Are Interstitial Cystitis and Leaky Gut Connected?

Are Interstitial Cystitis and Leaky Gut Connected?

Please remember that I am not a doctor. The information in this post is for entertainment purposes only and is not intended to constitute medical advice. Always consult with a qualified health professional before implementing any dietary or lifestyle changes.

I firmly believe that there is significant overlap between ‘leaky gut’ and interstitial cystitis. I have mentioned it in several blog posts, so I thought it was high time I dedicated a whole post to the topic!

Whenever I speak to people about interstitial cystitis, I almost always urge them to Google leaky gut. Often, they will tell me that it’s funny I should mention that, because they have irritable bowel syndrome, or suffer from constipation, or can’t eat wheat… Their digestive symptoms invariably precede their bladder issues, which leads me to think that the former may be a causal factor in the latter. Did you know, though, that it is quite possible to have gut issues and not actually have any digestive symptoms? Admittedly some sort of bloating, wind, diarrhoea, constipation or digestive discomfort is usually present, but it doesn’t have to be the case. If you have ANY kind of chronic health issue that doesn’t have some other definitive cause, I would suggest that optimising your gut health should be a crucial part of managing your condition.

How Digestion and Absorption Work

  • When you eat, digestion begins in the mouth. Salivary amylase is mixed with your food as you chew and it begins to break down carbohydrates. This is one of the reasons why it is important to chew your food thoroughly – if you gobble, you literally deny your body the chance to carry out stage one of the digestive process properly.
  • After you swallow, your food is squeezed down your oesophagus and released into your stomach. In the stomach, it is churned about in a highly acidic environment to break it down further and kill harmful pathogens. An enzyme called pepsin is produced in the stomach lining. Its job is to break down protein into smaller amino acids. Contrary to popular belief, indigestion is not usually caused by an excess of stomach acid. Excess stomach acid is actually comparatively rare. Far more common is a deficiency of stomach acid. Inadequate levels of stomach acid and/or pepsin allow food that has not been sufficiently broken down to enter the small intestine, which can cause digestive discomfort and may itself be a factor in the development of leaky gut, gut dysbiosis and food sensitivities.
  • Once the stomach has done its work, it opens a sphincter which allows your now partially digested food to enter the first section of the small intestine. The pancreas squirts more enzymes into the small intestine, so that proteins, fats and carbohydrates can be further broken down. Bile from the liver is also released to emulsify fats. If insufficient pancreatic enzymes are produced, this too can lead to digestive discomfort, leaky gut, gut dysbiosis and food sensitivities.
  • The second and third stages of the small intestine are where the majority of absorption occurs. Here, an extremely thin layer of epithelium (the type of tissue that covers all body surfaces) allows the now digested nutrients to pass from the gut into the bloodstream. Any larger food particles, harmful substances or waste material remain in the gut and are passed along to the large intestine.
  • In the large intestine, water is absorbed, transforming liquid waste into solid faecal matter. Electrolytes are also absorbed and vitamins are produced and absorbed. The faecal matter is propelled along to the rectum.
  • Once in the rectum, the faecal matter stimulates nerves that give you the urge to defecate. At an appropriate time, you may choose to empty your bowels, whereupon the faecal matter passes through a sphincter from the rectum to the anus and out of the body.

What Is Leaky Gut?

In a healthy small intestine, tiny molecules of nutrients are allowed to pass into the bloodstream so they can be carried to wherever they are needed. Larger molecules and pathogens are denied access. This process is regulated by tight junction proteins, which form a selective seal between the epithelium (the think covering of tissue) and the endothelium (what lies beneath). They possess receptors that can be opened by certain small molecules, but which remain closed to bigger molecules or harmful invaders. They’re a little like nightclub bouncers on VIP night – if your name is on the guest list and you bring identification, you have the key to get inside, but if you’re not on the list or you bring the wrong identification, it’s access denied. Leaky gut – more properly known as ‘increased intestinal permeability’ – occurs when the tight junctions ‘slacken’ and start allowing harmful molecules to pass into the blood.

What causes leaky gut?

A number of factors can cause the tight protein junctions to ‘slacken’, including:

  • Stress
  • Non-steroidal anti-inflammatories (NSAIDs)
  • Alcohol
  • Smoking
  • Small intestinal bacterial overgrowth (SIBO)
  • Gut dysbiosis
  • Refined sugar
  • Processed foods
  • Intestinal infections or inflammation
  • Antibiotics
  • Pancreatic insufficiency

What are the effects of leaky gut?

