;[18]3
Mediterranean Low-Carb Diet: combines the Mediterranean diet with restricted carbs;[19]
Slow Carb Diet: relatively simple diet plan with low-carb meal plans;[20]
High Fiber Diet: focused on increasing fiber in diet (and thereby displaces high-GI foods);[21]
Portfolio Low-Carb Diet (PLCD): plant-based diet that is comprised of 40% carbs, 20% protein and 40% fat and includes five cholesterol-lowering foods and nutrients (plant protein, viscous fiber, omega-3 fatty acids, L-arginine and phytosterols);[22]
Low-Carb Diet: consisting of 25% or less of calories derived from carbs;[23]
Very Low-Carb Diet: consisting of 10% or less of calories derived from carbs;[24]
Low-Carb, High-Fat (LCHF) Diet: 5-10% of calories derived from carbs and 65-70% from fats;[25]
Ketogenic (Keto) Diet: consisting of 10% or less of calories derived from carbs and replacing with calories derived from fats;[26][27]
Atkins Diet: phased diet plan which severely restricts carbs, particularly in early stages, and uses a tracking method of “net carbs” based on total number of carbs minus fiber content in grams;[28]
South Beach Diet: consisting of restricted intake of carbs with a focus on lean protein and healthy fats;[29]
Paleo Diet: theoretically based on an eating plan that humans might have consumed during the Paleolithic Era (2.5 million to 10,000 years ago) with a focus on fruits, vegetables, lean meats, fish, eggs nuts and seeds;[30]
Whole30: phased diet plan which focuses on complete elimination of processed foods, legumes and dairy for the 30 straight days;[31] and
Dukan Diet: phased diet plan focused on weight loss through pure protein and then re-introducing vegetables and small quantities of other, restricted foods.[32]
Individuals with PCOS are often at risk of some nutritional deficiencies which may increase underlying health risks; these include:
Vitamin B6, B9 (folic acid) and B12: PCOS is associated with deficiencies, but no causal link has yet been found;[33]
Vitamin C: PCOS is associated with chronic, low-grade inflammation so that Vitamin C, that acts as an antioxidant, is depleted combatting free radicals (highly reactive, unstable molecules);[34][35]
Vitamin D: PCOS is often associated with an accumulation of adipose tissue (body fat) which stores Vitamin D and therefore makes it less available in the blood;[36]
Magnesium: PCOS is associated with hyperinsulinemia, elevated levels of insulin in the blood,[37] and it has been theorized that magnesium deficiency is linked to elevated insulin levels;[38]
Selenium: similar to Vitamin C, selenium is an anti-oxidative and may be used up combating oxidative stress;[39] and
Zinc: some studies have found that individuals with PCOS have lower zinc levels but more research is needed.[40]
There are a variety of different diets which are based on increasing intake of vitamins and minerals (and often reducing animal fats and processed foods); these include:
5 4 3 2 1 Campaign: health-focused initiative (not a specific diet) promoting vegetables (5 per day), fruits (4), proteins (3), sauces or spreads (2) and grain (1);[41]
Mediterranean and Mediterranean-Low-Carb Diet: as above;
Dietary Approaches to Stop Hypertension (DASH) Diet: healthy-eating plan focused on preventing or treating hypertension (high blood pressure), high in vegetables, fruits and whole grains and limiting foods that are high in sodium (salt);[42]
Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) Diet: combination of Mediterranean and DASH diets;[43]
Pescatarian Diet: eliminates food that comes from the flesh of land-based animals but continuing to eat fish and seafood (as well as typically dairy and eggs);[44]
Lacto-Ovo Vegetarian Diet: eliminates food that comes from the flesh of animals but not dairy products or eggs);[45]
Lacto-Vegetarian Diet: eliminates food that comes from the flesh of animals, eggs and foods that contain them (but not dairy products);[46]
Ovo-Vegetarian Diet: eliminates food that comes from the flesh of animals, dairy products and foods that contain them (but not eggs);[47]
Vegetarian Diet: eliminates food that comes from the flesh of animals;[48]
Vegan Diet: based on consuming plant-based foods and eliminating any foods that come from animals, including dairy and eggs;[49] and
Daily Dozen Diet: whole-food plant-based based on research of Dr. Michael Greger.[50]
Alternatively, individuals may choose to include dietary components to increase intake of specific vitamins and minerals, for example:
Vitamin B6: chickpeas, beef liver, yellowfin tuna, sockeye salmon and/or chicken breast;[51]
Vitamin B9 (folic acid): beef liver, spinach, black-eyed peas, fortified cereals and/or white rice;[52]
Vitamin B12: beef liver, clams, oysters, nutritional yeast, salmon, tuna and beef;[53]
Vitamin C: red peppers, oranges/orange juice, grapefruit juice, kiwis and green peppers;[54]
Vitamin D: fatty fish such as trout, salmon, tuna and mackerel;[55]
Magnesium: pumpkin seeds, chia seeds, almonds, spinach, cashews and peanuts;[56]
Selenium: Brazil nuts;[57] and
Zinc: oysters, beef, blue crab and fortified cereals.[58]
Before making changes to your diet, it is recommended that you consult a healthcare professional, especially if you have health conditions or are taking medication, to ensure the new diet is safe and appropriate for you.
