Digestive Health

29 December 2010

Always bloated? Watch what you eat

Do you suffer from flatulence and constant bloating? Maybe it's time to take a closer look at what you eat - your diet may be to blame, DietDoc says.


The DietDoc Forum is flooded with questions from Health24 users who complain about flatulence or gas, and bloating.

Most of these users have self-diagnosed themselves as having irritable bowel syndrome (IBS) or spastic colon. And many of them are embarrassed by their condition and often experience great discomfort and pain.

It is, therefore, important that we should consider some aspects of these symptoms and how they should be treated. A recent article published in the Medical Chronicle by Dr Herbie Schneider (2005) sheds some light on this subject.

Gas production
The human digestive system usually contains about 100-200 ml of gas, which is primarily produced in the colon by bacterial breakdown of various foods. Foods rich in dietary fibre may increase gas production because the fibre acts as a substrate for microbiological processes.

The gasses we produce in our intestines are mainly hydrogen, methane and carbon dioxide, plus a small amount of the so-called "smelly gasses" such as hydrogen sulphide, ammonia and volatile fatty acids. The latter group of gasses tend to cause embarrassment because of their strong, unpleasant smell.

Dr Herbie Schneider states that bloating is "a key symptom in IBS" and occurs in "about 30% of adults". Usually the patient wakes up with a flat abdomen which distends and blows up as the day progresses, so that the patient often complains of "looking pregnant" by the time he or she goes to bed.

In women, bloating may become worse during menstruation. Tests have indicated that although individuals who suffer from bloating do not actually produce much more gas than normal people, their abdominal dimensions can increase by as much as 3-4 cm during the day.

Studies have also indicated that bloaters do not handle the contents of the bowel as efficiently as individuals who do not suffer from bloating. Interestingly enough, it is not the colon as was long suspected that hampers the transit of intestinal gas content, but the small bowel.

Various mechanisms such as reduced stimulation and increased inhibition, result in the gas being trapped in the intestine, which then leads to abdominal distention or bloating.

It is essential that anyone who suffers from excess gas production and/or bloating should have a medical examination to determine what is causing these phenomena. Not every patient with gas and bloating suffers from IBS or spastic colon. If you are troubled by these unpleasant symptoms, pay a visit to your doctor.

The following conditions are also likely to cause gas production and bloating:

  • Lactose intolerance. Lactose is primarily found in milk. If you are intolerant to this sugar, you would experience flatulence and bloating whenever you drink milk or use certain milk products and other commercial products that contain cow's milk. Treatment is to cut out all foods that contain cow's milk.
  • Overgrowth of bacteria in the small intestine. Research has identified that bacterial overgrowth in the small intestine is common in patients with IBS. This type of condition may respond to the use of probiotics ("good microorganisms"). There are many different probiotics on the market and you can ask your chemist or health shop for probiotic products to normalise the gut flora.
  • Fructose intolerance. Fructose is a sugar that is found in fruit, honey and some commercial products. Up to 30% of IBS patients have been found to be intolerant to fructose. The pronounced increase in the use of fruit juices in recent years may be partly responsible for the rise in IBS.

It is important to determine exactly what is causing flatulence and bloating, and to eliminate the possibility of fructose or lactose intolerance and bacterial overgrowth before you start treating a patient for IBS.

Offending foods
Certain foods are more inclined to cause flatulence and bloating because they contain compounds that promote gas formation in the intestines.

a) Legumes
Legumes or dry beans, peas, lentils, soya and soya products like textured vegetable protein, meat replacers and tofu, tend to cause gas production.

If you find that you react to these foods, you will have to read food labels very, very carefully because nowadays most processed foods, including all processed meats, pies, sausages (except boerewors), many canned foods and even bread, contain textured vegetable protein.

This can make life very difficult because an individual who is sensitive to legumes may find that she can practically eat no commercially prepared foods anymore.

b) Milk and dairy products
Cow's milk, ice cream, cheeses, and foods that contain cow's milk or cheese can cause problems, particularly if the patient is lactose intolerant.

c) Vegetables
The entire Brassica family (cabbage, broccoli, Brussels sprouts, cauliflower), cucumber (especially those with a hard skin), raw onions and garlic, asparagus, potatoes, and turnips tend to promote gas production.

In some cases, you may find that cooking reduces the discomfort - for example some people can eat cooked onions and garlic without any symptoms. English cucumbers are also less likely to cause bloating than hard-skinned cucumbers.

d) Fruits
Dried fruit tends to have a laxative action and may be too harsh for your digestive system. If you suffer from fructose intolerance, you will have to cut out all fruit, fruit juices and processed products that contain fruit or fructose.

e) Wheat-containing foods
All breads, crackers, biscuits, cereals and cakes that contain wheat may contribute to gas formation in sensitive individuals.

f) Fatty foods
Deep-fried foods or foods with a high fat content may slow down digestion and cause discomfort. Such foods should be avoided and replaced with low-fat foods instead.

g) Drinks
The gas in carbonated beverages and some types of alcohol can increase gas production and should also be avoided.

You may find it highly confusing to try and sort out exactly what you can or cannot eat if you suffer from flatulence and bloating. Consult a clinical dietician to sort out your diet and menu plans for you. – (Dr Ingrid van Heerden, DietDoc)

(Reference: Schneider, H (2005). Understanding Intestinal Gas & Bloating. Medical Chronicle. September, 2005, p 53)


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Digestive Health Expert

Dr. Estelle Wilken is a Senior Specialist in Internal Medicine and Gastroenterology at Tygerberg Hospital. She obtained her MBChB in 1976, her MMed (Int) in 1991 and her gastroenterology registration in 1995.

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