About all

Can lactose intolerance develop later in life: Mayo Clinic Q and A: Lactose Intolerance Can Develop at Any Age

Mayo Clinic Q and A: Lactose Intolerance Can Develop at Any Age

  • By

    Liza Torborg

DEAR MAYO CLINIC: What would cause someone to become lactose-intolerant later in life? I’m in my 40s and have never had an issue with dairy, but, now, I can’t seem to have it without problems. Do I need to see a doctor to be tested for allergies, or should I just avoid dairy?

ANSWER: Lactose intolerance isn’t a true allergy, and it can develop at any age. In some people, lactose intolerance may be triggered by another medical condition, such as Crohn’s disease. In others, it develops without a specific underlying cause. It would be a good idea to have your condition evaluated by your doctor to confirm that what you’re dealing with truly is lactose intolerance.

Lactose intolerance results from a problem with the carbohydrate lactose, a type of sugar found in dairy products. When you eat or drink dairy products, enzymes in your small intestine digest lactose, so the body can make energy. In people with lactose intolerance, a certain enzyme, called lactase, is missing from the body. When those people eat dairy products, the body has no way to break down the lactose. This leads to fermentation of the sugar in the intestines and triggers symptoms, such as diarrhea, nausea, abdominal cramps, bloating and gas.

Sometimes, lactose intolerance develops when the small intestine’s production of lactase decreases after an illness, injury or surgery involving the small intestine. This is called secondary lactose intolerance. Among the diseases associated with this kind of lactose intolerance are celiac disease, bacterial overgrowth and Crohn’s disease. Treatment of the underlying disorder may restore lactase levels and improve symptoms.

More common than secondary lactose intolerance is primary lactose intolerance. People who develop primary lactose intolerance start life making normal levels of lactase — a necessity for infants, who get all their nutrition from milk. As children replace milk with other foods, lactase production normally decreases. It stays high enough, though, to digest the amount of dairy in a typical adult diet. In primary lactose intolerance, lactase production declines below normal at some point for reasons that are unclear. The low amount of lactase then makes milk products difficult to digest and leads to lactose intolerance symptoms.

Your doctor can confirm a diagnosis of lactose intolerance with a clinical test. One that’s often used is a lactose tolerance test. It assesses your body’s reaction to a dose of lactose. After you consume a drink containing lactose, a sample of your blood is taken to measure glucose levels. If your glucose level does not rise, it means your body isn’t properly digesting and absorbing the lactose.

Alternatively, another test called the hydrogen breath test may be used. This test also requires you to consume a drink that contains high levels of lactose. Your doctor next measures the amount of hydrogen in your breath. Normally, very little hydrogen is detectable. However, if your body doesn’t digest the lactose, the fermentation reaction in your colon releases hydrogen and other gases. Your intestines absorb those gases, and you exhale them. Larger-than-normal amounts of hydrogen measured during this test are a sign that your body isn’t fully digesting and absorbing lactose.

If you have lactose intolerance, there isn’t a way to cure it. The most effective way for people with lactose intolerance to get relief from symptoms is to lower the amount of dairy products they eat. You may be able to use dairy products that have reduced levels of lactose or are lactose-free. Some people who have lactose intolerance benefit from taking lactase enzyme supplements, as well.

If test results do not point to lactose intolerance, your doctor may recommend additional tests to check for another condition that could be causing your symptoms, such as a milk allergy, intestinal disorders or other problems within your digestive tract. — Dr. Rohit Divekar, Allergic Diseases, Mayo Clinic, Rochester, Minnesota

Related articles

Mayo Clinic Minute: What is a breast medicine specialist?

Many people think that a breast health specialist only treats cancer, but the truth is that these doctors handle a wide range of breast-related conditions.
Dr. …

By Sonya Goins • July 7, 2023

Mayo Clinic Q and A: Proper posture and body alignment

DEAR MAYO CLINIC: My grandmother lives with me, and she is always nagging me to “stand up straight” and “put your shoulders back.” She says good …

By Mayo Clinic Staff • July 7, 2023

Can You Get It as You Get Older?

Written by Susan Bernstein

Do you get gas, bloating, or even diarrhea after you eat dairy foods? You may be lactose intolerant. This is when you can’t digest lactose, the type of sugar found in dairy products.

Lactose intolerance isn’t a serious health condition, but symptoms can be uncomfortable. You may have stomach upset or gas about 30 minutes to 2 hours after you eat or drink any dairy food.

Lactose intolerance is caused by low levels of lactase, an enzyme that helps you digest lactose in dairy foods, says Laura Acosta, a registered dietitian at the University of Florida in Gainesville.

“Some people are able to tolerate lactose throughout their lives, but others become more lactose intolerant as they age,” usually caused by your genes, she says. “Some people stop producing lactase, or produce less of it, as they reach adulthood and beyond.”

