Lactose Intolerance

Order the lactose intolerance tests to evaluate if you are intolerant to dairy and products containing lactose from Ulta Lab Tests. Learn about your health today!


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The presence of reducing substances is useful in the diagnosis of abnormalities in carbohydrate metabolism, i.e., sucrose and lactase. The unabsorbed sugars in stool are measured as reducing substances.


7 Frequently Asked Questions About Lactose Intolerance Tests

Stomachaches, gas, loose stools - there are plenty of unfortunate consequences of lactose intolerance.

But how do you know if you're actually lactose intolerant? What if you're just prone to having stomach issues?

If you're experiencing chronic digestive discomfort, then you should consider lactose intolerance tests. Especially if you feel discomfort after ingesting a lot of dairy.

Give yourself the best chance for comfort. Sometimes, taking a test can do just that.

So keep reading for seven frequently asked questions about lactose intolerance tests. Afterward, you'll be ready to change your lifestyle and diet for the better.

What is Lactose Intolerance?

Lactose intolerance refers to a body's inability to digest lactose, a natural sugar in dairy products. When a lactose-intolerant person ingests lactose, the lactose will move through the digestive system without proper digestion.

Is Lactose Intolerance an Allergy?

No. Allergies are defined by an immune system's misguided reaction to typically harmless substances. A severe allergic reaction can cause anaphylactic shock, which can turn lethal.

Instead, lactose intolerance can be extremely uncomfortable. But while it causes discomfort, it usually does not result in serious medical consequences.

Who is at Higher Risk for Lactose Intolerance?

The most defining factor for lactose intolerance is ethnicity. Those of Asian, Hispanic, African, and Native American descent are at higher risk of lactose intolerance than others.

A less common factor is premature birth. That's because the small intestine typically develops cells that produce lactase late into the third trimester. But babies born before that period don't usually have the chance to develop enough of those cells.

However, these are only risk factors, not risk guarantees. It's possible for an individual to meet all these criteria but not have lactose intolerance. Also, people can also meet none of these criteria and still develop lactose intolerance.

What Causes Lactose Intolerance?

The body's inability to digest lactose starts with the small intestine. Once again, the small intestine has the responsibility of developing cells that produce lactase. Lactase is necessary for breaking down lactose.

We've already covered demographics that are at higher risk for lactose intolerance. But lactose intolerance can also be inherited from a parent. For that reason, lactose intolerance very commonly runs in families.

But sometimes, people can experience brief periods of lactose intolerance without experiencing it chronically. That's because conditions like short-term illness, especially stomach illnesses, can cause the small intestine to stop developing lactase-producing cells.

However, long-term illnesses can also cause long-term lactose intolerance. In these cases, lactose intolerance typically lasts as long as the illness does. However, long-term illnesses may persist for life.

What are the Symptoms of Lactose Intolerance?

When the body cannot break down lactose, individuals can suffer a variety of gastrointestinal problems. Some of these symptoms include:

  • Bloating
  • Gas
  • Diarrhea
  • Nausea
  • Vomiting
  • Stomach cramps
  • Stomachaches

These symptoms appear quite quickly after lactose ingestion. For that reason, it can be easy to tell whether someone has lactose intolerance.

However, some people are less lactose intolerant than others and are comfortable ingesting a small amount of dairy and milk. Not only that, but some milk and dairy products are naturally low in lactose.

Butter, probiotic yogurt, and hard cheeses are all low in lactose. Many lactose-intolerant people can digest these products with no problem. There may be individuals that are extremely lactose intolerant, but these foods are generally safe for most lactose-intolerant people to consume.

Are there Lactose Intolerance Lab Tests?

Yes! Although it can be easy to tell whether someone is lactose intolerant, lactose intolerance tests still have additional benefits.

This test won't only let you know if you're lactose intolerant. It will also let you know how well your body digests lactose. You can figure out the severity of your tolerance with some simple tests.

There are three types of lactose intolerance testing. The first is the more common stool test and is available to order directly at Ulta Lab Tests. The stool test is conducted as follows:

  1. 10g of fresh stool is collected in a plastic, leak-proof container.
  2. Adults older children can pass their fecal samples into plastic wrap stretched loosely over the toilet bowl.
  3. Unabsorbed lactose in stool samples could indicate a variety of metabolic abnormalities. One of these abnormalities is the lack of lactase.

