Guts to live in our Guts
Our gastrointestinal tract harbors 500-600 different species of bacteria, which account for approximately 2 lbs of our total body weight.

The term flatus refers to a mixture of gases formed as a byproduct of the digestion process and aerophagia (swallowing air). Flatus mainly comprises nitrogen, carbon dioxide, oxygen, hydrogen, and methane.

The digestive process begins with mastication which is followed by the action of gastric juices in the stomach. This partially digested chyme then passes to the small intestine where it is further broken down by the combined action of bile and pancreatic juices as well as intestinal enzymes. Nutrient absorption occurs and the remaining chyme passes to the large intestine. This chyme mainly consists of sugars or carbohydrates which cannot be digested by our body, simply because it lacks the necessary enzymes. This undigested food is fermented by the bacteria, residing in the colon. Byproducts of this fermentation process are gases, namely, carbon dioxide, hydrogen, and methane. Carbon dioxide is also formed due to interaction of food with the stomach acids. The source for the remaining two components, nitrogen and oxygen, is swallowed air. Gases that have diffused from blood into the lumen are also a source of nitrogen.

Excess formation of gas is mainly due to improper diet, bad eating habits, talking while eating, or eating too fast. It could also be a side effect of certain medicines or due to gastrointestinal problems. Identifying the right cause can help you deal with the discomfort and pain in an efficient manner. The different causes have been explained below.

Aerophagia (or aerophagy) implies excessive swallowing of air. Without our knowledge, approximately 2-3 ml of air per swallow enters our stomach, during eating, drinking, or even while resting. This leads to gas formation in the stomach and intestines. Most of this gas is released via belching, whereas a small amount travels into the intestines. A few common activities and conditions leading to aerophagia are as follows:
  • Eating or drinking very quickly. In fact, 2-3 times more air gets swallowed while drinking. Excessive intake of carbonated drinks increases the incidence of aerophagia even more.
  • Excessive swallowing of saliva and air could be due to anxiety, mental trauma, and depression.
  • Smoking, chewing gum, and sucking on candies frequently also lead to hypersalivation and hence aerophagia.
  • Nasal congestion, snoring, and heavy exercises cause mouth breathing which adds to the amount of swallowed air.
  • Other reasons are wearing loose dentures, using straw while drinking, and talking while eating.
Gas-causing Food
Fiber-rich foods and foods high in starch and sugar are difficult to digest, and tend to accumulate in the colon. The fermentation of these carbohydrates by colonic bacteria leads to an increased production of gas. Such partially digestible carbohydrates are collectively called low-digestible carbohydrates (LDC). The intensity with which these LDCs cause flatulence varies from person to person.

According to the National Digestive Diseases Information Clearinghouse, (an information dissemination service under the US Department of Health and Human Services), the common foods that might lead to excessive gas formation are:
  • Starch: Potato, corn, pasta, and wheat
  • Fiber: Oat bran, beans, peas, wheat bran, and most fruits.
  • Sorbitol: Apple, peach, prune, and pear; artificially sweetened diet food and sugar-free candies.
  • Raffinose: Beans, cabbage, Brussels sprouts, broccoli, asparagus, and whole grains (in small amounts).
  • Fructose: Onion, artichoke, pear, and wheat; artificially sweetened drinks and juices.
Lactose Intolerance: People with lactose intolerance may experience symptoms like gas, bloating, diarrhea, nausea, and cramps. Lactose is a sugar abundantly present in milk and dairy products as well as processed food products like bread and salad dressings. This disaccharide sugar is broken down by the enzyme lactase. If this enzyme is absent or present in small amounts, the body is unable to digest lactose. As a result lactose passes down to the large intestine and is fermented by the bacteria present there. This leads to the release of gases, namely carbon dioxide, hydrogen, and methane.

Gluten Intolerance (Celiac Disease): It is characterized by an inherited inability to digest gluten, which eventually leads to abdominal cramps, bloating, and flatulence. Gluten is a protein present in wheat, rye, and barley. Undigested gluten damages the intestinal epithelium resulting in increased bacterial fermentation, which further leads to gas buildup.

Medical Conditions
Small Intestinal Bacterial Overgrowth (SIBO): As the name suggests, this condition is characterized by the growth of bacteria in the small intestine. Bacteria, that form a part of the normal flora of colon, begin to colonize parts of the small intestine, and start utilizing the partially digested chyme. This results in gas formation in the small intestine causing abdominal discomfort and flatulence. SIBO generally occurs due to inefficient functioning of the intestinal muscles or insufficient secretion of gastric acids.

Irritable Bowel Syndrome (IBS): This is the most common intestinal disorder, and is characterized by abdominal cramps and pain, flatulence, bloating, and alternative bouts of diarrhea and constipation. The exact cause is yet unknown, however it has been associated with intestinal infections, SIBO as well as stress and mental unrest.

Inflammatory Bowel Disease (IBD): Inflammatory bowel disease includes disorders that result in chronic inflammation of the gastrointestinal tract or parts of it, and hence cause increased flatulence and bloating. The two major disorders under IBD are Crohn's disease and ulcerative colitis. In Crohn's disease, the whole GI tract or a part of it can be inflamed and ulcerated, whereas ulcerative colitis specifically involves inflammation and ulceration of the colon. In these cases, intestinal obstruction may take place leading to bacterial growth and gas formation.

Gastritis: Gastritis involves ulceration and inflammation of the stomach lining due to bacterial infection, excess intake of alcohol, use of certain drugs like aspirin and ibuprofen for a long period, bile reflux, etc. Such inflammation causes improper digestion, abdominal pain, and flatulence. The major causative agent is a bacterium called Helicobacter pylori which resides in the mucosal lining of the stomach. The virulent strains release toxic proteins that cause cell injury or cell death, and induce an inflammatory reaction.

Certain medicines cause excessive gas as a side effect. Medicines with sorbitol, fructose as additives, and fiber supplements like Metamucil commonly cause flatulence. Metformin, which is a drug prescribed for the treatment of type 2 diabetes and Alli, which is a drug prescribed for obesity, are associated with excessive gas formation. Long-term use of antibiotics may disturb the normal gut flora resulting in increased incidences of flatulence.

Lack of Exercise
A sedentary lifestyle and lack of exercise does not directly contribute to gas formation but it leads to accumulation of the formed gases. Regular exercise helps to release the gases formed in the intestines and thus prevents the resulting pain and abdominal discomfort. However, it is important to note that improper breathing techniques while exercising may lead to increased aerophagia.

Flatulence is just another natural body process, but excess of it causes abdominal discomfort and pain, bloating, belching, and similar symptoms. So choose a healthy diet, identify and limit the consumption of food products that lead to excess gas formation in your body, especially if you are suffering from any of the above mentioned conditions.

Disclaimer: This Buzzle article is for informative purposes only, and should not be used as a replacement for expert medical advice.