Why does lactose cause bloating?

Lactose is a sugar found in milk and dairy products. For the body to digest lactose properly, it needs an enzyme called lactase, which is produced in the small intestine.

Lactase breaks down lactose into two simpler sugars, glucose and galactose, which can be absorbed into the bloodstream and used as a source of energy.

Some people have a deficiency or reduced production of lactase, leading to a condition called lactose intolerance. Individuals with lactose intolerance have difficulty digesting lactose.

When undigested lactose reaches the large intestine, it can lead to various gastrointestinal symptoms, including bloating. The undigested sugars remain in the small intestine for longer than they should, enabling gut bacteria to ferment it.

Fermentation is a process that produces a lot of gases, including hydrogen, carbon dioxide, and methane. The accumulation of these gases in the intestines leads to bloating and flatulence (excessive gas release).

The presence of undigested lactose in the colon can draw water into the intestine, causing an osmotic effect. This can result in diarrhea as the body tries to flush out undigested lactose and gases.

The severity of lactose intolerance-related bloating can vary from person to person. Some of the factors that impact a person’s ability to digest lactase include the amount of lactose consumed, the person's level of lactase production, and the type of gut bacteria present.

Try consuming lactose-free dairy products to manage lactose intolerance and its unpleasant  symptoms. Consider lactose-free and dairy-free alternatives like nut milk, oat milk, soy milk, and lactose-free cheese and yogurt. Some fermented dairy products, such as yogurt and kefir, may also be better tolerated since the fermentation process reduces lactose content.