The hydrogen breath test is conducted as follows:

  1. Patient breathes into a container
  2. They then drink a lactose-containing liquid
  3. Throughout this time, testers will test hydrogen levels throughout this process
  4. If hydrogen levels increase after ingesting lactose, then that's an indication of lactose intolerance

The blood test is conducted as follows:

  1. A series of blood samples are taken before and after patient ingests lactose.
  2. If there is too much glucose in your blood, then lactose has not broken down enough, indicating lactose intolerance

Is there a Cure for Lactose Intolerance?

There is no "cure" for lactose intolerance, but there are many ways to make the condition more tolerable. Such methods include:

  • Limiting milk/dairy intake
  • Consuming milk/dairy products formulated to be lactose-free
  • Taking tablets/powders that contain lactase when ingesting dairy
  • Taking probiotics to improve digestive response

For most people, lactose intolerance does not severely impact the quality of their life. The most serious treatment is eliminating milk and dairy altogether, which is getting easier due to the increase in milk/dairy alternative products.

Sign up for Lactose Intolerance Tests Today!

At Ulta Lab Tests, we offer highly accurate and reliable tests - including lactose intolerance tests. Not only that, but we provide confidential results and don't require insurance or physician referrals. To top it off, our testing service is the most affordable out there.

After you get tested, your confidential results will be delivered online to your private patient portal within 24 to 48 hours for most tests. So take control over your health by ordering a lactose intolerance test now.

Lactose is a type of sugar found in mammal milk. Lactose intolerance is a condition where the ability of the body to digest lactose is reduced. Lactose is present in breast milk, yogurt, cheese, butter, and ice cream. Individuals who are lactose intolerant might develop certain abdominal symptoms within 30 minutes to 2 hours of consuming dairy products. The severity of symptoms may vary from individual to individual and depends on the type and amount of dairy products consumed.  

Lactose is a sugar that has a complex structure known as a disaccharide. Before lactose could be absorbed and used by the body, it needs to be broken down into simple sugars such as glucose and galactose – both monosaccharides. This digestion process is initiated by lactase – an enzyme that’s produced in the cell linings of the small intestine. If a person doesn’t produce enough lactase, the undigested lactose is passed through the small intestine into the large intestine. Bacteria in the large intestine will break down the lactose, producing excess lactic acid and hydrogen and, thus, inhibiting water and salt absorption.  This can result in abdominal cramps and diarrhea. 

The lactase enzyme is produced in developing babies during pregnancy and peaks near birth. Most all babies are able to digest milk though some premature infants may have some intolerance.  Normal production of lactase track’s an infant’s milk consumption as breast milk is the primary source of nutrition. The lactase levels in babies decrease after the first couple of years and continue to decrease with age.  But 35% of adults across the world can produce lactase throughout adulthood and could digest lactose with no symptoms. This condition is known as lactase persistence or LP and is common to specific ethnicities and races. Northern European people have the highest rate of LP and the lowest incidence of lactose intolerance. Native American and Asian adults have the highest incidence of lactose intolerance. 

Ethnic Group                % Of Lactose Intolerance in Adults 

  • Southeast Asians         98% 
  • Indian Adults                50% 
  • Asian Americans          90% 
  • African Americans      79% 
  • Mexican Americans     55% 
  • Northern Europeans   05% 

Types of Lactose Intolerance 

There are a number of other conditions and diseases that can cause a secondary form of lactose intolerance in addition to the natural intolerance associated with increasing age. Damage to the lining of the small intestines can lead to the inability to absorb lactose in a beneficial manner. Radiation therapy, celiac disease, inflammatory bowel disease (or IBS), chemotherapy, overgrowth of bacteria or infections caused by parasites, all may result in a decreased lactose digestion.  Stomach contents in the small intestines move much quicker than normal in some people. These people can suffer from the condition because of insufficient time to digest lactose. Lactase deficiency is grouped into three clinical syndromes – alactasia (or congenital lactase deficiency), hypolactasia (or primary adult lactase deficiency), and secondary lactase deficiency. 

