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About Your Digestive System

  • How the digestive system works
  • Bugs in the system
  • What happens when things go wrong?
  • How to help your digestive system
  • Digestive system and lifestyle

How the digestive system works
The main function of the digestive system is to take in and process food in order to provide the body with energy (calories) and nutrients. The gut also handles some substances made in the body such as cholesterol and bile salts, and provides an environment for the growth of ‘friendly’ bacteria needed for good health.

A healthy digestive system generally doesn’t cause problems, with the result that most of us don’t even think about what’s happening to our insides. We may sometimes hear bubbling, gurgling sounds or wind coming up (belching) or going down (flatulence). But in fact, these are only tiny parts of the constant conversation that our digestive system has with other parts of our body, particularly our brain.

Our digestive system is a bit like a miniature factory. Basic materials go in at one end…they’re processed…the flow rate is controlled…products are created and diverted to one side…other things are added… yet more products are diverted to the side… and finally a residue passes out at the end.

The digestive system is made up of a complex series of organs: the mouth; the gullet (oesophagus; the stomach; the small and large intestines; the pancreas; the liver and the gall bladder. Your FREE copy of The Inside Out Diet will give you the full low-down.

Bugs in the system
Believe it or not, there are more bacteria in your colon than there are humans on this planet! And just as on this planet, there’s competition for space to live. Just as local conditions affect people’s preferences for somewhere to live, the local conditions of the large intestine determine the types of bacteria that will grow. Like people, bacteria directly affect their environment: while some bacteria have minimal effect, ‘harmful’ bacteria may damage their environment and increase the risk of infection, whereas ‘good’ bacteria (such as those found in Yakult) help keep the environment healthy, often improving digestion and making certain vitamins. The key is to get the right balance of ‘good’ and ‘bad’ bacteria in the large intestine.

What happens when things go wrong?
The digestive system can go wrong in many different ways, but it usually sends out some signals to tell you things aren’t right. Abdominal pain, changes in bowel habit, nausea or vomiting are all tell-tale signs that something is wrong. You should see your practice nurse or doctor for advice if…

  • Your bowel habit has changed within the last two to three months and you've not changed your diet, been travelling or started taking medication
  • You've seen blood in your stools – new red blood, or black stools containing digested blood
  • You have persistent, unexplained abdominal pain or discomfort
  • You have lost 2kg (4lb) in weight recently for no obvious reason
  • You have lost your appetite and/or frequently feel sick for no obvious reason
  • You are frequently constipated and simple treatments such as a high-fibre diet, more fluids, more exercise and over-the-counter laxatives haven’t worked
  • You frequently open your bowels more than three times a day or if your stools are often loose or watery
  • You frequently get a lot of unexplained wind, bloating or abdominal distension

How to help your digestive system
Your FREE copy of The Inside Out Diet contains in-depth information on helping your digestive system to stay healthy, but here’s a few key pointers to get you started:

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Healthy diet
Unsurprisingly, eating a healthy, balanced diet is the easiest way to help keep our digestive system – and every other part of our body – in tip top shape. Ultimately, we should eat more fruit, vegetables, starchy, fibre-rich foods and fresh products, and fewer fatty, sugary, salty and processed foods.

Boost those friendly bacteria – Probiotics
Probiotics are live bacteria that improve the balance of good and bad bacteria in the gut. The most common probiotic bacteria are bifidobacteria and lactobacilli – found in products like Yakult. Probiotic bacteria survive the acidic conditions of the stomach and pass into the small and large intestines alive. Once there, these good bacteria compete for the limited space in the gut and in doing so, help to control levels of harmful bacteria. For more information on probiotics, visit

Feed those healthy bacteria - Prebiotics
Prebiotics are foods which help to stimulate the growth of good bacteria in the gut. Good sources of prebiotics include many carbohydrates made from the sugar fructose. These types of carbohydrates occur in the Allium group of plants (onions, garlic, shallots, leeks), and in asparagus, chicory and artichokes, as well as to a lesser extent in beans and pulses (such as chickpeas and lentils) and some cereals, e.g. oats

Fill up on Fibre
There are two main types of fibre: insoluble and soluble fibre, both with their individual benefits to the digestive system. Foods that contain insoluble fibre (eg wholegrain cereals) can act as a laxative which helps prevent constipation, whilst large amounts of soluble fibre (eg oats, fruit, veg and pulses) can help reduce blood cholesterol levels and can also help people with diabetes control their blood glucose levels.

Healthy weight
Being overweight or obese affects all aspects of our health and also has an effect on our digestive system. Fat stored around the midriff can put pressure on the stomach – tending to squash food already mixed with stomach acid back up into the gullet. This can cause heartburn and, if left untreated, painful ulceration. Check out your BMI and find weight loss tips in The Inside Out Diet.

Digestive system and lifestyle
Our digestive systems can be affected by various aspects of modern lifestyles. The Inside Out Diet offers top tips on various aspects of lifestyle, including:

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Going on holiday or taking a trip abroad can play havoc with our digestive system. Long periods of inactivity on the plane or by the pool, changes in air cabin pressure, dehydration, and different eating and drinking habits, can all contribute to holiday bloating, constipation or diarrhoea. But by preparing your digestive system in the weeks before your holiday, you can minimise the chances of falling ill once you’re there.

As well as killing harmful bacteria, many antibiotics also kill beneficial bacteria that keep our digestive system healthy. In fact, when we take antibiotics, up to 60% of the total amount of bacteria in our gut – both good and bad – can be killed. The result can sometimes be diarrhoea.

Believe it or not, the amount of sleep we get can affect our bowel habits. Just like the rest of our body, our digestive system needs time to relax and recuperate. Going to bed and getting up at regular hours each day can help our digestive system work more effectively and improve the regularity of our bowel habits.

Drinking too much alcohol doesn’t just affect the liver. It’s toxic to every part of the body, including the brain, the pancreas, the muscles and even our digestive system. Alcohol is at its most concentrated in the stomach – especially when no food is present – and as a result, when consumed in large amounts can cause irritation and inflammation of the stomach lining. This in turn may result in nausea and vomiting.

Stress is a normal part of life in today’s modern society and small amounts may actually be good for us, helping us to perform more effectively. However, problems arise when our lives cause an abnormal amount of stress, and one of the first parts of the body to react to stress is our digestive system.

You’ve heard it hundreds of times before, but smoking is bad for your whole body, including your digestive system. Smoking is responsible for many changes in the digestive system. It contributes to common disorders such as heartburn and peptic ulcers. Smoking also increases the risk of Crohn’s disease and gallstones. Another reason to try and quit is that smoking decreases your liver’s ability to handle alcohol, so the two combined are double trouble for the digestive system.

Staying hydrated is essential to the health of your digestive system. The human body needs water to maintain enough blood and other fluids to function properly. As soon as the body begins to lose a substantial amount of water more quickly than it is replaced, the body starts to get dehydrated. A common effect of dehydration on your digestive system is constipation.

Getting Older
Ageing not only affects the way we look on the outside. As we get older, the bacteria living in our gut also change, tipping more in favour of harmful bacteria. Levels of beneficial bacteria may drop and as we get older our immune systems become weaker. As 80% of the immune system is gut-associated it is important that the gut’s beneficial bacteria are maintained to support it.

For top tips on managing your lifestyle in order to keep your digestive system healthy, order your FREE copy of The Inside Out Diet now