Uncovering Food Sensitivities: The Role of Lactose Intolerance and Gluten Intolerance Tests

Uncovering Food Sensitivities: The Role of Lactose Intolerance and Gluten Intolerance Tests

Table of Contents

Lactose intolerance arises from the body's inability to properly digest lactose, a natural sugar found in milk and dairy products. Normally, the small intestine produces an enzyme called lactase, which breaks down lactose into simpler sugars for efficient absorption. However, in people with lactose intolerance, this enzyme is either insufficient or entirely absent, resulting in undigested lactose passing into the colon. The undigested lactose then interacts with gut bacteria, leading to the production of gases and causing symptoms like bloating, gas, diarrhea, and abdominal pain.

Similarly, gluten intolerance, also known as non-celiac gluten sensitivity, occurs when individuals experience adverse reactions after consuming gluten, a protein present in wheat, barley, and rye. Unlike celiac disease, which is an autoimmune disorder triggered by gluten ingestion, gluten intolerance does not involve an immune response attacking the intestine. However, it can still lead to uncomfortable symptoms like abdominal pain, bloating, diarrhea, fatigue, and headaches, which can greatly impact an individual's well-being.

Given the prevalence of lactose and gluten intolerance and the discomfort they cause, it becomes essential to identify these conditions accurately. Proper diagnosis not only confirms the presence of lactose or gluten intolerance but also aids in ruling out other gastrointestinal disorders with similar symptoms, thus preventing misdiagnosis. Equally important is the formulation of effective treatment plans that cater to the specific dietary needs of those affected, while ensuring that they continue to receive adequate nutrition.

Understanding Lactose Intolerance

Understanding Lactose Intolerance

Lactose intolerance is a digestive disorder characterized by the body's inability to digest lactose, a sugar found in milk and dairy products. The small intestine usually produces an enzyme called lactase, responsible for breaking down lactose into simpler sugars for absorption. However, people with lactose intolerance have insufficient or no lactase enzyme, leading to undigested lactose reaching the colon.

When lactose remains undigested in the colon, it can cause various uncomfortable symptoms, such as bloating, gas, diarrhea, and abdominal pain. These symptoms can vary in severity depending on the level of lactase deficiency and the amount of lactose consumed.

Lactose Intolerance Tests

Lactose intolerance is a common digestive disorder that affects a significant portion of the global population. To this end, healthcare professionals utilize a variety of lactose intolerance tests designed to assess lactase activity and confirm the presence and severity of lactose malabsorption.

Lactose intolerance tests play a crucial role in understanding an individual's ability to digest lactose, thus guiding the formulation of personalized treatment plans. Through these tests, lactose intolerance can be differentiated from other gastrointestinal conditions with similar symptoms and prevent misdiagnosis. By offering valuable insights into an individual's lactase activity and lactose malabsorption, these tests pave the way for tailored dietary adjustments and lifestyle modifications, ensuring that affected individuals can continue to enjoy a balanced and nutritious diet while avoiding discomfort and digestive distress.

There are several lactose intolerance tests available to help diagnose this condition:

Lactose Tolerance Test

Lactose Tolerance Test

The lactose tolerance test is a commonly used diagnostic tool to assess lactase activity and confirm lactose intolerance. The test involves a series of blood glucose measurements taken over several hours after the ingestion of a lactose-rich solution. Before the test, the individual is required to fast overnight to establish a baseline blood glucose level.

Once fasting blood glucose levels are recorded, the person drinks a beverage containing a substantial amount of lactose. Over the next few hours, blood samples are collected at regular intervals to monitor changes in blood glucose levels. In individuals with normal lactase activity, the lactose is efficiently broken down into glucose and galactose, leading to a rise in blood glucose levels.

On the other hand, individuals with lactose intolerance will experience minimal increases in blood glucose levels due to inadequate lactose digestion. The inability to efficiently metabolize lactose results in undigested lactose passing into the colon, where it interacts with gut bacteria and undergoes fermentation. This process leads to the production of gases, such as hydrogen and methane, which can be detected through other diagnostic tests like the hydrogen breath test.

