Lactose intolerance It’s Symptoms, Causes and Prevention

Lactose Intolerance:

Lactose intolerance is a digestive disorder characterized by the body’s inability to fully digest lactose, a sugar found in milk and dairy products. This condition arises due to a deficiency of the enzyme lactase, which is typically produced in the small intestine. Lactase is responsible for breaking down lactose into simpler sugars, such as glucose and galactose, allowing for their absorption into the bloodstream.

Formula for Lactose:

Formula: C12H22O11

Melting point: 202.8C

Molar mass: 342.3 g/mol

Soluble in: Water and Ethanol

Classification: Disaccharide (Made up of glucose and galactose)


Lactose intolerance can cause a range of gastrointestinal symptoms, which often occur within 30 minutes to a few hours after consuming lactose-containing foods or beverages. Common symptoms include:

  1. Bloating: A sensation of fullness and discomfort in the abdomen.
  2. Diarrhea: Frequent and loose bowel movements.
  3. Gas: Excessive production of gas, leading to flatulence.
  4. Abdominal Cramps: Pain or discomfort in the abdominal area.
  5. Nausea: A queasy or nauseous feeling.

The severity of these symptoms can vary from person to person and is related to the level of lactase deficiency and the amount of lactose consumed

Reason behind lactose intolerance:

Normally, the peoples consumes dairy products which contain lactose when reaches to small intestine. The lactase enzyme is produced which breaks down the lactose molecule into Glucose and galactose. So, they absorbed from the intestinal linings.

While in some people with lactose intolerance, lactase enzyme is not produced so the lactose remains undigested and because of large mole it not absorbed either. So, it remains undigested and move towards the colon, the normal bacteria already present their act on it and symptoms and signs of lactose intolerance is shown.

It is very rarely but also found in babies which is inherited from both of their parents. This disorder is passed from generation to generation in a pattern of inheritance called autosomal recessive which means both parents have carries recessive genes.

The gene which is responsible for the lactose intolerance is the LCT gene, as you got older the function of this gene is reduced in about 65% of population.


Lactose intolerance is primarily caused by insufficient lactase enzyme production. There are three main types of lactose intolerance:

  1. Primary Lactose Intolerance: The most common form, often developing with age as the body produces less lactase.
  2. Secondary Lactose Intolerance: Occurs as a result of underlying medical conditions or treatments that damage the small intestine, such as celiac disease, Crohn’s disease, or certain medications.
  3. Congenital Lactose Intolerance: A rare genetic disorder present from birth, where little to no lactase is produced.
  4. Developmental lactase deficiency: A condition caused by pre-mature birth when the small intestine is under developed. But fortunately, it only lasts fo a short period of time after birth.

Risk factors

Increasing age:Lactose intolerance mainly appears with increasing age or in adult hood. This condition is normally uncommon in young ones and in babies.

Ethnicity: Lactose intolereance is mostly common in Africa, Asian, Hispanic and American Indian descendant. It also common in those who not regularly consume dairy products.

Pre-mature birth: Infants born pre-maturely also have low level of lactase because the cells responsible for lactase secretion in small intestine is not developed.  

Small intestine disease: Some Small intestine problems can also leads to lactose intolerance which include bacterial overgrowth, Crohn’s disease, and Celiac disease

Certain cancer treatment: if some body have gone through chemo or radiation therapy treatment of cancer for stomach or for intestinal linnings. The risk of developing lactose intolerance would be increase.

Table for lactose content in dairy products:

Product (Milk 1 cup)

Lactose Content (g)

Whole, 2%, 1%, Skim

9 to 14

Butter milk

9 to 12

Evaporated milk

24 to 28

How to make milk lactose free


                       Besides, the lactose intolerance there are major benefits of the milk which helps the body to grow stronger and increase immunity. There are many companies which sold lactose free milk, yogurt, cheese and butter. Mainly the leading company is Arla company.


                       Lactose is a disaccharide sugar molecule made up of Glucose and galactose. In lactose free products, we have split the lactose into glucose and galactose. While, in some advance countries they first filter the milk which in result filter about 40% of the lactose and them add the lactase enzyme which in result break the lactose molecule into two molecule glucose and galactose which is easily absorbed from small intestine.

The process of creating lactose-free milk is both fascinating and intricate.

While the level of protein and Calcium in this process is not disturbed.


Healthcare professionals can diagnose lactose intolerance through various methods, including:

  • Hydrogen Breath Test: Measures the amount of hydrogen in the breath after consuming a lactose solution.
  • Lactose Tolerance Test: Involves fasting, consuming a lactose solution, and monitoring blood glucose levels.
  • Stool Acidity Test: Measures the acidity of stool in response to lactose consumption.



Managing lactose intolerance typically involves dietary modifications, including:

Dietary Avoidance:

Limiting or eliminating dairy products from the diet.

  • Lactase Supplements: Taking lactase enzyme supplements before consuming dairy to aid digestion.
  • Lactose-Free Alternatives: Using lactose-free milk and dairy-free products made from sources like soy, almond, or coconut.
  • Gradual Introduction: Some individuals can tolerate small amounts of lactose, and gradual reintroduction may be possible.

Consulting a healthcare professional is crucial for a proper diagnosis and personalized guidance on managing lactose intolerance effectively. With the right strategies, most individuals with lactose intolerance can enjoy a comfortable and healthy lifestyle.


In conclusion, lactose intolerance is a prevalent condition with a clear scientific basis. Understanding the role of the lactase enzyme, the process of lactose absorption, and the mechanisms behind lactose intolerance is crucial for those affected by this condition. While lactose intolerance can present challenges, with proper management and dietary adjustments, individuals can continue to enjoy a comfortable and healthy lifestyle.


Q#1 Do Yogurt have lactose?

Yogurt is formed due to the fermentation of the sugar content in the milk. So, generally yogurt have very low content of lactose.

A cup of milk contains about 12g of lactose while 6 Ounce of yogurt contains only 4 grams of lactose, which falls in the limit of low lactose content food.

Q#2 Is it OK to be lactose intolerant?

Lactose intolerance is fairly common. Kids and teens are less likely to have it, but many people eventually become lactose intolerant in adulthood. Some health care providers view lactose intolerance as a normal human condition and not a disease or serious health problem.But it may cause some uncomfortable symptoms

Table of Contents

Leave a comment