Over recent years a lot of attention has been given to the relationship between gut health and our overall wellness. It goes without saying that any condition affecting our digestive system might adversely affect our general feeling of well-being, but is it possible that this could be the route of a variety of long term conditions such as multiple sclerosis, chronic fatigue syndrome or even hay-fever?
Well, according to proponents of a gastrointestinal disorder commonly known as “leaky gut syndrome” there is a direct connection between your gut and a number of autoimmune diseases.
What is leaky gut syndrome?
Along with the lungs and skin, the gut (or intestinal tract) is our main interface with the outside world. As a consequence it is also home to the biggest compliment of immune defences in the body to keep out all the potentially harmful microscopic invaders. But, for the intestine to function it must also allow the essential nutrients from our food to cross this barrier and enter our bloodstream.
So far, so good. The lining of our guts needs to keep out the bad stuff and let through the good stuff. To a large extent this flow is controlled by the size of the gaps between the cells which line the intestine. These gaps can be controlled by structures known as tight junctions which join the cells together to allow the gut wall to become more or less permeable.
Whilst it is perfectly natural for the permeability of the gut to fluctuate there are a range of factors that can cause it to increase. This is known as intestinal permeability and may be the result of conditions such as Crohn’s or celiac disease, or it can be the result of medication like aspirin or a side-effect of chemotherapy.
When this increased permeability (or leaky gut) occurs, larger particles (although still microscopic) are able to cross from the gut to the bloodstream.
Leaky gut syndrome is actually the range of conditions and symptoms that are claimed to be caused by these larger particles crossing into the bloodstream. The theory is that this allows toxins, bacteria and undigested food particles to cross from the gut to your blood where they trigger the immune system which sees them as “foreign invaders”. It is this immune response that triggers the symptoms associated with leaky gut syndrome.
What are the symptoms of leaky gut syndrome?
The list of symptoms below are only those that have been associated with leaky gut syndrome, it is therefore not strictly accurate to call them symptoms. Instead they should be thought of a range of conditions that are associated with the syndrome.
It is important to stress that they are an extremely common range of conditions, and the fact is they may have an identifiable cause or remain unexplained. However, it is impossible to assume that the presence of one or more of these symptoms indicates leaky gut syndrome. In fact it may be the other way around – i.e. intestinal permeability is the result of one of the conditions.
Food allergies / intolerances, seasonal allergies and asthma
- Digestive issues
Bloating, cramps, gas, diarrhea or irritable bowel syndrome (IBS)
- Skin conditions
Acne, rosacea, scleroderma and eczema
- Autoimmune diseases
Celiac disease, lupus, rheumatoid arthritis and multiple sclerosis (MS)
- Psychological / mood disorders
Autism, anxiety, depression, ADD or ADHD
- Other symptoms
Tiredness and chronic fatigue syndrome, migraine, fibromyalgia
Studies have indicated that most of the above symptoms and conditions show some degree of correlation to increased gut permeability 1. This does not prove which is the cause and effect though, and some of the data from the studies is very borderline.
Leaky Gut – fact or fiction
There are two main camps when it comes to leaky gut syndrome; those who believe it is medical condition responsible for a host of symptoms, and those who feel there is insufficient (or no) evidence to suggest increased intestinal permeability causes these conditions. Those supporting the existence of leaky gut syndrome tend to be made up of nutritionists and practitioners of complementary and alternative medicine 2. On the other hand those who do not accept the theory are the majority of the medical establishment.
It is easy to say dismiss either side. You can argue that the medical world is slow to take on new ideas, however, I would say this is untrue if you look at the cutting edge progress being made in the fight against illnesses such as multiple sclerosis and cancer. The world of medicine operates on fact and this comes in the form of evidence from studies. To date there is a lack of quality research to support the concept of leaky gut syndrome as proposed by many of its supporters3.
Despite the fact that leaky gut may not be a recognised medical condition there are several facts that are supported by studies.
Fact: Leaky gut exists.
There is no arguing that increased intestinal permeability is real. Where the controversy lies is whether it the cause of the symptoms or is just a symptom of an underlying condition.
For example, Crohn’s disease can cause gut permeability to increase – it is not caused by having a leaky gut.
Fact: Gluten sensitivity can increase gut permeability.
Studies have shown that individuals who are gluten intolerant often show elevated intestinal permeability 4. This is linked to the protein Zonulin which can be activated by a glycoprotein found in wheat.
Fact: There is link between intestinal permeability and several health conditions
There have been quite a number of studies into the relationship between a number of diseases and gut permeability. Quite a few of these have shown extensive evidence that there is some sort of relationship. Among these are Crohn’s disease, type I diabetes and HIV. What these studies do not show is which is the cause and which the effect.
Fiction: There is hard evidence that the array of symptoms associated with leaky gut syndrome are caused by excessive intestinal permeability
To date there has been no conclusive proof that having a leaky gut is responsible for the wide range symptoms suggested. As mentioned above the current scientific thinking is that leaky gut is just a symptom of a range of other conditions, and not the cause.
Is leaky gut syndrome a myth?
Whilst it may be a little premature to dismiss the leaky gut hypothesis there is currently a lack of proof to support it. There has been some interesting research into the relationship of intestinal permeability and other conditions but nothing to support some of the claims being made.
Without this evidence nobody can say for sure that leaky gut is responsible for the range of illness suggested. Therefore to claim it was would be a move of faith, something that has no place in the world of medicine.
Unfortunately there are those who are happy to tell you that leaky gut syndrome is a fact and if you have symptoms x, y and z then that is the reason. This is made worse by the claims of some so-called experts who will happily put practically any condition imaginable down to having a leaky gut. Then again many of these “experts” are making a living from what is one of the fastest growing sectors of the food and nutrition industry. Next time you look at a website telling you the 10 signs you have leaky gut syndrome, check whether they are selling a diet plan or a supplement!
A major problem with leaky gut and many other current ideas on the fringes of the medical world is they all seem to be fighting over the same set of symptoms. And this set of symptoms are actually some of the the most common unexplained symptoms found throughout the population. There are many other so called “fad diagnoses” which can equally well explain the host of symptoms associated with leaky gut syndrome 5.
In summary, the leaky gut syndrome theory sounds great; it is scientific sounding and appears to offer an explanation for a myriad of otherwise unexplained ailments. Unfortunately, at the present time there is no compelling evidence that it does exist.
- Relationships between intestinal barrier function and selected diseases↩
- “Leaky gut syndrome” – NHS website↩
- Debunking the Myth of ‘Leaky Gut Syndrome’ – Canadian Gastrointestinal Society↩
- Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer↩