What is lactose intolerance? Symptoms, Causes, Diagnosis and Treatment

Metabolic health

Have you ever had that awkward moment when you’re out with friends, eyeing that delicious-looking cheese pizza, you wanted to eat it so bad that you got your tummy at trouble after enjoying a cheesy pizza! Even after you knew your lactose intolerance is about to stage a not-so-pleasant protest. Well life with lactose intolerance might seem easy but it’s not that easy as it seems. Let’s understand what lactose intolerance is. What are its symptoms, causes, how it can get diagnosed and lactose intolerance treatment. 

What Is Lactose Intolerance?

Lactose intolerance is a common digestive disorder that affects millions of people worldwide. It occurs when the body has difficulty digesting lactose, a sugar found in milk and dairy products. Do not confuse lactose intolerance with a milk allergy. A milk allergy involves the immune system’s response to proteins in milk, while lactose intolerance is a non-allergic, digestive issue related to the body’s inability to properly digest lactose.

What Causes Lactose Intolerance? 

Generally, the lactose is broken down by an enzyme called lactase which is produced by cells in the lining of the small intestine. Either lactase is less or in lack the body is unable to digest the dairy products because of it. People dealing with lactose intolerance are unable to fully digest the lactose (sugar) in milk. As a result, they have gas, bloating and diarrhoea after consuming any dairy products. This condition is called lactose malabsorption, though it is usually harmless, but its symptoms can be a bit uncomfortable.

Congenital lactase deficiency is a digestive disorder in which infants are unable to break down the lactose in breast milk or formula. In this the infants might suffer severe diarrhoea, dehydration and weight loss if the affected infants are not given a lactose-free milk formula to drink. Sometimes lactose intolerance in adulthood can also be caused by the reduced production of lactase after infancy which is also called lactase non-persistence. 

Often it is seen that people dealing with lactase non persistence are able to digest dairy products such as cheese or yogurt without discomfort while they are getting affected from fresh milk. This is because cheese and yogurt are made using fermentation processes that break down the lactose in milk. Hence, they can easily consume dairy products that are not fermented by fresh milk. 

Gut Sensitivity

From time to time we all occasionally consume things that we can’t fully digest. Some of the dietary fibers and sugars go straight  to nourish the bacteria residing in our gut. Well for most of us, this is a manageable process with minimal discomfort. However, the key here is that all the individuals are different. Our genes, the health of our intestines, our individual sensitivities, and our diets all play a role. The gut microbiome, distinct from the bacteria living in the colon, handle lactose differently in every individual. The symptoms can guide you to discover your own tolerance level for lactose.

What Are Symptoms of Lactose Intolerance?

Now that we are clear on the concept of lactose intolerance and what are causes of lactose intolerance. Let’s understand the symptoms of lactose intolerance. 

Lactose intolerance does not hit like you just drank a glass of milk and you are having diarrhea. The symptoms of lactose intolerance may vary person to person. Sometimes the intensity is so high that symptoms usually appear within 30 minutes and sometimes it takes up to two hours after consuming dairy products. Some of the common symptoms include:

Gas: Increased gas production, leading to flatulence and sometimes abdominal cramps.

Bloating: Many individuals with lactose intolerance experience bloating, which is a feeling of fullness and discomfort in the abdomen.

Stomach aches: Mild to moderate stomach pain and discomfort are often reported after consuming any dairy products. 

Nausea: Some individuals may feel nauseous after consuming lactose.

Vomiting: In severe cases, lactose intolerance can lead to vomiting.

DiarrhoeaFrequent episodes of loose, watery stools can occur as the undigested lactose draws extra water into the intestines.

Diagnosis: How do you know if you’re lactose intolerant?

Lactose intolerance diagnosis includes medical evaluation and testing. The common methods are: 

Blood Sugar Test

This test measures the blood sugar levels before and after you ingest lactose solution. If your blood sugar doesn’t rise, it shows you’re not absorbing the lactose.

Hydrogen Breath Test

This breath test measures hydrogen  and methane gas levels in breath after consuming lactose. If you have higher levels of these gasses after ingesting lactose, it’s because your gut bacteria are fermenting the lactose, releasing the gas in your colon that can be measured later in your breath.

Stool Acidity Test

This test is generally performed on small children and infants. After feeding them an infant lactose they take stool samples (poop) with them to analyze its levels of lactic acid and other byproducts. It is done to understand whether the body is absorbing the lactose or not.

What Is the treatment for Lactose Intolerance? 

While lactose intolerance cannot be cured, its symptoms can be managed effectively through dietary changes and, in some cases, lactase supplements. Here are some treatment for managing lactose intolerance:

Limit Dairy Consumption

Avoid or reduce the intake of milk and dairy products. Many lactose-free and dairy-free alternatives are available in the market such as lactose-free milk, almond milk, and dairy-free cheese in your daily life. 

Lactase Supplements

As people suffering from lactose intolerance can’t produce lactase naturally. These supplements are given to them for digestion. These lactase supplements give enough lactase to the body which is needed to break down lactose. People can take these as tablets or drops before consuming lactose.

Gradual Reintroduction

Some individuals with lactose intolerance can tolerate small amounts of dairy without symptoms. Gradually reintroduce dairy into your diet to determine your tolerance level.

Read Labels

Be vigilant about checking food labels for hidden sources of lactose, as it can be found in unexpected places like processed foods and medications.


Some people find relief from lactose intolerance symptoms by taking probiotic supplements that contain lactase-producing bacteria. Your doctor or clinical nutritionist might suggest some specific probiotics that can help alleviate lactose intolerance.

Lactose intolerance, though common, can be managed effectively with dietary modifications and enzyme supplements. Understanding its scientific and metabolic aspects is crucial for individuals dealing with this condition. If you suspect lactose intolerance, consult a healthcare professional for proper diagnosis and guidance on managing your dietary choices to maintain optimal metabolic health.