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How your gut affects your overall health

We all know that when things aren't right with our digestion we can feel generally unwell. But evidence is mounting that the gut - which contains 70-80% of our immune tissue - could have an even greater impact on our overall health than once thought.

It's time to listen to our gut feelings.

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The impact of existing conditions

Those of us who suffer from diagnosed bowel conditions such as irritable bowel syndrome or inflammatory bowel disease will be well aware that these conditions can cause or exacerbate symptoms elsewhere in the body. But why is this?

"Your gut has two key functions," explains Dr Anton Emmanuel, consultant gastroenterologist at University College Hospital in London. "One is to absorb nutrients and the other is to secrete insoluble waste. When your gut is not working properly - for example, in the case of illnesses such as Crohn's disease or bowel disease - then the absorption can be impaired. As that's the door through which you get the nutrients to keep you healthy, those suffering from gut illnesses tend also to suffer from generalised body ill health.”

How your stomach affects your overall health

Could your bowel be causing problems?

Despite not having a diagnosed condition, many of us may wonder whether our skin conditions, poor immunity or even poor mental health might be linked to digestive health issues.

Theories abound about the link between poor digestion and our overall health and it is likely that there is a connection. The problem at present is that the necessary tests to confirm these theories have yet to be developed.

"Evidence is gradually accumulating as to the effect of an abnormal microbiome on health and disease," agrees Dr Adam Haycock, consultant gastroenterologist at The London Clinic.

"Unfortunately, we can't yet perform an accurate test, but from a symptom perspective there is very strong evidence to suggest that there's a link," explains Emmanuel. "It's much more likely that the testing we have is not as sophisticated as we'd like it to be rather than people are making things up."

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What is 'leaky gut' syndrome?

Some scientists believe that some illnesses may be caused by a condition known as 'leaky gut', where our bacterial defences have been breached, enabling toxins to leak from our bowel.

"The gut has a huge population of bacteria - 100 trillion," explains Emmanuel. "These are critical in terms of how your body and immune system work. They filter what goes into your body. If they are abnormal in some way it may allow substances into your body that shouldn't be let through."

Or is it a thing at all?

However, again, there is currently no conclusive test to confirm this condition in patients. What's more, many highly reputable gut experts remain to be convinced that there is any truth in the leaky gut theory.

For instance, the Canadian Society of Intestinal Research warns: "Many people are eager to believe that leaky gut syndrome is a valid illness because it seems like an answer to many of their health problems. When you really think about it, one diagnosis that explains arthritis, IBD, skin problems, fatigue, and more seems fictional. Even more unrealistic is that all of these symptoms will go away if the patient just takes a few supplements and avoids certain nutritious foods."

What about my mental health problem?

Those suffering from poor mental health frequently suffer from poor gut health; however, the extent to which the two different conditions affect each other is hard to ascertain. "We know that mental health problems can affect gut health - appetite and function," explains Emmanuel. "And this makes sense when we look at the strong connection between the brain and the gut. But this seems to work both ways - and it's hard to say whether a patient's gut problems are caused by poor mental health or vice versa."

Because of the problem between potential cause and effect, doctors tend to treat the problems individually.

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So, what does this all mean?

Whilst we may not have conclusive proof that certain conditions may be triggered or worsened by gut problems, it makes good sense to look after our gut microbiome. But unfortunately, this may not be as simple as choosing a prebiotic (prebiotics feed our bacteria) or probiotic (containing bacteria) and waiting for our health to flourish.

"There is pretty good evidence that probiotics and prebiotics are good for us and allow bacteria to colonise. There's good evidence in controlled trials that they can be very helpful in terms of gut symptoms and gut illnesses, but also even systemic conditions like psoriasis, rheumatoid arthritis and eczema," says Emmanuel.

However, whilst it makes sense to recharge these friendly bacteria, science still falls short of providing the right solution for each person. "The problem is that each person's gut bacteria are as individual as a fingerprint, so knowing which one you are short of and have too much of is difficult. Currently we don't have a test that says we have too much of X or Y and imbalance of Z. We have products that appear to work through randomised controlled trials and so we can confirm that they help people, but we can't yet tailor it to the individual," explains Emmanuel.

Finding the right formula

Whilst there are far more bacteria in the tablets or powders available from pharmacies than there are in yoghurts or yoghurt drinks widely advertised on TV, simply taking the highest dose of prebiotics and probiotics we can isn't necessarily the answer.

"If it was just a numbers game you were playing you'd tend to go for the capsules or the powder," says Emmanuel. "But it's all about the individual need. Some will do well with a yoghurt, some need a liquid or tablet version. It's a bit of a lottery and it's about getting the right ticket, so for you a small dose of the right product could be much more effective than a massive dose of the wrong one."

Despite the difficulty in establishing the correct treatment for each of us, it's certainly worth trying out different prebiotic and probiotic sources, as evidence suggests improving our bacterial population can help to improve symptoms.

As well as in specialist products, probiotics can be found in your kitchen too.

"Fermented foods are a rich source of probiotics - foods like kefir, sauerkraut, pickles, miso and tempeh," explains dietician Priya Tew. "There are also natural prebiotics in our diets - they are undigestible plant fibres. Some examples include Jerusalem artichokes, raw chicory root, raw onions, leeks and garlic, cooked onions, and bananas."

What else can I do?

In addition to improving our microbiome, Haycock suggests people should: "Drink enough liquid - at least two pints of water per day. Ensure you take a mix of soluble fibre, such as oat bran, barley, nuts, seeds, beans, lentils, peas, and insoluble fibre, which includes wheat bran, whole grains and vegetables," to help keep our digestive tract healthy.

He also recommends we: "Eat a variety of different-coloured fruits and vegetables; having more vegetables than fruit is preferable."

We should also try where possible to use the bathroom when we get the urge, rather than wait for a more opportune time, as holding on to our waste can make our digestive transit more sluggish.

Whilst it may not solve all our health issues, one thing is certain: looking after our digestion can only be a good thing.

Article history

The information on this page is peer reviewed by qualified clinicians.

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