Lactose intolerance, also known as lactose sensitivity, occurs when the body is unable to digest lactose, a natural sugar found in milk and its derivatives. When lactose passes through the colon without proper digestion, it can cause some uncomfortable symptoms such as gas, abdominal pain, and bloating.

Some individuals are highly sensitive to lactose and cannot consume any dairy products, while others can consume small amounts without issues. Lactose intolerance is more common among adults, especially in African American, Asian, and Hispanic populations, and less common in people of European descent. Managing meals and ensuring adequate calcium intake can be a challenge for those affected.

Symptoms of Lactose Intolerance

Symptoms of lactose intolerance vary from mild to severe depending on the amount of lactase enzyme produced by the body. These symptoms typically appear 30 minutes to two hours after consuming a dairy product and may include:

Bloating

Abdominal pain and cramping

Gassiness with audible rumbling

Diarrhea and loose stools

Vomiting

People who experience these symptoms may believe they are lactose intolerant. The best way to confirm this is to avoid consuming dairy for a set period and monitor whether symptoms resolve. If they disappear, one can then try consuming small amounts of dairy products and observe if symptoms return.

In some cases, individuals who previously had no issues with dairy may develop lactose intolerance, with the likelihood increasing with age.

Causes and Risk Factors of Lactose Intolerance

Lactose intolerance occurs when the small intestine doesn't produce enough lactase, the enzyme required to break down the sugar in milk and its derivatives. This condition is often genetic and may start showing symptoms during adolescence or later in life. Most individuals with this type of intolerance can tolerate small amounts of dairy without experiencing symptoms.

In certain cases, the small intestine may stop producing lactase due to an illness such as gastroenteritis or chronic conditions like cystic fibrosis, or after a surgery to remove part of the small intestine. In these cases, the issue may persist long-term.

In rare instances, some babies are born with lactose intolerance, while premature infants may temporarily have a reduced ability to produce lactase, making them temporarily lactose intolerant.

Complications of Lactose Intolerance

In most cases, lactose intolerance doesn't lead to any serious complications.

Diagnosis of Lactose Intolerance

Lactose intolerance can be diagnosed through a series of questions regarding the patient’s symptoms. A doctor may ask the patient to refrain from consuming dairy products for a period to see if symptoms improve.

In certain cases, further tests may be performed to confirm the diagnosis, including:

Hydrogen Breath Test: This is the most accurate test to diagnose lactose intolerance. The patient is asked to avoid certain foods and medications, as well as smoking, before the test. On the day of the test, the patient drinks a lactose solution and then exhales into a device multiple times over the course of two hours. High hydrogen levels in the breath suggest lactose intolerance.

This test is not typically performed on young children due to the possibility of causing diarrhea.

Lactose Tolerance Test: This test measures blood sugar levels after consuming lactose. The patient is asked to fast before the test, then drink a lactose solution. Blood sugar levels are measured every 30 minutes for two hours. If no rise in blood sugar is observed, it indicates lactose intolerance.

This test is generally avoided for individuals with diabetes or young children.

Stool Acidity Test: This test measures the acidity in the colon. A stool sample is collected and tested in the lab. The presence of acids in the stool suggests the body isn't digesting lactose properly. This test is suitable for young children and infants.

Treatment of Lactose Intolerance

There is no cure for lactose intolerance, but symptoms can be alleviated by reducing or eliminating dairy consumption. Individuals with lactose intolerance typically choose products with lower lactose content or opt for dairy alternatives such as soy milk and soy-based cheeses.

Some individuals can tolerate yogurt, especially probiotic-rich varieties, or take lactase enzyme supplements to help break down lactose. Over time, people with lactose intolerance often become better at managing their diet to avoid symptoms and adopt habits to alleviate gas and other discomforts.

A common concern for people with lactose intolerance is ensuring adequate calcium intake, as dairy products are a primary source. Alternative sources of calcium include:

Vegetables such as broccoli, okra, and certain types of cabbage

Canned sardines, tuna, and salmon

Calcium-fortified juices

Whole grains

Calcium-rich soy products like soy milk, tofu, and edamame

Almonds

Since many people, even those who can tolerate dairy, do not consume enough calcium, dietary supplements are often recommended.

Prevention of Lactose Intolerance

Since lactose intolerance is typically genetic, there is no way to prevent it.