Sources
[1] https://www.ers.usda.gov/data-products/chart-gallery/chart-detail?chartId=58376
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC10302286/
[3] https://www.britannica.com/science/food-pyramid
[4] https://www.britannica.com/science/food-pyramid
[5] https://www.cancer.org/cancer/latest-news/5-small-diet-changes-that-can-have-a-big-impact.html
[6] https://pmc.ncbi.nlm.nih.gov/articles/PMC8643565/
[7] https://www.sciencedirect.com/science/article/pii/S240585722300116X
[8] https://www.obgproject.com/2019/06/12/pcos-part-1-sensitive-care-of-the-pcos-patient/
[9] https://pmc.ncbi.nlm.nih.gov/articles/PMC3277302/
[10] https://pubmed.ncbi.nlm.nih.gov/23315061/
[11] https://www.sciencedirect.com/science/article/pii/S0015028206000987
[12] https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/carbohydrates
[13] https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
[14] https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
[15] https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/carbohydrates
[16] https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
[17] https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance
[18] https://my.clevelandclinic.org/health/articles/16037-mediterranean-diet
[19] https://www.eatingwell.com/article/7669444/low-carb-mediterranean-diet-plan/
[20] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://tim.blog/wp-content/uploads/2019/07/tim_ferriss_the-4-hour-chef_one_pager_slow_carb_diet.pdf
[21] https://www.cancer.gov/about-cancer/treatment/side-effects/nutrition/high-fiber-foods
[22] https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-023-07569-6
[23] https://www.ncbi.nlm.nih.gov/books/NBK537084/
[24] https://www.ncbi.nlm.nih.gov/books/NBK537084/
[25] https://pmc.ncbi.nlm.nih.gov/articles/PMC7103851/
[26] https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-023-07569-6
[27] https://www.healthline.com/nutrition/ketogenic-diet-101
[28] https://health.clevelandclinic.org/what-is-the-atkins-diet-and-is-it-healthy
[29] https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/south-beach-diet/art-20048491
[30] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/paleo-diet/art-20111182
[31] https://whole30.com/
[32] https://www.dukandiet.com/low-carb-diet/4-phases
[33] https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2024.1393847/full
[34] https://mcpress.mayoclinic.org/dairy-health/chronic-inflammation-what-it-is-why-its-bad-and-how-you-can-reduce-it/
[35] https://www.sciencedirect.com/science/article/pii/S0960076019306211
[36] https://www.sciencedirect.com/science/article/abs/pii/S0960076016302199
[37] https://pmc.ncbi.nlm.nih.gov/articles/PMC5175507/
[38] https://www.verywellhealth.com/pcos-and-magnesium-4145000#citation-3
[39] https://pmc.ncbi.nlm.nih.gov/articles/PMC9901141/
[40] https://www.sciencedirect.com/science/article/abs/pii/S0946672X18306734
[41] https://www.sciencedirect.com/science/article/abs/pii/S1499404606006075
[42] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/dash-diet/art-20048456
[43] https://www.heartandstroke.ca/articles/eat-to-protect-your-brain
[44] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/vegetarian-diet/art-20046446
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[49] https://www.nhs.uk/live-well/eat-well/how-to-eat-a-balanced-diet/the-vegan-diet/
[50] https://nutritionfacts.org/
[51] https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/
[52] https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
[53] https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
[54] https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
[55] https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
[56] https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
[57] https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
[58] https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/
Causes - Diet