Leaky gut may be caused or associated with a plethora of chronic health conditions including:

  • Diarrhoea-predominant irritable bowel syndrome (I experienced this for many years without knowing why.)
  • Ulcerative colitis
  • Crohn’s disease
  • Coeliac disease
  • Food intolerances (see this blog for an explanation of why this is and what you can do about it)
  • Arthritis
  • Eczema
  • Chronic heart failure
  • Anxiety and panic attacks (I suffered badly from these for many years, again without knowing why)
  • Depression
  • Headaches, brain fog and memory loss
  • A worsening in symptoms of autism
  • ADHD
  • Chronic fatigue
  • Autoimmune diseases such as type I diabetes, multiple sclerosis, and lupus

How can leaky gut be linked to so many different conditions?

Once larger molecules and pathogens start to be allowed access through the intestinal wall and into the blood, they are free to travel all over the place. In my blog about IgG food intolerance, I wrote the following:

IgG intolerances occur when IgG antibodies bind with a protein jacket via its antigen logo and form an immune complex. This immune complex triggers further immune responses, which are usually inflammatory in nature. This occurs especially when the body is not able to clear them as quickly as they are formed, enabling them to embed in body tissues and provoke an inflammatory response… It is important to note that it is the slow clearance of the immune complexes and not actually the IgG antibodies themselves that result in the symptoms you may experience… IgG food intolerances provoke inflammatory reactions in the body and these can occur anywhere in the body or brain. So if you suffer from chronic bladder pain or other pelvic pain that just doesn’t seem to abate no matter what you try, you should definitely consider the possibility that you have IgG food intolerances.

The same principle applies to any harmful molecules that are granted access to the blood really. They can trigger inflammatory reactions that can manifest themselves in a wide range of symptoms. Why do some people get eczema, some get migraines and some get anxiety? Who knows? Perhaps it depends what exactly is getting through. Perhaps we each have a system that is our Achilles heel and that is where symptoms manifest first. The truth is we don’t really know. What we do know is that epithelial tight junctions are found not only in the small intestine, but also in the lungs, the brain, the kidneys – all organs in fact. And that they too can become slack and leaky.

How is leaky gut relevant to interstitial cystitis?

I believe there are two ways in which leaky gut may contribute to interstitial cystitis. And please remember the disclaimer above – this is only my opinion. Firstly, if leaky gut can lead to food intolerances that can provoke inflammatory responses, and can also in its own right promote inflammatory responses, it stands to reason that the bladder could be just as affected as any other organ. I think most people with interstitial cystitis would agree that ‘inflammation’ is a very appropriate way to describe the sensations. Furthermore, some experts now believe that interstitial cystitis is an autoimmune condition and it is known that leaky gut is linked to various autoimmune disorders.

Secondly, let us think about how the urinary system actually works. Essentially, the kidneys act as filters for the blood. Blood passes through filtering units in the kidneys called nephrons; any waste products from the blood pass through the nephrons, into renal tubules and down the ureters into the bladder. The waste comprises urea, water and other waste substances – it is this mixture that we refer to as urine. Urea is produced when proteins are broken down in the body – it is what’s left over when your body has done what it needs to with the nutrients absorbed by the small intestine. Urine gathers in the bladder and is stored there until there is enough to stimulate the nerves that let you know you need to urinate.

Obviously, our urine spends a lot of time in contact with our bladder wall. IC sufferers will know all too well how strongly acidic (or strongly alkaline for that matter) urine can burn. They may also be aware that eating or drinking certain things has a fairly immediate effect on their pain levels. If the tight junction of the small intestine allows harmful molecules to pass through, a portion of these may be filtered out of the blood by the nephrons and sent to the bladder. Here they can sit for a few hours, potentially aggravating your bladder wall, which also has tight junctions. These may themselves slacken, so around and around we go.

This is why I believe it is so critical that interstitial cystitis sufferers see their gut health as being as much a priority as their bladder health. In my opinion, they are so interlinked that they cannot be viewed separately.

What should you do about leaky gut?

There are whole books, websites and articles devoted to this topic, so I cannot possibly cover it in detail here. However, I will describe some of the things I did myself and consider to be essential.

I started taking antifungals to address overgrowths of candida and harmful bacteria. I had been eating a typical Western diet high in sugary foods, gluten and dairy products for years. I used to occasionally drink alcohol. I had been under a lot of stress. I had taken antibiotics several times in my childhood and early adulthood. All of these things create ideal circumstances for killing beneficial bacteria, allowing pathogens to proliferate, and sowing the seeds for increased intestinal permeability. I took a mixture of antifungals every day for several months. For a while, you can get bloating, wind, and digestive discomfort. This is known as a ‘die off’ reaction. It is not a sign that the antifungals disagree with you, but rather that they are doing their job.  You can read more about antifungals and die off in this blog post

There are plenty of antifungals to choose from, but popular options are:

