Your browser does not support JavaScript!

Lactose intolerance – Complications, Causes & Symptoms of Lactose intolerance

This post is also available in: हिन्दी (Hindi)

What is lactose intolerance? What is lactose malabsorption?

Complications, Causes & Symptoms of Lactose intolerance

What is lactose: lactose is the primary sugar present naturally in milk and milk products. It is thus known as milk sugar.

What is lactose malabsorption: it is the inability of the gut to fully digest lactose present in the food.

What is lactose intolerance: it is the inability of the body (gut) to tolerate undigested lactose present in the gut. This results in the development of symptoms of Lactose intolerance like diarrhea, gas, and bloating.

All cases of lactose malabsorption don’t have symptoms of Lactose intolerance and hence are not cases of lactose intolerance.

Even most of the people with lactose intolerance can consume some amount of lactose without developing symptoms of Lactose intolerance. The amount of lactose that can be tolerated varies from person to person.

Milk allergy: Lactose malabsorption or lactose intolerance is different from milk allergy which is an allergic reaction that occurs after consuming milk or milk products. The allergic reaction is the body’s immune response to protein present in milk which can be mild to severe or even life-threatening.

Fact to know: Lactose malabsorption is the inability to digest lactose present in food whereas, lactose intolerance is a condition where a person with lactose malabsorption develops complaints/symptoms of Lactose intolerance related to the gut.

What causes lactose intolerance?

Lactose malabsorption which is the inability to completely digest lactose occurs due to deficiency of an enzyme called lactase normally present in the small intestine.

Lactase is responsible to break down the complex sugar lactose into simpler components glucose and galactose which is then absorbed in the blood to be utilized by the body.

In the absence of lactase, the lactose is not broken down in the small intestine and thus passed forward into the large intestine. In the large intestine, the normal bacteria try to break it down resulting in production of fluid and gases which causes development of symptoms of lactose intolerance in some people.


Read More – What Tests Are Done for Kidney Stones Diagnosis?


So what could be the cause of lactase deficiency?

Lactase deficiency can be a result of two things:

1. Abnormality of the genes called as primary lactose intolerance

2. As a result of other problems of the gut called secondary lactose intolerance

Primary lactose intolerance:

Here a defect in the genes leads to a deficiency of the lactase enzyme production in the small intestine. This can affect a person in two ways:

1. Lactase nonpersistence: is the commonest cause of Lactose intolerance where the small intestine produces a low level of lactase after 1st year of life. In these people, lactase production gradually decrease with age, making digestion of the milk and its products difficult with increasing age. The symptoms of lactose intolerance may not appear before late childhood, early or mid-adulthood.

This condition is commonest in Asian and African populations affecting about 60-80% population. It is seen in about 44% population of Americans and 5-17% population of Europeans.

2. Congenital deficiency of lactase: rarely seen condition where the small intestine produces little or no lactase. This condition occurs when both the parents pass the same defected gene to the child.

Secondary lactose intolerance:

It is less common and is seen when a disease or immaturity of the gut leads to a temporary decrease in the production of the lactase.

1. Small intestine disease/condition: here conditions like infection, inflammation (like Crohn’s disease or celiac disease), medicines, surgery, or radiation therapy may damage the small intestine and temporarily decrease its ability to produce lactase enzyme. Successful treatment of the condition can lead to normal lactase production.

2. Premature birth: In some premature or preterm babies, the small intestine may not produce sufficient lactase during the early days after birth which results in lactose malabsorption. As the baby gets older the lactase production increases and becomes normal.

know more…

How common is lactose malabsorption?

The lactose malabsorption is a global condition spread in most parts of the world affecting 68% population, ie found in about every 2 people out of 3 in the world.

Not all people having lactose malabsorption develops lactose intolerance.

Who is more commonly affected by lactose malabsorption/lactose intolerance?

Lactose intolerance can affect anyone but is more common in people of Africa and Asia than people of western countries.

It is most commonly seen in people of Asia and Africa affecting most of the population. It is estimated in 57-83% of the population of the middle east. It is less common in western countries affecting 36% population of the USA and 28% population in Europe.

As these population groups are more likely to have lactose malabsorption, they are also more likely to develop lactose intolerance.

What are the symptoms of lactose intolerance?

lactose intolerance symptoms

People with lactose intolerance would develop symptoms within a few hours of having milk or milk products, or packaged/processed food with added lactose. The symptoms of Lactose intolerance could be:



Gas and flatulence

• Nausea

• Vomiting

• Abdominal Pain: cramp-like pain

• Growling sounds from the stomach

• Sometimes headache

The symptoms of Lactose intolerance may be mild to severe, depending on the amount of lactose consumed and the ability to produce lactase enzymes.

What other problems or complications lactose malabsorption could lead to?

Milk contains a good amount of protein and multiple nutrients like calcium and vitamins A, and D which are essential for bone growth and health. This makes milk and its products a crucial food item for the development and maintenance of bone.

Lactose malabsorption and intolerance may lead to a deficiency of these nutrients resulting in weakening of bones and even fractures.
The latest research printed in the journal Nutrients found that there is more risk of developing reduced bone density and fractures in cases of lactose intolerance than in people having less dairy intake or avoiding dairy.

These people can avoid such complications by changing their diet and replacing the source of required nutrients with other food items or supplements.

How lactose intolerance is diagnosed?

Doctor would ask about symptoms of Lactose intolerance and family history, do a physical examination, and may ask for some basic tests.

Doctor may advise to stop consuming milk and its products for some time and see for any change in symptoms of Lactose intolerance.

How lactose intolerance is treated?

The treatment of lactose intolerance depends on the cause.

Secondary lactose intolerance: If lactose tolerance is due to some condition or problem of the gut then the doctor would aim at treating the condition and recovering the normal production of lactase.


Breast cancer: One-dose radiotherapy ‘as effective as full course’

Breast cancer: One-dose radiotherapy ‘as effective as full course’

A single targeted dose of radiotherapy could be as effective at treating breast cancer as a full course, a long-term…

Coronavirus smell loss ‘different from cold and flu’

Coronavirus smell loss ‘different from cold and flu’

The loss of smell that can accompany coronavirus is unique and different from that experienced by someone with a bad…

Lancet Editor Spills the Beans

Lancet Editor Spills the Beans

Editors of The Lancet and the New England Journal of Medicine: Pharmaceutical Companies are so Financially Powerful They Pressure us…

Mother & Child

Guide to baby’s finger foods

Guide to baby’s finger foods

What are finger foods? Any solid food that can be eaten directly with hands rather than with utensils like a…

Parenting as a team

Parenting as a team

Raising your kid as a team Parenting is a rewarding feeling for both partners. However, along the way, it often…

Postpartum Period Symptoms and Complications

Postpartum Period Symptoms and Complications

What is the postpartum period? A postpartum period is the time interval during which a mother recovers after giving birth.…

Mind & Mental health

Generalized anxiety disorder (GAD)- Treatment

Generalized anxiety disorder (GAD)- Treatment

How generalized anxiety disorder (GAD) is treated? The treatment of generalized anxiety disorder is decided on the basis of severity…

Generalized anxiety disorder (GAD)- Diagnosis

Generalized anxiety disorder (GAD)- Diagnosis

How generalized anxiety disorder (GAD) is diagnosed? Before getting into the diagnosis details of GAD, learn about what is generalized…

Mindfulness: What is it and is it beneficial?

Mindfulness: What is it and is it beneficial?

Mindfulness – the practice of being present in the moment – has gained traction in the West over the last…