Why Prebiotics are Important for PCOS and Where to Find Them


I usually recommend that most of my patients with PCOS eat a moderately low carb, low glycemic diet. Some women take their carbs even lower by following a very low carb diet, and others go as low as to be on a ketogenic diet. The outcome – your diet ends up being low in an “overlooked” nutrient that is essential for good health. This blog post is lengthy and a little “sciencey” … but try to read it! This is an important topic for women with PCOS as gut health may play a role in treating PCOS. The nutrient I will be discussing plays a role in lowering insulin levels, body weight, body fat percentage, appetite, blood cholesterol and blood glucose.

You’re probably familiar with the health benefits of probiotics and may even be taking a probiotic supplement. Research has shown that probiotics (“good bacteria”) play a major role in our health – including improved immunity, digestive health, mental health, weight control, decreased risk of diabetes, heart disease, and more. But I bet you haven’t heard much about prebiotics. These non-digestible carbohydrates are essential to help “feed” your good bacteria. And most of us don’t consume nearly enough of them as we consume less than 50% of the recommendations for fiber each day. And even if you have a high fiber diet, I bet it’s not high in prebiotic fiber!

Think about what happens if you don’t water your garden. It dies. The same goes for probiotics. They are living organisms in your gut that need food in order to survive. Prebiotics are natural, non-digestible ingredients that stimulate the growth and/or activity of healthy bacteria in the colon. Envision them as fertilizers for watering the “garden” of good bacteria inside your body. If you don’t consume adequate prebiotics, the probiotics can’t function optimally.

In addition, studies have demonstrated that prebiotics on their own play an important role in weight management, and lowering blood sugar, insulin levels and cholesterol. Read on to learn more about prebiotics, where to find them and the health benefits.

internal organsQuick low down on gut health & microbiome

We all have about 5 pounds of bacteria living in and on us; the majority is in our intestinal tract. Our microbiome (gut bacteria) regulates our overall health, immune system, metabolism, energy, body weight, mood, food choices, nervous system, heart health, risk of diabetes, metabolic syndrome, osteoporosis, mental health, allergies, etc. A healthy gut is one that contains a good balance of bacteria as well as diversity. It’s believed that modern lifestyles and the Western diet (high in fat, sugar and processed foods and low in fiber) – play a role in the reduction of good bacteria and overall diversity. Foods high in fiber, especially certain types of fiber and resistant starches called prebiotics, play a major role in keeping our gut bacteria in balance. *Studies are suggesting women with PCOS have an altered gut microbiome, so getting it back in balance is important!

Fiber and prebiotics

Most of us think of fiber as roughage that helps keep you regular! While fiber may help prevent constipation, there are many different types of fiber that have a wide variety of functions in the body. Fiber can be classified as insoluble, soluble and resistant starch. It’s broken down further into dietary, viscous and fermentable fiber. I don’t want to get into a science class here, so for those who want to learn more, check out my references below. The article focuses mainly on prebiotic fibers because of the key role they play in overall health. Keep in mind that while all fiber has health benefits, not all fiber is considered a prebiotic.

Prebiotics are a type of non-digestible fiber compound. Because they can’t be digested, they pass through the upper part of the gastrointestinal tract and remain undigested. Once they pass through the small intestine, they reach the colon, where they’re fermented by the gut bacteria. Here’s where the good things happen! The gut bacteria ferments soluble fiber, releasing metabolites such as SCFA including butyrate, acetate and propionate acids. These short chain fatty acids provide metabolic benefits discussed below. Prebiotic fibers provide additional benefits by maintaining balance and diversity of intestinal bacteria, especially increasing the presence of “good bacteria” called lactobacilli and bifidobacteria.

In order to classify a food ingredient as a prebiotic, it requires scientific demonstration that the ingredient:
-Resists gastric acidity, hydrolysis by mammalian enzymes, and absorption in the upper gastrointestinal tract
-Is fermented by the intestinal microflora
-Selectively stimulates the growth and/or activity of intestinal bacteria potentially associated with health and well-being.

