Doctor explains how to know if it is lactose intolerance or another digestive issue: Diagnosis, when to see doctor and treatment

Many people with lactose intolerance can manage small amounts of dairy. If symptoms persist without dairy, it may point to another condition.

Lactose intolerance is a common digestive condition where the body cannot properly break down lactose, the natural sugar found in milk and dairy products, according to the National Institutes of Health. Since it is a digestive issue and dairy is not always consumed on its own, it is quite easy to mistake lactose intolerance for other digestive issues.

In an interaction with HT Lifestyle, Dr Adarsh C K, HOD and senior consultant - medical gastroenterology, hepatology and advanced endoscopy, Gleneagles Hospitals, explained what lactose intolerance actually looks like, how you can tell it apart from other digestive issues, how to diagnose it, when someone should see a doctor, and more.

How to tell lactose intolerance apart from other digestive problems that look similar?

Time and pattern are the best clues, according to Dr Adarsh. He explained, “In lactose intolerance, symptoms like bloating, gas, cramping, and loose stools start within 30 minutes or two hours of having milk or milk-based foods. Lactose intolerance also scales with the amount. For example, a splash of milk in tea may be fine, but with a large glass of milk or a bowl of kheer, some may not be able to tolerate it.”

A paneer wrap, a milkshake, or a bowl of cereal with milk also contains sugar, fat, wheat, and other fermentable carbohydrates, all of which could be triggers for digestive issues. (Picture credit: Freepik)

Meanwhile, Dr Adarsh stressed that other digestive conditions behave differently. “In irritable bowel syndrome, symptoms flare up with several triggers like wheat, irregular meals, onions, stress, and not just dairy. In coeliac disease, the problem is gluten, and it can also come with weight loss, anaemia, and nutritional deficiencies,” he added.

Lastly, he stressed that if the symptoms of lactose intolerance persist even when you avoid dairy or are accompanied by blood in stool, night-time diarrhoea, or unexplained weight loss, lactose is unlikely to be the problem.

Why might bloating, gas, and abdominal discomfort after dairy have causes beyond lactose?

Explaining why that is the case, Dr Adarsh stressed that dairy is rarely eaten on its own, and added, “A paneer wrap, a milkshake, or a bowl of cereal with milk also contains sugar, fat, wheat, and other fermentable carbohydrates, all of which could be triggers.”

In lactose intolerance, symptoms such as bloating, gas, cramping, and loose stools start within 30 minutes to 2 hours after consuming milk or milk-based foods.

Moreover, he stated that several gut conditions can also make dairy seem like the culprit. “Small intestinal bacterial overgrowth (SIBO) causes bacteria to ferment sugars early in the gut, producing gas and bloating. Irritable bowel syndrome makes the gut more sensitive, so normal amounts of gas can also make people feel uncomfortable.”

He further explained, “Coeliac disease and inflammatory bowel disease can damage the gut lining, which reduces lactase, the enzyme that digests lactose. In these cases, lactose intolerance is a result of the underlying disease and not the primary problem. Being allergic to cow milk protein is also another possibility. It is an immune reaction and not a digestive one. This can cause hives, wheezing, and vomiting.”

How is lactose intolerance diagnosed, and when should someone see a doctor?

The first step, according to Dr Adarsh, is to remove dairy products for two to three weeks and then reintroduce them. “See whether the symptoms disappear and return. If you are unclear, a hydrogen breath test can help with a diagnosis. Here, a patient drinks a measured dose of lactose solution, and the hydrogen in their breath is tracked over the next few hours. A high reading would mean that the lactose is being fermented by the gut bacteria but not digested,” Dr Adarsh explained.

Blood glucose tests and stool tests are used less often to diagnose lactose intolerance. (Image by Freepik)

He also suggested blood glucose tests and stool tests, though they are used less often. “A small intestinal biopsy is rarely needed, but it may be done if another condition is suspected. If you observe blood in the stool, unreasonable weight loss, persistent diarrhoea, anaemia, fever or pain, consult a doctor,” he cautioned, suggesting not to cut out entire food groups without a diagnosis as well. “Self-diagnosis can delay finding the condition that needs proper treatment.”

What is the treatment for lactose intolerance?

“Giving up dairy completely is unnecessary. Tolerance varies among people, and many manage small proportions well. Curd, buttermilk, paneer, and hard cheeses tend to be easier to digest than milk as they contain less lactose or have been partially fermented. Lactose-free milk is also widely available. Lactase enzyme tablets can also be taken with a dairy-containing meal if avoiding the meal is not possible,” Dr Adarsh explained.

In the end, the one thing he cautioned against is cutting dairy out entirely and for good. He explained, “Dairy is a major source of calcium, vitamin D, and protein, so if you do plan on cutting it out, you need to replace these through leafy greens, ragi or supplements, with guidance from a doctor or dietitian. If symptoms continue despite these changes, that is a signal to look for another cause rather than simply cut back further.”

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.