pcos and gut health

Is Your Gut Bacteria The Secret To Your PCOS Weight Loss?


When it comes to discussing PCOS and gut health to my clients, I get some pretty interesting responses. Whenever I suggest that their gut bacteria (or yeast and other pathogens) might be the key to their weight loss, I’m often met with disbelief. The two things can’t be connected, can they? Weight loss is just about calories in and calories out, right?

Well, no. The gut is one of the most ignored organs of the body. We’ve only recently started to see studies linking dysregulated gut flora with a range of diseases and conditions. These range from obesity, diabetes, autism, and depression, to autoimmune diseases like Type 1 diabetes and Hashimoto’s thyroiditis. In fact, many experts believe that the study of gut bacteria in the 21st century will be what the study of antibiotics was in the 20th century.


PCOS and Gut Health: The Microbiome

The microbiome is the name given to the bacteria, viruses, fungi, and protozoa that live in your body. We have 100 trillion microorganisms in our bodies – found in the gut, nose, throat, skin, and urogenital tract – that’s 10 times the number of cells that we have!

The microbiome is responsible for many different functions in the body, including 75% of our immune system, as well as the digestion and absorption of our food. We often think of bacteria as being something that’s bad. In reality, it’s too much of the wrong type of bacteria, or not enough good bacteria, that’s the problem.

When it comes to PCOS, studies have shown that women with PCOS have less good bacteria and more bad bacteria than normal. In this article, I’ll be focusing on the gut microbiome and explaining what you can do to improve yours.


What Causes The Microbiome To Be Out Of Balance?

You can think of the microbiome as a community. Like any community, it has its good citizens and its undesirable ones. Problems arise when there are too many of the bad and not enough of the good. An unbalanced microbiome can be can be caused by many factors:

Having An Overweight Mother:
If your mother was overweight when you were born then you’re more likely to have a disrupted gut microbiome.

If You Were Born Via Caesarean Section:
The infant gut is virtually sterile in the mother’s womb. You inherit your microbiome from your mother’s vaginal tract, which you don’t pass through if you’re born via C-section. Babies born via C-section have significantly disrupted microbiomes.

Not Being Breastfed:
A fascinating study found that babies who were exclusively breastfed had the best microbiome. Babies who had a combination of breast milk and formula or were exclusively formula fed had similarly inferior microbiomes. This indicates that formula milk disrupts the microbiome.

Antibiotic Use, Especially In Childhood:
Broad spectrum antibiotics can negatively impact the microbiome for up to 2 years. If you were like me and had many bouts of tonsillitis or ear infections as a child then you’re unlucky in more ways than one.

The Contraceptive Pill and Anti-Inflammatory Drugs:
The contraceptive pill and anti-inflammatory drugs have both been found to negatively impact the microbiome.

A Low Resistant Starch Diet:
A diet low in resistant starch means that your bacteria starve, disrupting your microbiome.


PCOS and Gut Health: The Connection Between the Microbiome and PCOS

Women with PCOS have fewer good bacteria and more of the bad bacteria than normal. What’s less clear is whether a disrupted microbiome is the cause of, or is caused by, PCOS.

My personal opinion is that it’s a vicious cycle. If you have a disrupted microbiome then you are more likely to develop PCOS. The excess androgens in PCOS then cause the microbiome to become worse. Poor gut bacteria causes inflammation and insulin resistance. As inflammation contributes to PCOS, this supports the theory that poor gut bacteria is a contributor to PCOS.

Excess androgens also cause the microbiome to be out of balance, so PCOS definitely makes this worse. A common ‘treatment’ for PCOS is the contraceptive pill, which further disrupts the gut. The pill negatively impacts the gut microbiome and those taking it are at a greater risk of developing inflammatory gut conditions. Incidentally, the pill doesn’t really help with PCOS at all.


The Connection Between The Microbiome, PCOS and Weight Gain

The microbiome affects all of our PCOS symptoms, but the one I want to focus on in this post is weight gain. Studies have now shown that the microbiome directly impacts whether we become obese or not.

