Lactose Tolerance Test: Purpose, Procedure & Results

A lactose tolerance test measures how well your body can process lactose, a type of sugar found in dairy products.

Normally, the body is able to process milk and other dairy products thanks to an enzyme in the intestines called lactase, which breaks down lactose during digestion.

However, some people’s levels of lactase are lower than normal. For these people, the lactose will persist in the intestines and ferment. This inability to digest lactose is referred to as lactose intolerance.

There are three kinds of tests that can be used to check lactose intolerance.

Hydrogen breath test

This test is the most common. During this test, your doctor will instruct you to drink a liquid solution containing lactose. You’ll then breathe into a balloon-like instrument at set intervals to determine how much hydrogen there is in your breath.

The more hydrogen you exhale, the more likely it is that your body is unable to process lactose.

Lactose tolerance test

Like the hydrogen breath test, this test requires you to drink a liquid with lactose. After 2 hours, your doctor will take a blood sample to measure how much glucose is in your blood.

If your blood glucose level doesn’t rise, this means that your body isn’t digesting or absorbing lactose.

Stool acidity test

This test is usually performed on infants or small children, as they’re not eligible for other tests. A physician will take a stool sample to see if lactose is breaking down properly in the system.

Fermenting lactose in the intestines (a sign of lactose intolerance) creates lactic acid, which can be detected in stool.

These tests may be performed in your physician’s office or in an outpatient laboratory.

Your physician may recommend this test if you have symptoms of lactose intolerance.

People with lactose intolerance often have the following symptoms after consuming dairy:

• nausea
• cramps
• diarrhea
• gas
• bloating

Lactose intolerance occurs more often in older adults and babies who are born prematurely.

If your doctor thinks you’re lactose intolerant, they may ask you to eliminate all dairy products from your diet for a short time to see if symptoms improve.

To prepare for the test, it’s a good idea to ask your doctor about which test you’ll be taking and to ask about any dietary restrictions. Your physician may ask that you not eat or drink for 8 hours before the test. Your physician may also restrict your exercise.

Make sure your provider knows about any other conditions you may have and any medications you’re currently taking. Some medications and foods can interfere with test results.

Smoking may also affect test results. If you’re a smoker, ask your doctor if you should abstain from tobacco prior to taking the test.

Hydrogen breath test

Before the test, your doctor will ask you to breathe into a balloon-like device to obtain a baseline, or typical, reading of how much hydrogen is in your breath after fasting.

Next, your doctor will have you drink a liquid that contains lactose and water. As your body digests the lactose, your doctor will ask you to breathe into the balloon-like device several times over a few hours to measure how much hydrogen is in your breath.

This is typically done in 15-minute intervals for approximately 2 to 3 hours. Increased levels of hydrogen in the breath indicate that the body isn’t properly breaking down or absorbing lactose.

Lactose tolerance test

For this test, your doctor will take a fasting blood sample to obtain a baseline reading of how much glucose is in your blood. Then, like with the hydrogen breath test, your doctor will have you drink a liquid with lactose.

As your body digests the lactose, it should break the lactose down into a simpler sugar called glucose. Your doctor will take blood samples several times over a few hours to measure how much glucose is in your blood.

Stool acidity test

This test is primarily for infants and young children. In this test, the doctor will have the infant or child drink a liquid with lactose. After waiting, the physician will take a stool sample.

Normally, stool isn’t acidic. However, if the body can’t break down lactose, lactic acid and other acids will appear in the stool.

Your doctor will discuss the results with you after the test. Remember, some results vary by doctor’s office and clinic.

Hydrogen breath test

A hydrogen breath test result that shows a rise in hydrogen of more than 12 parts per million over your original fasting test indicates lactose intolerance.

Lactose tolerance test

You may be lactose intolerant if blood glucose levels raise less than 20 milligrams per deciliter (mg/dL) within 2 hours of drinking the lactose solution.

Be sure to discuss what these results mean with your doctor and how you can manage your condition.

