Why do we fart after eating beans?

Beans are incredibly nutritious. They are brimmed with potassium that regulates the blood pressure, zinc that boosts the immune system, and an incredible combination of fiber and protein for a waist-slimming effect. However, after munching pinto bean chili, or baked beans, the benefits may be offset by the consequence that it brings – making you fart.

But, why do beans give us flatulence or gas? Let’s look at the process of how the stomach digests it.


After consuming refried beans, it goes to the small intestine. The small intestine is brimmed with digestive enzymes that strip any food you eat into pieces or bits. Through that, the body can better break them into even smaller components and absorb all necessary nutrients. Carbohydrates are broken down into simple sugars. Proteins are turned into amino acids or peptides. Meanwhile, fats are transformed into glycerol or fatty acids. The body then absorbs all nutrients through the intestinal walls, and use it as its fuel.

While it may seem a smooth process, this process is not as seamless when you eat beans. Their innate sweetness comes from oligosaccharides, which are a group of sugar produced when three to 10 simple sugars are combined together. Some most common oligosaccharides present in beans are verbascose, stachyose, and raffinose. What makes them unique is that these sugars are a large, strange type of molecules. Our digestive enzymes are not powerful enough to break down these substantial sugars into more feasible pieces. With that, the intestinal wall cannot absorb them, and they pass through the small intestine intact and unscathed.

What happens instead is that the tough oligosaccharides are transported to the colon where billions of good bacteria are awaiting to munch them. However, during their digestive activity, they produce small amounts of gas, such as nitrogen, carbon dioxide, hydrogen, and methane as a by-product.

To put it simply, beans have oligosaccharides. These are a group of sugars that cannot be digested or broken down by the body. They go straight into the lower gut where they are feasted on by bacteria that consumes sugar and release gas as a result. So, where do all the accumulated gas go? It is what you eventually release as a fart.

Well, you might probably be one of those who immensely love these legumes and won’t give up eating them despite the ‘disgusting’ result. Luckily, there’s now a solution so you could still indulge in baked beans or chili. You can avoid flatulence by taking gas-relieving supplements. One such product is Beano, which contains alpha-galactosidase, an enzyme derived from the fungus Aspergillus niger. The said enzyme is effective in breaking down oligosaccharides, the body’s own enzyme can’t digest.

Just put a few drops of the gas-relieving supplement into a glass of water and drink it up before consuming your meal. They are also available in pill or tablet form, which are useful in turning oligosaccharides into more manageable sugars, such as fructose, sucrose, and glucose.

Alternatively, you can also reduce the chances of flatulence by introducing beans slowly into your diet. That means that if you are not used to eating legumes. Then, it is advisable not to munch on them too much on a single meal. Including a massive amount of beans in your diet in a short period can quickly lead to gas accumulation.

Moreover, food preparation may also help. Soaking and rinsing dry beans prior to cooking can help reduce their oligosaccharide component. If you are using those in cans, rinse them in water until all bubbles are removed.

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