Lactose intolerance is more common among people of Southeast Asian, East Asian, West African, Native American, Hispanic, or Italian ancestry because they’re more likely to carry the gene mutation that causes the condition, says Vijaya Surampudi, MD, assistant professor of medicine at the University of California, Los Angeles.

“We have the highest amounts of lactase when we are young because as babies, we feed on milk. But we often make less and less lactase as we age,” she says. “About 65% of people may experience lactose intolerance at some point in their lives.”

There’s a wide range of lactose intolerance, with some people having no tolerance for dairy, while others can manage to digest foods like hard cheeses or yogurt, she says.

It’s fairly common to notice the signs of lactose intolerance appear as you get older, says Christine Lee, MD, a gastroenterologist at Cleveland Clinic in Ohio.

“This enzyme production can decrease over time in some people, so most people can experience some degree of lactose intolerance as they get older,” Lee says. You can also become lactose intolerant if you have an illness, infection, or take a medication that affects the bowels or intestines.

These conditions can also cause you to develop lactose intolerance later in life:

  • Crohn’s disease
  • Ulcerative colitis (UC)
  • Celiac disease
  • Injury or trauma to your small intestines

Foods. Any dairy foods or drinks can have lactose, so read food labels carefully. These foods or ingredients may trigger symptoms:

  • Cheese
  • Whey
  • Milk by-products
  • Dry milk
  • Butter
  • Curds
  • Ice cream
  • Heavy cream
  • Cottage cheese
  • Cheese spreads
  • Yogurt

Look for milk in ingredients lists in baked goods, chocolate candies, sauces, instant mashed potatoes, pancakes, or milk-based meal replacement or protein shakes. Even non-dairy coffee creamer or whipped toppings may contain some lactose.

Medications. Some medications like birth control pills or antacid tablets also contain lactose, but these may only cause symptoms in people with severe lactose intolerance. Check the labels of your prescription or OTC medications to see if they contain lactose. Ask your doctor or pharmacist if it’s OK for you to take them.

You may not have to give up all the dairy foods you enjoy if you develop lactose intolerance.

Some people with lactose intolerance may be able to eat or drink small amounts of dairy or switch to skim milk and have fewer symptoms. Some people can eat yogurt because it contains live bacteria cultures that help you produce the lactase enzyme to break down lactose.

“Cheese actually has very little lactose. In general, the harder the cheese, the less lactose it has. So many people with lactose intolerance can still tolerate cheese like Parmesan and Swiss in small amounts. This depends on an individual’s sensitivity,” Acosta says.

Talk to your doctor to identify what’s causing your lactose intolerance so you can make the right changes to your diet, Lee says.

“If it’s due to decreased production of lactase, then you can choose to take lactase tablets or drops, enzymes sold in most grocery stores without a prescription, or buy lactose-free milk products,” she says. Supplements are taken before a meal with dairy to help you digest the lactose.

If your lactose intolerance is due to a bowel disease or other health conditions, treat that illness first, she adds. “Always play it safe and discuss your symptoms with your physician.” Unexplained weight loss, bleeding, anemia, nausea, or vomiting may be signs of a more serious medical condition, not just lactose intolerance, she says.

As you age, you still need to get enough calcium even if you develop lactose intolerance. Calcium helps you maintain strong bones and teeth, and healthy muscles and nerves.

“There are many calcium-rich foods people can eat if they’re avoiding lactose,” says Allie Wergin, a registered dietitian/nutritionist with Mayo Clinic Health System. “These include lactose-free dairy products like Lactaid or Dairy Ease milks, where the lactose is predigested or hydrolyzed. This means the milk protein has already been broken down and is easier to digest.”

Other foods that are good sources of calcium, according to Wergin:

  • Calcium-fortified cereals and fruit juices
  • Tofu prepared using calcium sulfate
  • Canned salmon or sardines with bones
  • Plant-based soy, almond, oat, or rice milks
  • Leafy green vegetables like spinach, kale, bok choy, or collard greens
  • Broccoli
  • Almonds
  • Beans like garbanzo, kidney, or navy

“We recommend that you get calcium through your diet. There are different calcium supplements, including calcium carbonate, which is best absorbed if you take it with food, and calcium citrate, which you can take with or without food,” Surampudi says. Only take a calcium supplement if your doctor says you need one, she says.

Top Picks

Lactose intolerance | Symptoms, complications, diagnosis and treatment

People with lactose intolerance are unable to fully digest the lactose in milk. As a result, they develop diarrhea, gas, and bloating after eating or consuming dairy products. The condition, also called lactose malabsorption, is usually harmless, but its symptoms can be uncomfortable. Most people with lactose intolerance can manage the condition without giving up all dairy products.

Lactase deficiency, an enzyme produced in the small intestine, is usually responsible for lactose intolerance. Many people have low lactase levels but can digest dairy products without problems. If you are actually lactose intolerant, lactase deficiency leads to symptoms after you eat dairy products.

Signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or drinking foods containing lactose. General signs and symptoms include:

  • Diarrhea
  • Nausea and sometimes vomiting
  • Abdominal cramps
  • Inflate
  • Gases

Make an appointment with your doctor if you often experience symptoms of lactose intolerance after eating dairy products, especially if you are worried about getting enough calcium.


Lactose intolerance occurs when the small intestine does not produce enough enzyme (lactase) to digest milk sugar (lactose).

Normally, lactase converts milk sugar into two simple sugars, glucose and galactose, which are absorbed into the bloodstream through the intestinal lining.

If you are lactase deficient, the lactose in food moves to the large intestine instead of being processed and absorbed. In the colon, normal bacteria interact with undigested lactose, causing the signs and symptoms of lactose intolerance.

There are three types of lactose intolerance. Various factors cause lactase deficiency underlying each type.

Primary lactose intolerance

This is the most common type of lactose intolerance. People with primary lactose intolerance begin their lives by producing large amounts of lactase, a must for babies who get all their nutrients from milk. As children replace milk with other foods, their lactase production usually decreases but remains high enough to digest the amount of dairy in a normal adult diet.

In primary lactose intolerance, lactase production drops dramatically, making it difficult for adults to digest dairy products. Primary lactose intolerance is genetically determined, which occurs in a significant proportion of people of African, Asian, or Hispanic ancestry. This condition is also common among Mediterranean or South European ancestry.

Secondary lactose intolerance

This form of lactose intolerance occurs when the small intestine reduces its production of lactase after illness, injury, or surgery involving the small intestine. Diseases associated with secondary lactose intolerance include celiac disease, bacterial overgrowth, and Crohn’s disease. Treating the underlying disorder can restore lactase levels and improve symptoms and signs, although this may take some time.

Congenital or developing lactose intolerance

This disorder is passed from generation to generation in a form of inheritance called autosomal recessive. Premature babies may also be lactose intolerant due to insufficient lactase levels.

Factors that may make you or your child more likely to become lactose intolerant, include:

  • Growing up. Lactose intolerance usually appears in adulthood. This disease is rare in children and young children.
  • Ethnos. Lactose intolerance is most common in African, Asian, Hispanic, and American Indian people.
  • Premature birth. Babies born prematurely may have low lactase levels because the small intestine does not develop lactase-producing cells until late in the third trimester.
  • Diseases affecting the small intestine. Small intestinal problems that can cause lactose intolerance include bacterial overgrowth, celiac disease, and Crohn’s disease.
  • Some treatments for cancer. If you’ve had radiation therapy for abdominal cancer or intestinal complications from chemotherapy, you’re at increased risk of lactose intolerance.

Explained how lactose intolerance affects women




Lactose is a sugar naturally found in milk and dairy products. Lactose intolerance occurs due to lactose malabsorption. This is a condition in which the small intestine cannot digest or break down all the lactose a person eats or drinks.

According to the National Institutes of Health (NIH), most people with lactose intolerance can consume some lactose without any symptoms. This will depend on each case and their level of intolerance.

If a person is lactose intolerant, they will experience severe discomfort. The most common pains associated with the digestive system are bloating, diarrhea, and gas after eating foods or drinks that contain lactose.

Products containing lactose

Lactose is present in milk and all dairy products such as yogurt, cheese and ice cream. It is also present in many finished products. This long list includes: deli meats, crackers, salad dressings, cereals, breads and other baked goods.

Lactose intolerance should not be confused with milk allergy. The latter is caused by a problem with the immune system. Symptoms can range from mild (rash or itching) to severe (shortness of breath or wheezing). This is more common in children than in adults.

Calcium and vitamin D deficiency

Lactose intolerance can prevent you from getting enough calcium and vitamin D, which are important for bone health. It promotes bone health and reduces the risk of fractures. It also affects blood clotting, the functioning of the nervous system and the prevention of cardiovascular disease, explains the Spanish Society of Dietetics and Nutritional Sciences (SEDCA).

As for vitamin D, it is important for the proper absorption of calcium and phosphorus, so a deficiency can also reduce the levels of these minerals, which are essential for bone health, among other things. An association has also been found between adequate vitamin D levels and a lower risk of cardiovascular disease.

How does lactose intolerance affect women?

Women especially need to get enough calcium and vitamin D throughout their lives so that they can build and maintain bone density and reduce the risk of osteoporosis later in life.

According to the Office of Women’s Health (OASH), osteoporosis is a condition in which bones become weak and break more easily. And women have a higher risk of osteoporosis than men.

In particular, according to OASH, women are more likely to suffer from osteoporosis for the following reasons:

– Women tend to have smaller, thinner, and less dense bones than men.

– women tend to live longer and bone loss occurs naturally with age.

– In addition, women lose more bone mass after menopause due to very low levels of the hormone estrogen.