5 Low Lactose Dairy Products

Some dairy products, including hard cheeses and yogurt with probiotics, contain low levels of lactose. If you are lactose-intolerant, you may not experience symptoms when consuming them.

People with lactose intolerance often avoid eating dairy products in an attempt to avoid unwanted, uncomfortable, or embarrassing side effects.

However, not all dairy foods are high in lactose. Depending on the severity of your lactose intolerance, you may be able to consume some low lactose foods.

Lactose intolerance is a very common digestive problem. In fact, it affects around 65% of the world’s population. Interestingly, it’s most prevalent in Asia and South America, but much less common in parts of the Western world, including North America, Europe, and Australia.

Those who have it don’t have enough of an enzyme called lactase, found in the gut. Lactase is needed to break down lactose, the main sugar found in milk.

Without lactase, lactose can pass through the gut undigested and cause unpleasant symptoms, including:

• nausea
• pain
• gas
• bloating
• diarrhea

Fear of developing these symptoms can lead people with this condition to avoid foods that contain lactose, such as dairy products. However, this isn’t always necessary, as not all dairy foods contain enough lactose to cause problems for people with an intolerance.

In fact, it’s thought that many people with an intolerance can eat up to 12 grams of lactose a day without experiencing any symptoms. To put that in perspective, 12 grams is the amount found in 1 cup (230 ml) of milk.

Lactose intolerance effects everyone differently. For some people 12 grams may still be too much. It’s important to be aware of your own symptoms and how much lactose you can handle.

Also, remember that the 12 gram estimate is for the whole day. So if you have a glass of milk, then butter on your bread and cream in your coffee, you will be over the 12 grams, despite choosing low lactose options.

Certain dairy foods are naturally low in lactose. Below are 5 of them.

Butter is a high fat dairy product that’s made by churning cream or milk to separate its solid fat and liquid components.

The final product is around 80% fat, as the liquid part of milk, which contains all the lactose, is removed during processing.

This means that the lactose content of butter is really low. In fact, 3.5 ounces (100 grams) of butter contains only 0.1 grams of lactose.

Levels this low are unlikely to cause problems, even if you have an intolerance.

Butter made from fermented milk products and clarified butter products, such as ghee, contain even less lactose than regular butter.

So, unless you have another reason to avoid butter or need to use a large quantity, ditch the dairy-free spread.

Summary

Butter is a high fat dairy product that contains only trace amounts of lactose. This means it’s usually fine to include in your diet if you have lactose intolerance.

Cheese is made by adding bacteria or acid to milk and then separating the cheese curds that form from the whey.

Given that the lactose in milk is found in the whey, a lot of it is removed when cheese is being made.

However, the amount found in cheese can vary, and cheeses with the lowest amounts are the ones that have been aged the longest.

This is because the bacteria in cheese are able to break down some of the remaining lactose, lowering its content. The longer a cheese is aged, the more lactose the bacteria present is able to get rid of.

This means that aged, hard cheeses are often very low in lactose. For example, 3.5 ounces (100 grams) of cheddar cheese contains only trace amounts of it.

Cheeses that are low in lactose include Parmesan, Swiss, and cheddar. Moderate portions of these cheeses can often be tolerated by people with lactose intolerance.

Cheeses like pecorinos, made from sheep’s milk, are also naturally lower in lactose, as sheep’s milk has lower concentrations of lactose than cow’s milk.

Cheeses that tend to be higher in lactose include cheese spreads, soft cheeses like Brie or Camembert, cottage cheese, and mozzarella.

Even some higher lactose cheeses might not cause symptoms in small portions.

Summary

The amount of lactose can vary between different types of cheese. In general, cheeses that have been aged longer, such as cheddar, Parmesan, and Swiss, have low levels of lactose.

People with lactose intolerance often find yogurt much easier to digest than milk.

This is because most yogurts contain live bacteria that can help break down lactose, so your body has less to process on its own.