Hydrogen Breath Test

The hydrogen breath test is a non-invasive and reliable method to assess lactose malabsorption. In this test, the individual drinks a lactose-containing beverage after an overnight fast. As the lactose reaches the colon, it interacts with gut bacteria and undergoes fermentation, producing gases such as hydrogen. The hydrogen gas is absorbed into the bloodstream and transported to the lungs, where it is exhaled in the breath.

During the test, breath samples are collected at regular intervals, typically every 15 to 30 minutes, for several hours. The concentration of hydrogen in the breath is measured, and elevated hydrogen levels indicate lactose malabsorption. This test is widely used due to its simplicity and non-invasive nature, making it particularly suitable for children and adults alike.

Stool Acidity Test

Stool Acidity Test

The stool acidity test is often employed for infants and young children suspected of having lactose intolerance. Since collecting breath samples can be challenging in young children, this test offers a practical alternative to assess lactose malabsorption. After the ingestion of lactose, undigested lactose in the colon ferments, leading to an increase in stool acidity.

To perform the test, a stool sample is collected after the child consumes a lactose-containing beverage. The acidity of the stool is measured, and elevated acidity levels suggest lactose malabsorption. The stool acidity test is a valuable tool for diagnosing lactose intolerance in younger populations, allowing for timely intervention and appropriate dietary adjustments.

Understanding Gluten Intolerance

Gluten intolerance, also known as non-celiac gluten sensitivity, is a condition where people experience adverse reactions after consuming gluten, a protein found in wheat, barley, and rye. Unlike celiac disease, which is an autoimmune disorder triggered by gluten ingestion, gluten intolerance does not involve an immune response.

People with gluten intolerance often report symptoms like abdominal pain, bloating, diarrhea, fatigue, and headaches after eating gluten-containing foods. The symptoms may be similar to those of celiac disease but are generally milder and do not cause the same long-term intestinal damage.

Gluten Intolerance Tests

Diagnosing gluten intolerance is a complex and challenging process, as there is no specific biomarker or definitive test to confirm the condition. Instead, healthcare professionals utilize a combination of tests and careful observation to assess gluten sensitivity accurately. These gluten intolerance tests play a crucial role in ruling out other gastrointestinal conditions, confirming the presence of gluten intolerance, and guiding the development of effective management strategies. However, medical professionals use a combination of tests and observations to make a diagnosis:

Symptom Monitoring and Medical History

The first step in diagnosing gluten intolerance involves a comprehensive evaluation of an individual's medical history and a careful analysis of the symptoms they are experiencing. Patients may present with a range of non-specific symptoms, such as digestive issues, fatigue, joint pain, and headaches, which can overlap with other conditions. By closely monitoring the patterns and characteristics of these symptoms, healthcare professionals can identify potential triggers related to gluten consumption.

During this process, patients are often asked to maintain a detailed food diary to track their daily dietary habits and any accompanying symptoms. This diary becomes a valuable tool in identifying possible correlations between gluten intake and symptom exacerbation. Additionally, healthcare providers may inquire about any family history of gluten-related disorders, as there is evidence suggesting a genetic predisposition to gluten intolerance.

Elimination Diet

The elimination diet is a crucial diagnostic method for identifying non-celiac gluten sensitivity. During this process, individuals are instructed to completely eliminate gluten-containing foods from their diet for a period, typically ranging from several weeks to a few months. By removing gluten from the diet, any adverse reactions or symptoms related to gluten consumption should diminish or disappear.

After the elimination phase, the next step is to reintroduce gluten-containing foods gradually. If symptoms reappear or worsen upon reintroduction, it suggests that gluten is the trigger, confirming the presence of gluten intolerance. The elimination diet is considered the gold standard for diagnosing gluten intolerance since it allows for direct observation of an individual's response to gluten elimination and reintroduction.

Celiac Disease Testing

Since celiac disease and gluten intolerance share some common symptoms, individuals suspected of having gluten intolerance should be tested for celiac disease to rule it out. Celiac disease is an autoimmune disorder triggered by gluten ingestion, causing damage to the lining of the small intestine. The most common celiac disease tests include serological tests, such as tissue transglutaminase (tTG) antibody tests and endomysial antibody (EMA) tests.

