Normal Stomach Noises
Noises within the stomach and bowels are a normal part of gastrointestinal physiology. Most of the time these noises are inaudible to the human ear but when hungry or after eating, bowel sounds may be audible to the person or even others in the near vicinity. This is not abnormal. However loud and excessive bowel sounds (audible and hyperactive) should be investigated, especially if it is persistent or accompanied by other signs and symptoms.
Stomach noises may be described as growling, gurgling or even rumbling. All these noises are medically known as borborygmi (singular ~ borborygmus). Despite the descriptive terms attributed to the various types of stomach noises, it is difficult to isolate the exact cause behind each type of sound. In most cases, the sounds are so similar that these terms are used interchangeably.
Why does the stomach make noises?
Movement through the gut is almost constant with periods of greater activity, usually after eating. However, even hours after eating when the gastrointestinal walls are not forcefully contracting and relaxing, some movement of the substances within it are still occuring. The reasons for the various stomach and bowel noises are due to :
- Movement of food and chyme through the alimentary tract as the muscle contractions of the gastrointestinal wall pushes it through the gut as well as churning and breaking it down to aid with digestion.
- Stomach gas and intestinal gas, which is produced by chemical digestion and bacterial breakdown of food in the gut.
- Indigestible foods and hard substances within the gut.
These factors that contribute to stomach noises are a normal part of human physiology and anatomy as well as due to diet and lifestyle.
Causes of Loud Stomach Noises
While stomach noises are a normal occurrence, at times these sounds are loud and excessive. This can be disturbing and embarrassing to a person but may not be due to any serious medical disorder. If accompanied by other symptoms like excessive belching, excessive flatulence, abdominal pain, abdominal bloating or changes in bowel movement (like diarrhea or constipation) then it can be quite distressing and is possibly a symptom of some underlying gastrointestinal disturbance.
Broadly, loud and hyperactive stomach noises can be attributed to :
- hypermotility of the gut (excessive movement)
- partial obstruction within the gut
- excessive gas in the gut
- excessive fluid in the gut
- maldigestion or malabsorption
This is where the peristaltic mechanism of the stomach and bowels are overactive. Food is churned and pushed through the gut at a faster rate. Digestion may also be affected. Hypermotility is often associated with diarrhea and may be a result of various causes like :
- Infections – infectious gastroenteritis, enteritis and colitis.
- Chemical irritation – excess alcohol consumption, toxins like with food poisoning and ingested poisons.
- Functional – diarrhea-predominant irritable bowel syndrome (IBS).
- Psychosomatic – anxiety, stress, fear and other strong emotions (refer to Nervous Stomach).
- Allergic – food allergies.
- Dietary – food intolerances and malabsorption syndromes.
The movement of food or chyme through a narrowing within the gut may cause unusual noises as the muscles of the gut wall attempt to force the food through the narrowing. These sounds may not be evident if the obstruction lies in the distal parts of the colon where the waste material is almost solid, although it will present with pencil thin stools.
Some of the causes include :
- foreign bodies
However, it is not only slow stomach emptying that may cause louder gastrointestinal noises. The borborygmi may also be linked to a blockage in the bowels (small or large intestine) which can back up the gut contents.
Excess gas in the gut may occur for a number of reasons varying from overeating to gassy foods and bacterial overgrowth. The churning of gas with the liquid chyme within the gut, coupled with movement of gas pockets through the gut may contribute to a growling or rumbling noise. However, most of the upper gastrointestinal gas is not due to these causes but rather from excessive air swallowing (aerophagia). If this gas is increased substantially for any of the reasons mentioned above then the growling and rumbling will be louder.
This may be a result of certain process that give rise to osmotic or secretory diarrhea. Osmotic diarrhea is a result of solutes that cannot be absorbed within the gut as with lactose intolerance. Other food intolerances may produce a similar effect as may be seen with a substance like sorbitol that is used as a sugar replacement, particularly in sugar fee gum.
Secretory diarrhea arises due to water being passed into the lumen of the gut as is seen with bacterial toxins, certain secretagogues like diet chewing gum and so on. The excessive fluid will invariably lead to a loose, watery stool. Typically, gurgling sounds will be evident as hypermotility is often present as well and the rushing of large amounts of fluid is audible.
Malabsorption and Maldigestion
Both maldigestion and malabsorption will lead to excessive gas and/or fluid in the gut. These conditions affect the breakdown of food into simpler substances (maldigestion). It is often linked to problems with digestive enzymes, as is seen in lactose intolerance or pancreatic exocrine insufficiency. If these nutrients cannot be broken down then it cannot be absorbed.
Apart from food that is not broken down properly, absorptive problems may be due to conditions with the intestinal lining. This is often seen when the lining of the bowels are inflamed in diseases such as inflammatory bowel disease, infectious enterocolitis or celiac disease. Nutrients cannot cross the epithelial barrier due to the inflammation and therefore remain in the gut.
When these nutrients pass through the gut, it draws out fluid from the body and into the bowels. Therefore the fluid within the bowels increases. The residual nutrients are also consumed by the bacteria within the gut thereby increasing gas production. Lastly there is irritation of the bowels which leads to increased movement. The combination of the increased movement, increased gas and increased fluid results in louder growling and rumbling noises within the bowels.
Last updated on September 5, 2018.