Can you become lactose intolerant later in life?

By Katy Brodski-Quigley, MD Jun 30, 2022 • 2 min

Lactose intolerance is a common condition, affecting over 60% of people worldwide. Many people find that while they once had no trouble with dairy products, they may develop an intolerance as they age. The condition can be uncomfortable and can cause diarrhea, nausea, bloating and abdominal pain.

Primary lactase deficiency

Lactose intolerance can affect people of all ages. However, while most babies have no trouble with lactose, the ability of the intestine to digest lactose can diminish with age. It's common for someone to develop lactose intolerance as an older child, an adult or even as an older adult.

Primary lactase deficiency occurs when the body’s ability to make the lactase enzyme decreases as a person gets older. Lactase is needed to digest lactose, the sugar found in milk and other dairy products. If lactase levels are low, undigested lactose passes into your colon and gets broken down by bacteria, causing unpleasant digestive symptoms. This is the most common cause of lactose intolerance.

Other causes of lactose intolerance

Some illnesses or trauma to the intestine, such as celiac disease, Crohn's disease or radiation, can also cause lactose intolerance. This is called secondary lactase deficiency. In these cases, as the person recovers from their condition, their lactose intolerance may resolve.

Lactose intolerance can be a very uncomfortable condition. Choosing lactose-free dairy products or taking lactase pills before consuming lactose can help people with lactose intolerance reduce the risk of uncomfortable symptoms.

Published June 2022.