Most of us have experienced the occasional episode of bloating, particularly after overeating or eating a rich meal. For some, bloating can occur as a symptom of other digestive disorders, such as Irritable Bowel Syndrome (IBS) or indigestion. But for others, bloating occurs regularly without other digestive problems and can be distressing.
The causes of bloating, and therefore the treatment, will vary from one person to the next. Following are some of the most common causes of bloating.
- Constipation is a common cause of bloating, although not everyone who experiences constipation will also have symptoms of bloating and discomfort.
- Irritable Bowel Syndrome (IBS) is probably the most common cause of bloating, with up to 90% of people with IBS reporting bloating among their symptoms. Other symptoms include abdominal pain and discomfort, along with changes in bowel habits. Interestingly, people with IBS don’t actually produce more gas, but the nerves in their bowel are more sensitive to the gas they produce. Some people with IBS also have problems with how the muscles in the bowel contract, so that gas gets trapped in the small bowel rather than moving through.
- FODMAP sensitivity. For reasons we don’t fully understand, certain foods are not well tolerated by some individuals. In particular, a group of short-chain carbohydrates, known collectively as FODMAPs, are poorly absorbed from the small intestine in some people. As a result, they pass down into the large intestine where they are fermented by gut bacteria to generate gas, causing wind, bloating and distention. FODMAPs include lactose (milk sugars), fructose (fruit sugars), fructans (found in wheat, rye, barley, onion, garlic and certain vegetables, fruit and nuts), polyols (found in many artificial sweeteners and naturally in some fruits and vegetables) and galacto-oligosaccharides (found in legumes and some nuts and vegetables).
- Lactose intolerance occurs because of a deficiency of the enzyme lactase, whose job it is to break down lactose to allow it to be absorbed. Gut bacteria ferment unabsorbed lactose, resulting in bloating, typically along with nausea, abdominal cramps and diarrhoea.
- Coeliac disease is a condition where eating gluten causes an immune reaction in the small intestine, damaging the intestinal wall and reducing its ability to absorb nutrients from food. This can cause gut symptoms, including bloating, along with diarrhoea, nausea, and abdominal pain. Weight loss and deficiencies of certain vitamins and minerals, including iron and vitamin D, are also common, although some people have no symptoms at all.
If you are experiencing persistent bloating, it is important to see your doctor, who can help you determine the cause. Once you know the cause of your bloating, you can put a plan in place to manage it, which may include dietary and lifestyle changes, along with medications where needed.
While bloating can be unpleasant and uncomfortable, in most cases, the cause of your bloating isn’t anything serious. Bloating will typically fluctuate in intensity and commonly improves overnight and gets worse over the day, particularly after eating. If your bloating is persistent across the day and night, gets progressively worse over time and/or is associated with other symptoms such as weight loss, nausea, abdominal pain, changes in your bowel habits or blood in your stools, then it is important to discuss this with your doctor to rule out any more serious causes.
References
Agrawal A, Whorwell PJ. Review article: abdominal bloating and distension in functional gastrointestinal disorders—epidemiology and exploration of possible mechanisms. Aliment Pharmacol Ther. 2008 Jan 1;27(1):2-10. doi: 10.1111/j.1365-2036.2007.03549.x. Epub 2007 Oct 11. PMID: 17931344.
Ong DK, Mitchell SB, Barrett JS, Shepherd SJ, Irving PM, Biesiekierski JR, Smith S, Gibson PR, Muir JG. Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome. J Gastroenterol Hepatol. 2010 Aug;25(8):1366-73. doi: 10.1111/j.1440-1746.2010.06370.x. PMID: 20659225.
Sullivan SN. Functional abdominal bloating with distention. ISRN Gastroenterol. 2012;2012:721820. doi: 10.5402/2012/721820. Epub 2012 Jun 19. PMID: 22778978; PMCID: PMC3388350.
Bolin T. Wind: Problems with intestinal gas. Australian Family Physician 2013; 42(5): 280-283. Australian Family Physician: Wind Problems with intestinal gas