For example, one of the studies included in a 2014 review of papers on lactose digestion suggested that when eating yogurt, lactose intolerant people’s digestive tracts retained 60% less undigested lactose when eating yogurt than when consuming the same amount of milk.

According to the same study, yogurt also causes fewer symptoms, with only 20% of people reporting digestive distress after eating the yogurt, compared with 80% who struggled after drinking the milk.

It’s best to look for yogurts labeled “probiotic,” which means they contain live cultures of helpful bacteria. Yogurts that have been pasteurized, a process that kills the bacteria, may not be as well tolerated.

Additionally, full-fat and strained yogurts, like Greek and Greek-style yogurt, could be an even better choice for people with lactose intolerance.

This is because full-fat yogurts contain more fat and less lactose-laden whey than low-fat yogurts.

Greek and Greek-style yogurts are strained during processing. This removes even more of the whey, making them naturally much lower in lactose.

Summary

Lactose intolerant people often find yogurt easier to digest than milk. The best yogurt for people with lactose intolerance is a full-fat, probiotic yogurt that contains live bacterial cultures.

Choosing a protein powder can be tricky for those who are lactose intolerant. Protein powders are usually made from the proteins in milk whey, which is the lactose-containing liquid part of milk.

However, the amount of lactose found in whey protein powders can vary, depending on how the whey is processed.

There are three main types of whey protein powder:

• Whey concentrate: This contains up to 85% protein and a small amount of lactose.
• Whey isolate: This contains a higher concentration of protein and less lactose than whey protein concentrate.
• Whey hydrolysate: This contains a similar amount of lactose as whey concentrate, but some of the proteins in this powder have already been partially broken down.

The best choice for lactose sensitive individuals is whey isolate, which contains the lowest levels of lactose.

Nevertheless, the lactose content can vary considerably between brands, and most people have to experiment to see which protein powder brand works best for them.

Summary:

Dairy protein powders have already had some lactose removed. However, some types, such as whey isolates, have less lactose than others and may be a better choice for people who are lactose intolerant.

Kefir is a fermented beverage that’s traditionally made by adding “kefir grains” to animal milk.

Like yogurt, kefir grains contain live cultures of bacteria that help break down and digest the lactose in milk.

This means kefir may be better tolerated by people with lactose intolerance, when consumed in moderate quantities.

In fact, an older 2003 study found that, compared with milk, fermented dairy products like yogurt or kefir could reduce symptoms of intolerance by 54–71%.

Summary

Kefir is a fermented milk beverage. Like yogurt, the bacteria in kefir break down lactose, making it more digestible.

Brands that make popular dairy products will often offer low lactose alternatives, created by mixing lactase directly into the product in order to break down the lactose before you’ve even taken a bite.

Brands with entire lines of products that are lactose-free include Lactaid and Green Valley Creamery.

Plant-based dairy alternatives marketed to vegans are also great lactose-free options.

Contrary to popular belief, it’s not necessary for people with lactose intolerance to avoid all dairy products.

In fact, some dairy products — such as the ones discussed in this article — are naturally low in lactose.

In moderate and controlled amounts, they’re usually well tolerated. Some people may find that some of the foods listed above are harder on their digestive systems than others.

Also, remember to be mindful of portion sizes, and that more than one low-lactose food eaten together may add up to more lactose than your system can tolerate.

Through trial and error, as well as moderation, you can create a list of low lactose foods that are best for you.

How to understand that you can not drink milk?

These symptoms can be easily confused with manifestations of other conditions, which is why accurate diagnosis and going to the doctor is so important.

Tags:

Question answer

Popular

diet

longread

Getty Images

Lactose is a type of sugar found naturally in the milk of most mammals. Lactose intolerance is a condition that is caused by malabsorption of lactose.

Humans have an enzyme known as lactase, which is responsible for breaking down lactose during digestion. It is especially important for babies who need lactase to digest breast milk. However, as children get older, they usually produce less and less lactase.