  • Oregano oil (Sweet Cures do a clean, high-quality one in a convenient softgel which eliminates the burning experienced with using liquid oregano oil products)
  • Caprylic acid
  • Grapefruitseed extract (I used Citricidal by Higher Nature, although I now realise this has ascorbic acid in. To be fair, it can’t have very much as I am highly sensitive to even small amounts of ascorbic acid and I was fine with it. I’m sure there are other brands that don’t have any in.)
  • Garlic (NOT odourless supplements – some of the goodness is in the smelly bit!)
  • Pau D’Arco (I use Rio Amazon capsules)
  • Ginger
  • Berberine
  • Hydrastis Canadensis
  • Aloe vera (good news if you are taking a high-potency aloe vera capsule or powder already! Bad news is that aloe vera is a fairly mild antifungal, so in my opinion you’ll need to add something with more clout as well.)

I started taking things to heal the gut wall itself. By some margin, I consider L-glutamine to be the most crucial ingredient here. Within days of taking L-glutamine three times a day, the horrible raw feeling that had been in my tummy for years subsided and I started to have normal bowel movements. I haven’t used L-glutamine continually over the last decade, but I do make sure to have sustained periods of time back on it on a regular basis. I’ve been taking it twice daily for the last few months and don’t plan to come off it anytime soon. I think powder is far superior to capsules and I use the Lamberts brand. Other things you might wish to incorporate are N-acetylcysteine (NAC) slippery elm, aloe vera (again!), quercetin, zinc and bone broths.

I strictly eliminated gluten, wheat, dairy, alcohol and sugary foods for three months. I then spent a few years trying to sneak them back in, but my body won’t have any of it. In my opinion, this step must be adhered to – I know it’s difficult, but you simply can’t expect your digestive tract to heal if you continue to damage it weekly or even daily. (See my post Would You Be Kinder to Your Bladder and Bowels If You Could See Them.) I would recommend that everyone spend at least three months off these food groups during their gut healing protocol, not only to give your digestive tract chance to repair, but also to learn new cooking and eating habits so that you will be able to sustain a healthier way of eating in the long term. If you can afford to, I’d highly recommend taking a FoodPrint test by Cambridge Nutritional Sciences. Chances are if you have leaky gut, you also have food intolerance issues. The tests are an investment, but will save you time and money in the long run, as they remove much of the guesswork from your healing journey. I was hugely impressed with Cambridge Nutritional Sciences when I used them for a FoodPrint200+ test a few months ago and I wish I had discovered them years ago!

I started taking probiotics. If you’ve got leaky gut, you won’t have too many good bacteria knocking around in your digestive tract anyway. The antifungals you’ll need to take will not discriminate and they’ll take some good guys out with the bad ones. Also, if you have interstitial cystitis, you’ll likely have spent a lot of time on antibiotics, which will also have wiped out much of your gut microbiota. It’s an essential part of the gut healing process to replenish the good bacteria. As well as taking probiotic supplements, you could also eat raw unpasteurised sauerkraut and kimchi, and drink raw unpasteurised kombucha or jun. I do not recommend fermented dairy products unless you are sure that you are able to tolerate all components of dairy – lactose free is no good to those with casein intolerance!


The digestive tract plays a pivotal role in our overall health and it is imperative that we take care of it. In my opinion, anyone with any kind of chronic health issue that cannot be directly attributed to another cause should consider their gut health and take steps to optimise it. This is difficult to do, because it requires us to make many dietary sacrifices in the short term and changes in the long term. However much we might wish it were different, there is no escaping this. It takes discipline, organisation and willpower. It may also involve a significant financial outlay in terms of supplements and ingredients to begin with. And it takes time. Various internet programmes promise to rid you of leaky gut, candida, etc. within two weeks – these are false promises.

In reality, while you may notice some improvements within days, it takes several months to properly restore gut health. In relation to interstitial cystitis, it takes six weeks for all layers of the bladder to regenerate, so try to think in blocks of this length when monitoring your progress. Any supplements you need should be easily available online or from health food shops. Beware of proprietary blends from unscrupulous websites that require you to pay a membership fee, do not list their ingredients, or force you to buy packages. Finally, don’t expect to get everything right first time. Nobody knows everything when they first start out. I made so many mistakes on my own gut healing journey and it was YEARS before I stopped ‘falling off the wagon’. Also, as our bodies change, our nutritional needs change; however, we might not realise straight away, meaning we can continue to make mistakes even when we think we are doing the right thing!

I hope that in sharing this blog with you, I will save you from making a few of the mistakes that I made and will put you on a more direct path to good gut health. I hope that some of you with interstitial cystitis will consider addressing your gut health and will see improvements in your symptoms as a result!

Wishing you the best of health,


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