Why Beans Cause Gas

It's not exactly something you would keep track of, but most people pass gas between 13 and 21 times a day. It can happen even while you're asleep.

Gas is part of the natural digestive process. However, many people find gas embarrassing, particularly if they pass an excessive amount of gas.

It's true that some foods cause someone to produce more gas than others. In particular, foods with a high fiber content are frequent offenders. They can cause bloating, too.

It's also true that most people do not get enough fiber in their diet and should eat more fibrous foods. One food that has an especially notorious reputation when it comes to gas is beans, a member of the legume family.

Beans are well known for their ability to cause flatulence, but the reason may surprise you. This article explains why they have this effect, and what you can do about it.

Understanding Gas

Intestinal gas consists of hydrogen, nitrogen, and carbon dioxide. These gasses are odorless. Another element exists in the intestinal gas of about one-third of people: methane.

It's unclear why some people's bodies produce methane and others do not. One way to tell if there is methane in gas is to look at the stool after going to the bathroom. People who produce methane typically have stools that float in water.

Why Beans Cause Gas

Beans (legumes) cause gas because they contain a particular type of sugar, called an oligosaccharide, that the human body cannot fully digest. Other sugars are broken down and absorbed in the small intestine. But the human body does not produce an enzyme that breaks down oligosaccharides.

Oligosaccharides in beans make it all the way to the large intestine undigested. Bacteria in the large intestine finally feed on these sugars.

Doing so causes fermentation (a chemical breakdown) and the production of gas. We release that gas as flatulence.

Other foods that enter the large intestine without being absorbed in the small intestine can cause gas, too. And stress can affect digestion and nutrient absorption. The result? More gas.

Preventing Gas From Beans

To prevent gas that is caused by eating beans or other foods, the oligosaccharides must be broken down before they reach the large intestine.

An enzyme called alpha-galactosidase can do this. But you will need help since the human body does not produce this enzyme.

You can take this enzyme as a supplement right before a meal. Derived from the fungus Aspergillus niger, it is available in pill form under the brand name Beano and others.

Alpha-galactosidase may also increase levels of a sugar called galactose in the blood. People with the genetic disease galactosemia should not use it. People with this disorder can't process galactose, so the sugar builds up in the body to toxic levels and can lead to a wide range of complications.

Summary

Beans cause gas because they contain a type of sugar, called oligosaccharide, that the body cannot break down. Gas can cause pain and discomfort, but there is a supplement you can take for relief.

A Word From Verywell

As long as it's not causing pain or excessive bloating, gas is a normal part of the digestive process. In fact, gas is an indication that things are working the way they should in the intestines.

Gas doesn't cause any real harm, but taking steps to minimize it may be a priority if it bothers you or others. Talk to your physician if you believe you experience too much gas or discomfort.