By adulthood, up to 70 percent of people no longer produce enough lactase to properly digest the lactose in milk, resulting in symptoms when dairy products are consumed. This is especially true for people of non-European origin. Some people may develop lactose intolerance after surgery or due to gastrointestinal problems.

These are the most common signs of lactose intolerance.

ADVERTISING – CONTINUED BELOW

Abdominal pain and bloating

Abdominal pain and bloating are common symptoms of lactose intolerance in both children and adults. When the body cannot break down lactose, it passes through the intestines until it reaches the large intestine. Carbohydrates like lactose cannot be absorbed by the cells lining the colon, but they can be fermented and broken down by the bacteria living there. This fermentation causes the release of short chain fatty acids as well as hydrogen, methane and carbon dioxide gases.

The resulting increase in acids and gases can cause pain and spasms. Pain usually occurs around the navel and in the lower abdomen. The feeling of bloating is caused by an increase in the amount of water and gas in the colon, which causes the intestinal wall to stretch. Curiously, the degree of bloating and pain is not related to the amount of lactose ingested, but to the person’s sensitivity to the feeling of bloating. Thus, the frequency and severity of symptoms can vary significantly from person to person.

It is important to note that abdominal pain and bloating are common symptoms that can be caused by other causes such as overeating, other types of malabsorption, infections, medications, and other illnesses.

( See also: 5 reasons to drink milk every day.)

Diarrhea

Diarrhea is frequent and loose stools. Lactose intolerance causes diarrhea due to an increase in the volume of water in the colon, which increases the fluid content of the stool. It is more common in infants and young children than in adults.

In the colon, the microflora ferments lactose into short chain fatty acids and gases. Most, but not all, of these acids are reabsorbed back into the colon. The remaining acids and lactose increase the amount of water released by the body into the colon. Generally, more than 45 grams of carbohydrates must be present in the colon to cause diarrhea. For lactose, this is equivalent to three to four glasses (about 750 milliliters to one liter) of milk, provided the lactose is not digested before it reaches the colon.

However, not all carbohydrates that cause diarrhea come from lactose. In fact, in healthy people, between two and 20 percent of all carbohydrates consumed end up in the colon undigested. In addition, in addition to lactose intolerance, there are many other causes for diarrhea: dietary problems, other types of malabsorption, medication, infections, and inflammatory bowel disease.

Flatulence

Lactose fermentation in the colon increases the production of hydrogen, methane and carbon dioxide gases. In people with lactose intolerance, the colon microflora is very good at fermenting lactose into acids and gases. This causes more lactose to be fermented in the colon, further increasing flatulence.

The amount of gas produced can vary greatly from person to person due to differences in microflora efficiency as well as the rate of gas reabsorption by the colon. Interestingly, the gases produced during lactose fermentation are odorless. In fact, the smell of flatulence is due to the breakdown of proteins in the intestines, not carbohydrates.

( See also: How is casein different from whey protein?)

Constipation

Constipation is characterized by hard, infrequent stools, feeling of incomplete defecation, abdominal discomfort, bloating and excessive straining . It can be another sign of lactose intolerance, although it is a much rarer symptom than diarrhea. As bacteria in the colon ferment undigested lactose, they produce methane. Methane is believed to slow down the passage of food through the intestines, leading to constipation in some people.

So far, methane’s ability to cause constipation has only been studied in people with irritable bowel syndrome and bacterial overgrowth. Therefore, constipation is not usually associated with lactose intolerance, although it has been reported as a symptom.

Other causes of constipation include dehydration, lack of fiber in the diet, certain medications, irritable bowel syndrome, diabetes, hypothyroidism, Parkinson’s disease, and hemorrhoids.

( See also: Which is better – honey or sugar?)

What to do if you have these symptoms

Since the symptoms of lactose intolerance are quite common, it is important to get an accurate diagnosis before eliminating dairy products from your diet. Many people who think they are lactose intolerant because they have experienced similar symptoms actually digest lactose normally. Therefore, to make a final diagnosis, you should consult a doctor.