One study on mice found that mice that were missing a protein which keeps bad bacteria under control not only ate more, but also developed insulin resistance and obesity. When they transferred the gut bacteria from the obese mouse to the thin mouse then the thin mouse also developed Type 2 diabetes and obesity. This shows that Type 2 diabetes can be ‘transferred’ through gut flora.

Additionally, when they restricted the food of these mice, they lost weight but still had insulin resistance. The gut bacteria had damaged their metabolism. Another study found that mice with a disrupted microbiome experienced a 60% increase in body fat and insulin resistance in just 14 days, despite eating less.

There have since been many studies in humans (here, here, and here), which show that the gut microbiome differs between obese and non-obese people. So much for weight just being about calories in versus calories out.


How Does Too Much Bad Bacteria Contribute To Weight Gain and PCOS?

There is still much to be investigated in this area, but here are three mechanisms that we already know of:

Bad Bacteria Influences The Amount Of Calories We Absorb From Food

Too much bad bacteria increases the rate at which we absorb fatty acids and carbohydrates from food. It also increases the storage of calories as fat.

Bad Bacteria Makes Us More Insulin Resistant

The second mechanism that we know of relates to insulin resistance. Too much bad bacteria can cause an increased production of insulin.

Insulin is our storage hormone – it’s released when we eat and communicates to our cells to open up and take up blood glucose. When our cells become resistant to insulin, the communication doesn’t work so the glucose can’t get into our cells. This leads to the glucose being stored as fat instead. This is quite a significant mechanism in PCOS as 70% of women with PCOS have insulin resistance.

Bad Bacteria Makes Us Resistant To Leptin

Leptin is our ‘starvation’ hormone. Its main job is to regulate our fat storage and make sure that we have enough fat to survive the next famine (it hasn’t quite caught up with the constant availability of food yet). Leptin is excreted by our fat cells and acts on the hypothalamus, telling it whether we have enough fat or not. This then speeds up or slows down our metabolism accordingly. When this system is working well it means that we cannot gain more than a few pounds.

The problem is that just like our cells can become resistant to insulin, our hypothalamus can become resistant to leptin. Studies have shown that too much bad bacteria causes leptin resistance. When this happens then it can’t detect that there is any leptin in the blood. The results in our metabolism being slowed to conserve energy, which also increases our hunger levels.

Coincidentally, studies have shown that women with PCOS are significantly more likely to have leptin resistance. Now we just need some research to look at PCOS, leptin resistance, and the microbiome together (hint, hint, lab folks).


What Can You Do To Improve Your Gut Microbiome?

When it comes to PCOS and gut health, re-balancing your gut microbiome is an essential step in reversing your PCOS. This is especially the case if you have insulin resistance and want to lose weight. Repairing your microbiome can be complex for some. However, there are three things that everyone should do:

REMOVE: Foods and Drugs That Disrupt Your Microbiome

Antibiotics and anti-inflammatory drugs, such as ibuprofen, kill off beneficial bacteria. Although antibiotics are sometimes incredibly necessary, if you’re taking them for a condition like acne then you may be making your skin worse in the long run. Just one course of antibiotics can seriously disrupt the microbiome for up to a year.

Similarly, most of us don’t think twice about popping an ibuprofen for a headache or injury. However, these anti-inflammatory drugs can not only affect the microbiome, but also damage the lining of the intestinal wall. This can cause leaky gut and inflammation.

You should also remove all inflammatory foods from your diet. These are foods that you may be intolerant to (such as gluten and/or dairy) and foods that are inflammatory due to the way they are processed (such as high fructose corn syrup, seed oils and processed soy. You can find more information about this in my 5 Foods You Should Avoid if You Have PCOS article.

REPLACE: By Taking A Good Quality Probiotic and Eating Fermented Foods

The aim of re-balancing your gut microbiome is to increase the number of good bacteria and reduce the amount of bad. Probiotics reintroduce good bacteria into the digestive tract. A large study of PCOS women in 2015 showed that probiotics lowered blood sugar levels and reduced insulin resistance.

