Lactose Intolerance: Understanding the Digestive Disorder and Its Treatment

July 2, 2024

Lactose intolerance is a common digestive disorder that affects millions of people worldwide. It occurs when the body is unable to properly digest lactose, a sugar found in milk and dairy products. This condition can lead to uncomfortable symptoms and significantly impact daily life. Understanding the causes, symptoms, and treatments of lactose intolerance is essential for managing this condition effectively.

Causes of Lactose Intolerance

Lactase Deficiency

The primary cause of lactose intolerance is a deficiency in lactase, the enzyme responsible for breaking down lactose in the small intestine. Without sufficient lactase, lactose remains undigested and passes into the colon, where it is fermented by bacteria, leading to the production of gas and other symptoms.

Genetic Factors

Lactose intolerance is often inherited and is more common in certain ethnic groups, including people of Asian, African, Native American, and Mediterranean descent. Genetic factors influence the production of lactase, and many individuals experience a decline in lactase levels as they age.

Secondary Lactose Intolerance

Secondary lactose intolerance can occur due to illnesses or conditions that damage the small intestine, such as celiac disease, Crohn’s disease, or gastrointestinal infections. These conditions can reduce lactase production temporarily or permanently, depending on the severity and duration of the underlying issue.

Symptoms of Lactose Intolerance

Gastrointestinal Symptoms

Common symptoms of lactose intolerance include bloating, gas, diarrhea, and abdominal pain. These symptoms typically occur within 30 minutes to two hours after consuming lactose-containing foods or beverages. The severity of symptoms varies depending on the amount of lactose ingested and the individual’s level of lactase deficiency.

Additional Symptoms

In some cases, lactose intolerance can cause nausea and, less frequently, vomiting. These symptoms are less common but can occur in individuals with severe lactose intolerance.

Diagnosing Lactose Intolerance

Lactose Tolerance Test

A lactose tolerance test measures the body’s reaction to a dose of lactose. After fasting, the individual consumes a lactose-rich beverage and blood samples are taken at intervals to measure glucose levels. A rise in blood glucose indicates proper digestion of lactose, while little or no change suggests lactose intolerance.

Hydrogen Breath Test

The hydrogen breath test is another common method for diagnosing lactose intolerance. After consuming a lactose-rich beverage, the individual breathes into a device that measures hydrogen levels. Higher than normal hydrogen levels indicate that lactose is not being properly digested and is being fermented by bacteria in the colon.

Stool Acidity Test

For infants and young children, a stool acidity test may be used. This test measures the amount of lactic acid and other acids in the stool, which can indicate lactose malabsorption.

Treatment and Management of Lactose Intolerance

Dietary Adjustments

The most effective way to manage lactose intolerance is to adjust the diet to limit or avoid lactose-containing foods and beverages. Many individuals can tolerate small amounts of lactose, so identifying and managing the threshold level is crucial.

  • Lactose-Free and Low-Lactose Products: There are numerous lactose-free and low-lactose alternatives available, including lactose-free milk, yogurt, and cheese. These products provide the nutritional benefits of dairy without causing symptoms.
  • Plant-Based Alternatives: Plant-based milk and dairy alternatives, such as almond milk, soy milk, and coconut milk, are naturally lactose-free and can be included in the diet.

Lactase Supplements

Lactase enzyme supplements are available over-the-counter and can be taken before consuming lactose-containing foods to help digest lactose. These supplements can be particularly useful for individuals who wish to enjoy dairy products occasionally without experiencing symptoms.


Probiotics, which are beneficial bacteria that support gut health, may help improve lactose digestion. Certain strains of probiotics have been shown to reduce symptoms of lactose intolerance, particularly in individuals with mild to moderate intolerance.

Gradual Introduction

For some people, gradually introducing small amounts of lactose into the diet can help increase tolerance over time. This approach should be done under the guidance of a healthcare professional to avoid severe symptoms.


Lactose intolerance is a manageable condition with a combination of dietary adjustments, lactase supplements, and, in some cases, probiotics. Understanding the causes and symptoms of lactose intolerance is crucial for effective management and maintaining a healthy, balanced diet. Consulting with a healthcare provider for personalized advice and guidance can help individuals with lactose intolerance lead a comfortable and symptom-free life.