One way to diagnose lactose intolerance is the hydrogen breath test. It involves eating 50 grams of lactose and detecting elevated levels of hydrogen in the exhaled air, which is caused by bacteria that ferment lactose in the colon. Interestingly, up to 20 percent of people with lactose malabsorption will not test positive, and some people who test positive will have no symptoms at all. This is because not all people with malabsorption are lactose intolerant.

Treatment of lactose intolerance usually involves limiting or avoiding high-lactose foods such as milk, cream, and ice cream. However, people with lactose intolerance can often digest up to one glass (240 milliliters) of milk, especially when consumed in small portions throughout the day. This is equivalent to 12-15 grams of lactose. In addition, people often have a better tolerance for dairy products such as cottage cheese, cheese, and yogurt, so these foods can help meet calcium and protein needs without causing symptoms. The severity of manifestations varies from person to person, so it is important to find out how much dairy is right for you.

See also:

What is the difference between brown sugar and white sugar?

How useful are eggs in our diet?

Lactose intolerance: what is the cause and how to live without dairy products

Most people are used to putting everything they like into the grocery basket when they go to the grocery store. However, some do not have this opportunity. For example, people with food allergies, gluten or lactose intolerance.

What is lactose and what does it contain

Lactose is a disaccharide carbohydrate that the body digests with a substance called lactase. It breaks down lactose into two sugars: glucose and galactose, which, in turn, are easily absorbed by the blood.

The main function of lactose is to carry sugars and energy. It can also participate in the absorption of certain nutrients, that is, in their absorption by the body. It is found in animal milk and products containing it:

• butter,
• cheese,
• cream
• yogurt
• ice cream

1

Lactose-free curd 4.5%

120 g

66
rub

66.00
66.00

1

Ice cream, lactose-free

75 g

114
rub

114.00
114.00

1

Butter, lactose-free 72. 5%, 200 g

200 g

218
rub

218.00
218.00

We talked to experts about which bread is healthier and wrote here.

Many processed foods may also contain lactose. For example:

• cereals,
• pastries and baked goods (crackers, cakes, cookies, bread),
• sauces and salad dressings,
• protein shakes.

Causes and symptoms of lactose intolerance

Lactose intolerance occurs when the small intestine stops producing the right amount of lactase, an enzyme needed to digest lactose.

In this case, bacteria in the large intestine begin to interact with undigested lactose and cause unpleasant intolerance symptoms. These include:

• abdominal pain,
• diarrhea,
• nausea (sometimes vomiting),
• bloating,
• flatulence.

This can happen for various reasons. Risk groups include:

• People with genetic characteristics that cause congenital intolerance.
• Premature babies (cells that promote lactase production do not develop until after the third trimester).
• Elderly people (sometimes lactase production worsens with age).
• People with bowel problems such as intestinal infection, celiac disease, Crohn’s disease.
• People who have had radiation therapy for stomach cancer or have experienced bowel problems after chemotherapy.
• People of African, Asian, Hispanic, and Amerindian descent.

1

UHT lactose-free milk 1.5%, 970 ml

970 ml

136
rub

136.00
136. 00

1

Mozzarella cheese, lactose-free, 125 g

125 g

177
rub

177.00
177.00

Lactose-free diet

Unfortunately, there is no cure for lactose intolerance forever. There is lactase in tablet form that a doctor may prescribe to relieve symptoms. But a lactose-free diet can also help.

Among the products from the “dangerous” category, lactose-free:

• lactose-free special dairy products;
• soy milk, cheeses and yoghurts;
• rice, oats, almonds, hazelnuts, coconut, quinoa and potato milk.

Keep in mind that dairy products are a source of not only lactose, but also other important nutrients for the body. For example, magnesium, zinc, protein, vitamins A, D and B12, as well as calcium. This must be taken into account and compensate for the lack of important elements with the help of other products and supplements.

Myths and true claims about soy products we have collected in a separate article.

How to live when lactose is not allowed

Ekaterina Ryazanova told us about her personal experience of life with lactose intolerance.

