Lactose Intolerance Explained: Causes, Types, Symptoms, and Management

 

Lactose intolerance is a health condition that affects a significant portion of the global population. According to the National Institutes of Health, approximately 68% of the world’s population has a reduced capacity to digest lactose after infancy. This condition stems from inadequate production of lactase, an enzyme in the small intestine necessary to convert lactose into galactose and glucose for absorption into the bloodstream.

What Causes Lactose Intolerance?

Lactose intolerance causes are primarily attributed to insufficient production of lactase, the enzyme in the small intestine responsible for breaking down lactose. Individual variations in gut sensitivity also play a significant role.

 

Undigested foods reach the colon, interacting with distinct gut bacteria, forming the gut biome. These variations in the gut biome contribute to varying levels of lactose tolerance and diverse symptoms of lactose intolerance.

What are the Types of Lactose Intolerance?

Lactose intolerance can be categorised into three main types:

 

1. Primary Lactose Intolerance: This is the most common type and is genetically inherited. It usually manifests in adulthood as the body’s lactase production decreases after childhood. This reduction is a normal part of ageing for many people, particularly those of East Asian, West African, Arab, Jewish, Greek, and Italian descent.

 

2. Secondary Lactose Intolerance: This form results from injury or illness affecting the small intestine, where lactase is produced. Conditions such as Crohn’s disease, celiac disease, and gastroenteritis can damage the intestinal lining, leading to decreased lactase production. Treating the underlying condition in such cases may improve lactose intolerance.

 

3. Congenital Lactose Intolerance: This rare condition is present at birth due to a genetic mutation that results in little or no lactase production. It’s an autosomal recessive disorder, meaning both parents must pass on the defective gene. Infants with this condition cannot digest lactose from breast milk or formula and require a unique lactose-free formula.

What are the Symptoms of Lactose Intolerance?

The symptoms of lactose intolerance occur within a few hours of consuming lactose-containing beverages or foods. Symptom severity varies depending on how much lactose is consumed and the extent of the individual’s lactase deficiency.

 

Common symptoms include:

 

1. Bloating: Excess gas produced by fermentation of undigested lactose by bacteria in the colon.

2. Diarrhoea: Water retention in the colon due to undigested lactose, leading to loose stools.

3. Gas: Increased flatulence caused by the fermentation of lactose.

4. Abdominal Cramps: Pain and discomfort resulting from gas and bloating.

5. Nausea: Sometimes accompanied by vomiting, especially if a large amount of lactose is consumed.

How is Lactose Intolerance Diagnosed?

A lactose intolerance diagnosis involves a combination of medical history, dietary review, and specific tests. Key diagnostic methods include:

 

1. Lactose Tolerance Test: This test measures blood glucose levels after ingesting a lactose-rich beverage. If glucose levels do not rise, lactose has not been properly digested and absorbed.

 

2. Hydrogen Breath Test: This test measures hydrogen levels in the breath after consuming lactose. Usually, little hydrogen is detectable in the breath, but undigested lactose fermentation in the colon produces hydrogen, which is absorbed into the bloodstream and exhaled.

 

3. Stool Acidity Test: Primarily used for infants and young children, this testing for lactose intolerance involves measuring lactic acid and other short-chain fatty acids present in stool samples, which are products of undigested lactose fermentation.

How to Manage Lactose Intolerance?

Managing lactose intolerance primarily involves dietary adjustments to avoid symptoms while ensuring adequate nutrition. Effective strategies include:

 

1. Dietary Changes: Reducing or eliminating lactose-containing foods such as milk, cheese, yoghurt, and ice cream can help prevent symptoms. Individuals with lactose intolerance can often manage small quantities of lactose, so individual experimentation is necessary to determine tolerance levels.

 

2. Lactase Supplements: Over-the-counter lactase enzyme supplements can be taken before consuming lactose-containing foods. These supplements provide the enzyme needed to digest lactose, reducing the likelihood of symptoms.

 

3. Lactose-Free Products: Lactose-free dairy products are widely available and provide the same nutrients as regular dairy without causing symptoms. These include lactose-free milk, cheese, and yoghurt.

 

4. Alternative Nutritional Sources: Adequate calcium and vitamin D intake is crucial, as dairy is a primary source of these nutrients. Non-dairy calcium sources include leafy green vegetables, fortified plant-based milk (almond, soy, or rice), tofu, and almonds. Exposure to sunlight, fortified foods, and supplements are sources of vitamin D when necessary.

 

Lactose intolerance is a manageable condition with the proper knowledge and strategies. Understanding the causes, symptoms, and management options helps make informed choices about diet and lifestyle, ensuring one’s health and well-being. If lactose intolerance is suspected, it is essential to consult a healthcare professional and book a food tolerance test with Dr Lal PathLabs for an accurate diagnosis and personalised advice.

FAQs

1. What are the four stages of lactose intolerance?

The stages of lactose intolerance are:
1. Lactose ingestion,
2. Lactase deficiency,
3. Lactose fermentation in the colon,
4. Symptom manifestation (bloating, diarrhoea, gas).

2. What are the five symptoms of lactose intolerance?

Symptoms include bloating, diarrhoea, gas, abdominal cramps, and nausea.