You can get probiotics into your system by taking a good quality probiotic supplement and/or eating fermented food. I would encourage you to introduce fermented foods, such as kombucha (fermented tea), water kefir, sauerkraut, and kimchi into every meal. Fermented foods significantly reduce the breakdown of carbohydrates, which reduces blood sugar levels.

FEED: The Good Bacteria By Eating Resistant Starch (Prebiotics).

Resistant starch is a prebiotic: a type of carbohydrate that feeds good bacteria and helps to increase it.

Think of your gut bacteria like a garden. The probiotics are the seeds and the prebiotics are the fertiliser, soil and food that helps to make them grow. You can put loads of seeds in a garden, but if you never feed them then they won’t grow. Your gut bacteria (probiotics) needs resistant starch (prebiotics) to grow.

Your gut bacteria live in the large intestine or colon. When we eat food, it passes through the stomach where it’s partially digested, then into the small intestine where all of the nutrients are extracted. Anything that can’t be digested passes through to the large intestine.

Resistant starch is resistant to digestion in the small intestine. Vegetables like potatoes, sweet potatoes, parsnips, beets, etc., as well as rice, all contain resistant starch. In their raw form, these foods contain resistant starch but don’t taste very nice. Cooking them improves the flavour but makes the starch digestible and not good for our bacteria. However, once these foods are cooled then the starch becomes resistant once again.

Resistant Starch and Insulin Resistance

Although resistant starch is a carb, it doesn’t get absorbed in our small intestine and cause a spike it blood glucose or insulin. Even better, we don’t absorb many calories from it either. In fact, studies have shown that resistant starch improves insulin sensitivity in people with insulin resistance.

But before you go and wolf down a ton of cold rice, remember to bear in mind that you may still absorb some carbohydrates from it. So keep to eating it in small amounts. As well as cold rice and cooked and cooled starchy vegetables, you can also find resistant starch in dehydrated green plantains or green bananas, and unmodified potato starch (you can add this to smoothies).

Some more blogs you might be interested in

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  1. Hi There,

    Amazing job summarising the latest research and keeping us all informed! Thanks so much :). Is there still any thought that there is a difference between ‘thin female PCOS’ and ‘overweight PCOS’? My Doctor downplays my PCOS symptoms as I’m not overweight. Thanks.

    1. Hi Elizabeth, in short, no not really, as weight is just a symptom, not a cause. Researchers now think that weight gain might be a way that the body tries to protect itself from damage.
      Instead, you need to be focussing on what’s causing your PCOS. One of the main causes is insulin resistance, but you can have insulin resistance and be lean. I’d recommend you read this blog next: https://thepcosnutritionist.com/resources/whats-causing-your-pcos/

  2. Hey Clare, I really appreciate your website. I’ve learnt a lot. Recently I went to the doctors. As a doctor specialised on the NHS in gynaecology, he should have done tests to see whether or not I have pcos, inulin resistant, thyroid (I told him there is a history in my family). He did not do this, in fact all he said to me was that he believed all my prom lems are related to my gut. Due to the fact that my GP said I have gut problems in my history.

    He said I dont have PCOS even though I have soooo many symptoms, insulin problems, possible thyroid, he believes it’s to do with my gut only. The only thing he did for me was prescribe me Yasmin birth pill. I don’t know whether to take it or not as I’ve never taken it. He says to me that even if I had PCOS, they would just give me the pill. It’s sad that instead of the NHS t stung you for allergies and intolerances, they just give the pill to mask things.

    3 months ago I decided for myself to change things. I cut out dairy, soya, gluten, sugar (apart from fructose from fruit) I’ve lost weight but I still have insulin problems, hair loss and hair growth so that’s probably why he gave me the pill. I don’t know what to do….any advise??

    If I could, I would definitely see you, especially as the last straw was fainting and being unwell for a month with extreme fatigue and breathlessness and other things.

    I’ve learnt more from you then I have with theses doctors so thank you again!!

    1. Hi Catia, Thank you, I’m really glad that this has helped. Your doctor is probably correct that your symptoms are related to your gut….the interesting thing is why he still gave you the pill. The pill does actually kill off good gut bacteria so will be making those issues worse. I would ask him his rationale for this.

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