“I developed lactose intolerance at the age of 11-12. Until this age, everything was in order, I could easily overeat any dairy products. But at some point, problems with the intestines and stomach began. Even from a small amount of milk, I quickly became ill. And then I could not understand what exactly the problem was. I had never come across anything like this before, my relatives didn’t have such a problem, and no one in the family suffered from food allergies and intolerances.

When your stomach hurts, the first thing parents say is “stop eating all sorts of filth”. This, of course, means chips, soda and other junk food. I remember that every time I suffered with my stomach in those years, my parents scolded me for malnutrition at school or in circles. After all, teenagers are not particularly fond of home-cooked meals: after school, you run to the tutor and to additional classes, and in between you sharpen either a bun from the supermarket or some snacks.

At that time, the arguments of parents about junk food sounded as logical as possible. But even when I began to control the diet, the problem did not disappear. On the contrary, homemade food was just as bad – cereal with milk every morning practically “killed” me. The same can be said about cereals, curds, cheeses. It never even occurred to me that the problem could be lactose.

My friend made me pay attention to milk. Her parents bought a coffee machine that made a variety of drinks, including amazing cocoa with milk or cream. We actively studied the unit, trying different drinks. And every time after that, I felt bad. From drinking coffee with milk to the state when the body began to “scream”, it could take only 20-30 minutes. That was the first time I thought about milk. I went online and researched the issue. I didn’t think that (lactose intolerance) was even possible. After that, by trial and error, I gradually began to study my body, its reaction to every dairy or supposedly dairy product.

I was born in a small town in the north. There were no special products, let alone lactose-free milk. But I am an experimenter. If I really wanted something dairy, for example, some cheese or dessert, I always took food home and there I already experimented on my own body. According to my own feelings, now I can safely say that most chocolates from supermarkets are prepared with powders. From dairy there are only beautiful words on the label. But I even like it. The same story with yogurt, cottage cheese and other products. Through trial and error, I have identified “safe food” for myself.

Intolerance has made me very selective. I can look at the packages for half an hour, standing at one shelf, and read the composition. I love manufacturers who do not hide lactose among other ingredients, but separately write about its presence. It is also encouraging that companies are finally paying attention to allergy sufferers. A huge number of special lactose-free products appeared in stores. So now I can easily find an alternative.

But you still can’t protect yourself completely. My biggest pain is restaurants and coffee shops. I often come across the fact that the staff neglects the requests and requests from allergy sufferers. To a direct question whether there is something dairy in the dish, the waiters can easily lie, and after that you will suffer.

1

Lactose-free milk 3.5-4.5%

500 g

102
rub

102.00
102. 00

1

Children’s cottage cheese, lactose-free 5%

100 g

45
rub

45.00
45.00

Read more about what a food allergy is and why people don’t eat because of it in a separate article.

Several times I felt ill right in restaurants, and I quarreled with the staff. During the conversation with the waiters, it turned out that the person considered my words a lie. I often heard that people often ask to remove unloved products from the dish, and the waiters politely nod and lie to the visitors: “Everything will be fine, you can do this, eat and don’t be afraid.” Be afraid! A couple of times I “burned myself” and now meticulously explain to each waiter what the problem is.

You have to keep an eye on the barista. In St. Petersburg, where I now live, there are a lot of small coffee shops, the culture of “coffee on the go” is developed. For the most part, such outlets have already acquired a decent list of alternative or lactose-free milk, but the barista can confuse, forget, not think. There was once a story when a barista started frothing lactose-free milk in a milk jug, where regular milk from another client remained. After I focused on this, I ran into rudeness. Even after explaining the reason, the barista refused to remake the drink. I just had to leave. Following me flew not the most flattering words, accusations of fastidiousness and show off.

Therefore, intolerance has affected almost all spheres of life. Even my friends have been taught not to offer me anything dairy. But for them and me it is perceived more positively. Of course, I can’t go with a friend to drink milkshakes or spend an evening in a gelateria, but I always manage to find a compromise.