Congenital Lactase Deficiency 

There are two genes linked to the production of the lactase enzyme. The LCT gene is responsible for the production of lactase, and the MCM6 gene is responsible for controlling the expression of the LCT gene. Mutations to the LCT gene may result in congenital lactase deficiency. It’s an autosomal inheritance that requires one mutated gene from each parent. Congenital lactase deficiency is a rare form of lactose intolerance that begins at birth. It may severely inhibit the baby’s ability to digest milk and milk-based formulas. 

Primary Adult Lactase Deficiency 

Primary adult lactase deficiency is a common form of lactose intolerance. It is linked to the decreased production of lactase in adults. The affected individual will be less likely to suitably digest lactose due to this condition. The intensity of the condition may vary depending on the ethnic and racial makeup. The MCM6 gene regulates the functions of the LCT gene. This will result in a decrease in lactase production over time (or nonpersistence). Northern European people, primarily, have an inherited MCM6 gene mutation that could lead to persistence in digesting lactose in adulthood.  People who don’t have this mutation will lose the ability to produce lactase as they grow old that may result in lactose intolerance in the long run.  

Secondary Lactose Intolerance 

The symptoms of lactose intolerance are also prevalent in other gastrointestinal conditions, usually caused by a disease or damage to the lining of the small intestine.  This can lead to the loss of lactase.  Your healthcare provider can perform certain tests to determine the various conditions that have similar symptoms.  Different conditions have different prognoses and treatments. Treating the primary condition can reverse the secondary lactose intolerance condition.

Here are some other conditions that have similar symptoms: 

  • Crohn’s disease 
  • Celiac sprue 
  • Whipple disease 
  • Bacterial growth syndrome 
  • Short bowel syndrome 
  • AIDS 
  • Tropical sprue 
  • Giardia infections 
  • Cystic fibrosis 
  • Radiation or chemotherapy 
  • Zollinger Ellison syndrome 

Symptoms of Lactose Intolerance

The symptoms of lactose intolerance occur primarily due to undigested lactose reaching the large intestines. Extra fluids will be drawn into the large intestines where bacteria will break down the lactose. It will result in the excess production of hydrogen gas and lactic acid. This may cause: 

  • Abdominal bloating 
  • Abdominal cramps and pain 
  • Nausea 
  • Diarrhea 
  • Flatulence and excessive gas 

The severity of symptoms will vary depending on the individual and the amount and type of dairy products ingested. Many people who suffer from the condition can successfully consume small amounts of dairy products with few or no symptoms at all.  Some people confuse lactose intolerance with an allergy to cow’s milk.  Milk allergy happens due to a reaction by the immune system. The allergy is directed against a protein in the milk but not sugar.  A person who has a milk allergy can suffer mild to severe symptoms, and even life-threatening reactions, within minutes to hours soon after consuming cow’s milk.  They can also experience hives and wheezing in addition to the other symptoms associated with the allergy.  Lactose intolerance affects more adults than children.  On the contrary, milk allergies are much more common in young kids who tend to outgrow the allergy with aging.  

Laboratory Tests for Lactose Intolerance 

The goal of lab tests for lactose intolerance is to diagnose the condition and distinguish it from other conditions with similar symptoms.

  • Hydrogen breath test – This is the most effective lab test to diagnose lactose intolerance at this time.  Breath samples of the patient are taken before (as the baseline) and at times after the person drinks a fluid with lactose.  Hydrogen is produced in excess in the large intestines in a person who suffers from lactose intolerance.  This hydrogen moves to the circulation system and eventually is exhaled by the lungs.  Increased levels of hydrogen in the breath over time is a strong indicator of a lactose intolerance condition.  Lactose tolerance blood test – Blood samples are tested for glucose at different times – once an oral dose of lactose is given to the person. If the glucose level in the blood doesn’t rise, lactose intolerance may be present.  This test is rarely ordered in a clinical environment. 
  • Stool Acidity pH test – This test is usually performed on infants and kids who cannot undergo other tests.  Stools will become acidic when lactose intolerance is present.   

 Rarely ordered clinical tests for lactose intolerance include:

  • Genetic testing of the lactase or LCT gene 
  • Biopsy of a sample from the small intestine to diagnose lactase activity 

The aforementioned laboratory tests will be ordered by your health care provider to help diagnose whether you are suffering from lactose intolerance.