Types of prebiotics: (excerpt from Travelling Dietitian blog)

Within both prebiotic fibres and resistant starches, there are sub-divisions;
The prebiotic fibre subdivisions include (but are not limited to):
-Oligosaccharides i.e. fructo-oligosaccharides, iso-molto- oligosaccharides, xylo-oligosacharides and galacto-oligosacharides
-Gums and mucilages i.e guar gum, acacia gum, psyllium
-Fruit and vegetable fibres  i.e lupin kernel fibre and legume fibre
-Other non starch polysaccharides i.e pectin (in apples), beta-glucan (in oats and barley) and hemicellulose (glucomannan inside konjac root)

Health benefits of prebiotics

I’ve watched several webinars in the past few weeks on the microbiome and prebiotics and you can be sure I’ll be encouraging my patients to consume more of them! Here are some of the benefits:

  1. Aid in weight loss by reduced energy intake and appetite, decreasing BMI and body fat%
  2. Play a role in bone health by enhancing calcium and other mineral absorption
  3. Reduces fasting and postprandial glucose, as well as insulin levels
  4. Stimulation of neurochemical-producing bacteria in the gut
  5. inflammationReduces risk of heart disease by decreasing cholesterol and inflammation
  6. Reduces inflammation. Inflammation is linked to many diseases. pic credit
  7. Improves gut health and digestion. Research has shown that higher intakes of prebiotic foods can increase numerous probiotic microorganisms, including Lactobacillus rhamnosus GG, L. reuteri, bifidobacteria, and certain strains of L. casei or the L. acidophilus-group. Prebiotics, along with probiotics, can help treat many digestive problems, including: diarrhea (especially after taking antibiotics), certain intestinal infections and chronic disorders like Crohn’s disease and ulcerative colitis, symptoms of irritable bowel syndrome (IBS)

NOTE: Many people experience gas and bloating when increasing intake of prebiotics – especially if you have a pre-existing gastrointestinal problem. So ease into them slowly. Some people with gastro-intestinal problems should not increase this type of fiber, so check with your doctor! Lastly, some people who have IBS are intolerant to these fibers due to worsened gas and bloating. But most of us should be able to tolerate small amounts and increase as tolerated!

Sources of prebiotics

You can get prebiotics from a variety of foods. They are also added to many foods like energy bars, and other high fiber products. You can also get prebiotic supplements.

Prebiotic rich foods (when possible, eat these foods raw to preserve more of the fiber content)
-Jerusalem artichokes
-Onions, chicory, garlic, leeks
Fruit such as under-ripe bananas, cherries, berries, apples
-Cruciferous vegetables including broccoli, cauliflower, collards, bok choy, Brussels sprouts, mustard greens and kale
-Other vegetables including mushrooms, asparagus, eggplant, radishes
-Burdock root
-Konjac root or glucomannan
-Yakon root
-Sea vegetables like seaweed, spirulina and other marine algae
-Chinese chives
-Green tea
-Lupin beans and lupin flour
-Green banana flour (resistant starch)
-Potato starch (resistant starch) and cooked cooled potatoe

Prebiotic products (these may be added to food products. Read labels)
-Acacia powder and gums – one of the richest sources of prebiotics in a natural food supplement powder
-Chicory root fiber found in many high fiber or low sugar products (e.g no added sugar ice-creams, or energy bars)
-Isomolto-oligosacharides (found inside food products)
-Inulin (added to many high fiber food products like energy bars
-Wheat dextrin
-Prebiotic supplement (i.e. Prebiotin prebiotic fiber supplement  -100% natural Oligofructose Enriched Inulin)


Bottom line:

Our diet plays a major role in the types, amount and diversity of gut bacteria we have. The standard American diet is too low in overall fiber, including prebiotics. Prebiotics work together with probiotics to maintain the balance and diversity of intestional bactria especially preserving the “good bacteria”. Without adequate prebiotics, the little probiotic critters will die! So do your best to increase your intake of prebiotics. But remember to go slow – as increasing fiber intake, especially fermentable fiber found in prebiotics, can cause gas and bloating. Reminder: if you have any gastrointestinal conditions, please check with your doctor before increasing your intake of fiber!

Stay tuned for a blog post on probiotic rich foods



1. The Mighty Microbiome: What do we know and what do we need to learn? By Hannah Holscher, PhD, RD and Megan Meyer, PhD   Academy of Nutrition & Dietetics Webinar

2. http://www.nutritionaltherapyconference.com/wp-content/uploads/2015/09/MIcrobiome-FINAL.pdf

3. Traveling Dietitian has several excellent blog posts on prebiotics:
-Why prebiotics are the most important nutrient to boost your mood and prevent depression 
-Best prebiotic food list 

4. http://www.eatright.org/resource/food/vitamins-and-supplements/nutrient-rich-foods/prebiotics-and-probiotics-the-dynamic-duo

5. High-Fiber Foods and Digestive Health: More or Less

6. Dr. Axe: Prebiotics

7. Healthline.com: 19 best probiotic foods 




I especially love problem-solving, whether it’s helping women defeat issues plaguing them for years, helping a busy executive find practical ways to get heart healthy, or providing tips to help you reverse diabetes. That’s why I’m on a constant quest to expand my knowledge by staying on top of the latest research.

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