Digestion and irritable bowel syndrome


You’ve probably heard the advice that eating healthier, exercising and relieving your stress, all facets of a healthy lifestyle, can help prevent disease.

But perhaps you haven’t really taken it to heart. The problem is that this knowledge doesn’t always translate into actions, and rather than starting an exercise programme or drinking a freshly prepared green vegetable juice, many of us do not take the important step to lifestyle changes.

This month I’m looking at the physical processes at work in the act of digestion, some possible causes of why your digestive system may become unbalanced, and what to do if it does become unbalanced. One of the outcomes of being unbalanced is irritable bowel syndrome.


A properly functioning digestive system is one of the steps to stop or avoid an irritable bowel. When your digestion improves so will your energy, immunity and general wellbeing.

The short definition of digestion – you put food or liquid into your mouth, swallow it, and your body breaks these molecules down into a size it can absorb. What your body doesn’t use is excreted as waste.

Your body receives help breaking down food from the organisms that live in your gut (intestinal flora). These bacteria, yeasts, and fungi can produce beneficial waste products as they feast on your digesting food, such as B and K vitamins which your body needs. They also function to break down some foods that your body cannot absorb by itself (they change carbs into simple sugars and proteins into the component amino acids).

But when you eat too many grains, sugars, and processed foods, these foods serve as fertiliser for the bad bacteria and yeast, which causes them to rapidly multiply. One of the best things you can do for your health, including your digestive health, is eliminate white refined sugars and processed foods as much as possible.

What is irritable bowel?

Irritable bowel syndrome (IBS) is a common disorder that affects the large intestine (colon). Irritable bowel syndrome commonly causes cramping, abdominal pain, bloating, gas, diarrhoea and constipation. It is a chronic condition that needs to be managed long-term.

Only a small number of people with IBS have severe signs and symptoms. Some people can control their symptoms by managing diet, lifestyle and stress.

The signs and symptoms can vary widely from person to person and often resemble those of other diseases. Among the most common are:

  • Abdominal pain or cramping
  • A bloated feeling
  • Gas
  • Diarrhoea or constipation — sometimes alternating bouts of constipation and diarrhoea
  • Mucus in the stool
  • Feeling sick (nausea)
  • Headache
  • Backache
  • Feeling quickly full after eating
  • Heartburn

For most people, IBS is a chronic condition, although there will likely be times when the signs and symptoms are worse and times when they improve or even disappear completely. Triggers vary from person to person.


The advice about fibre in treating IBS has changed over the years. Fibre (roughage – and other bulking agents) is the part of the food which is not absorbed into the body. It remains in your gut and is a main part of stools. There is a lot of fibre in fruit, vegetables, cereals, wholemeal bread, etc.

Some research studies have shown that a high-fibre diet helps symptoms in IBS; others have shown the opposite. In some people, perhaps particularly those with constipation, a high-fibre diet definitely helps. In others, often those with diarrhoea, a high-fibre diet makes symptoms worse. If you keep a symptom diary, you can work out which is true for you. Then adjust your fibre intake accordingly.

What seems to be the case is that the type of fibre is probably important. There are two main types of fibre – soluble fibre (which dissolves in water) and insoluble fibre. It is soluble fibre rather than insoluble fibre that seems to help ease symptoms in some cases. So, if you increase fibre, have more soluble fibre and try to minimise the insoluble fibre.

Dietary sources of soluble fibre include oats, nuts and seeds, some fruit and vegetables and pectins. A fibre supplement is also available from health stores.

Insoluble fibre is chiefly found in corn (maize) bran, wheat bran and some fruit and vegetables. In particular, avoid bran as a fibre supplement.

The low-fodmap diet

Recently, it has been discovered that a low-FODMAP diet may help some people with IBS.
FODMAP stands for Fermentable Oligosaccharides,Disaccharides, Monosaccharides, and Polyols. These are a group of carbohydrates found within foods, which may make IBS symptoms worse.

Examples of foods to avoid in a low-FODMAP diet include:

  • Certain fruits, such as apples, cherries, peaches and nectarines.
  • Some green vegetables, such as peas, cabbage, broccoli and brussels sprouts. Artificial sweeteners.
  • Foods high in lactose, such as milk, ice cream, cream cheeses, chocolate and sour cream.If you wish to try a low-FODMAP diet, you could discuss this with a natural health professional.


Probiotics are nutritional supplements that contain good germs (bacteria). That is, bacteria that normally live in the gut and seem to be beneficial. Taking probiotics may increase the good bacteria in the gut which may help to ward off bad bacteria that may have some effect on causing IBS symptoms.

Current guidelines about IBS include the following points about diet, which may help to minimise symptoms:•     Have regular meals and take time to eat at a leisurely pace.

  • Avoid missing meals or leaving long gaps between eating.
  • Drink at least eight cups of fluid per day, especially water or other non-caffeinated drinks. This helps to keep the stools (faeces) soft and easy to pass along the gut.
  • Restrict tea and coffee to three cups per day (as caffeine may be a factor in some people)
  • Restrict the amount of fizzy drinks that you have to a minimum.
  • Don’t drink too much alcohol. (Some people report an improvement in symptoms when they cut down from drinking a lot of alcohol.)
  • Limit fresh fruit to three portions (of 80g each) per day
  • Avoid eating onions and garlic.
  • If you have diarrhoea, avoid sorbitol, an artificial sweetener found in sugar-free sweets (including chewing gum) and in drinks, and in some diabetic and slimming products.
  • If you have a lot of wind and bloating, consider increasing your intake of oats (for example, oat-based breakfast cereal or porridge) and linseeds (up to one table spoon per day). You can buy linseeds from health stores.



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