At WiseGEEK, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.
Gasses can become trapped in the stomach, leading to bloating and belching. Bloating and belching are two possible results from the same conditions, and they often occur together. Excessive volumes of trapped gas can make the stomach bloated or distended. Belching is the body’s simplest, most effective tool for relieving that pressure. Without belching, gasses would have to pass through the entire digestive tract, which can be an uncomfortable and sometimes painful process.
Bloating is caused by high volumes of gas trapped in the stomach. The stomach feels uncomfortably full and might be painful. Often, a disruption or delay of the digestion process is responsible, preventing food from passing normally and trapping the gas in the stomach.
Belching or burping, on the other hand, is an action that releases these gasses from the stomach, relieving pressure and helping to prevent or relieve bloating. A muscle called the lower esophageal sphincter (LES) is responsible for keeping the stomach’s contents from rising into the esophagus, but it can relax to release some of the gas back through the esophagus and out of the mouth as a burp. Under sufficient pressure, the gas also might force its way through the LES.
Gasses are present in every stomach, although normally, they are not present in levels that cause bloating and belching. These gasses come primarily from two types of sources: atmospheric and dietary. Air is swallowed along with food, and digestion causes gasses to be released. Some foods, such as carbonated drinks, contain high volumes of gas and are especially likely to cause bloating and belching, but high levels of gasses from any source will result in bloating and belching.
When eating, some air is swallowed along with food. For most people, 20 percent to 60 percent of the gas in the digestive tract is atmospheric. Air also is swallowed when one chews gum, sucks on hard candy or smokes. Other conditions that can cause people to swallow air include poorly fitting dentures or postnasal drip. Some people habitually swallow air, especially in moments of distress, which can cause bloating and belching.
Certain foods produce more gas during digestion. Baked beans, cabbage and Brussels sprouts are notorious for producing gas. Fructose, the sugar found in most fruits, produces high volumes of gas as well. Other sources of gas include onions, broccoli, wheat and asparagus. For some people, the sugar-free sweetener sorbitol also can produce enough gas to cause bloating and belching.