If celiac disease testing results are negative, but symptoms persist or improve during the elimination diet, it provides further support for a diagnosis of non-celiac gluten sensitivity. The combination of celiac disease testing and an elimination diet helps differentiate between celiac disease and gluten intolerance, ensuring that individuals receive appropriate care and management.

Importance of Lactose Intolerance and Gluten Intolerance Tests

Accurate Diagnosis and Proper Treatment

Accurate Diagnosis and Proper Treatment

The role of lactose intolerance and gluten intolerance tests is crucial in achieving accurate diagnoses. These tests help differentiate between various gastrointestinal conditions, ensuring that patients receive the appropriate treatment for their specific intolerance.

Avoiding Unnecessary Dietary Restrictions

By confirming lactose intolerance or gluten intolerance through testing, people can avoid unnecessary and potentially restrictive diets. Eliminating entire food groups from the diet can lead to nutritional deficiencies if not managed properly. With proper diagnosis, patients can modify their diets more effectively, targeting only the specific substances they need to avoid.

Preventing Misdiagnosis

Both lactose and gluten intolerance can present with symptoms similar to other gastrointestinal disorders. By conducting specific tests, healthcare professionals can prevent misdiagnoses and ensure that patients receive the most appropriate care.

Developing Effective Treatment Plans

Tailored Diet Plans

After the diagnosis of lactose or gluten intolerance, healthcare providers can create personalized diet plans for affected individuals. These plans will help patients avoid triggering foods while ensuring they still receive a balanced and nutritious diet.

Managing Symptoms and Improving Quality of Life

Properly diagnosing lactose or gluten intolerance allows healthcare professionals to address symptoms effectively. By managing symptoms, patients can experience an improved quality of life, reducing discomfort and enhancing overall well-being.

The Takeaway

Lactose intolerance and gluten intolerance are common digestive conditions that affect many people worldwide. Lactose intolerance is characterized by the body's inability to digest lactose, leading to uncomfortable symptoms. Gluten intolerance, on the other hand, involves adverse reactions to gluten consumption but does not cause the same immune response seen in celiac disease.

Various tests, such as the lactose tolerance test, hydrogen breath test, and stool acidity test, help diagnose lactose intolerance. For gluten intolerance, a combination of symptom monitoring, elimination diets, and celiac disease testing is used to arrive at a diagnosis. These tests play a vital role in accurate diagnosis, preventing misdiagnosis, and developing effective treatment plans that allow people to manage their conditions and improve their overall quality of life. 

If you suspect you may have lactose or gluten intolerance, consult with a healthcare professional to undergo appropriate testing and receive the necessary guidance for managing your condition effectively. For those stripped of time, you can try at-home test lactose and gluten intolerance kits such as those manufactured by AFIL

Watch AFIL test kits testimonial videos click here

advanced food intolerance labs kit


  1. Devulapalli, Chandra Sekhar. "Food intolerance in children." Tidsskrift for Den norske legeforening (2020).
  2. Ridefelt, Peter, and Lena D. Håkansson. "Lactose intolerance: lactose tolerance test versus genotyping." Scandinavian journal of gastroenterology 40.7 (2005): 822-826.
  3. Swagerty Jr, Daniel L., Anne D. Walling, and Robert M. Klein. "Lactose intolerance." American family physician 65.9 (2002): 1845-1851.
  4. Volta, Umberto, et al. "Serological tests in gluten sensitivity (nonceliac gluten intolerance)." Journal of clinical gastroenterology 46.8 (2012): 680-685.
  5. Unsworth, D. J., et al. "New immunofluorescent blood test for gluten sensitivity." Archives of Disease in Childhood 56.11 (1981): 864-868.

Author: Dr. Sony S. | Panel Expert, Medical Doctor Dr. Sony is known for her medical articles, written with in-depth detail and accuracy owing to her vast medical knowledge and thorough research of each article. She completed her degree with multiple scholarships from Guangzhou Medical University and is a board-certified Clinical Doctor. She is currently working as a Medical Officer in the emergency department of a renowned hospital and continues to publish numerous medical papers and articles. Dr. Sony continues to lead the way in medical breakthroughs, unparalleled by her high level of detail, knowledge and passion for discovering new sciences and innovative healthcare treatments.

Ready to get started on your health journey?

Take the Quiz