{"id":10809,"date":"2020-04-22T13:00:39","date_gmt":"2020-04-22T17:00:39","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=10809"},"modified":"2026-04-06T14:02:30","modified_gmt":"2026-04-06T18:02:30","slug":"what-is-lactose-intolerance","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/what-is-lactose-intolerance\/","title":{"rendered":"What is lactose intolerance? Causes, symptoms, and treatments"},"content":{"rendered":"

What is lactose intolerance?<\/a> | Causes<\/a> | Symptoms<\/a> | Treatments<\/a> | When to call a doctor<\/a><\/p>\n

If you\u2019ve ever had an upset stomach after drinking milk or eating ice cream, you may be lactose intolerant. Lactose is a sugar found in milk and other dairy products. Research suggests that around <\/span>two-thirds<\/span><\/a> of the global population is affected by some form of lactose intolerance. Here\u2019s what that means for you.<\/span><\/p>\n

What is lactose?<\/b><\/h2>\n

Lactose is a sugar molecule found in dairy products. Specifically, it is a disaccharide (double sugar) that the body breaks down into the simple sugars glucose and galactose. The body uses these sugars for energy and different functions, such as repairing cells, building muscles, and fueling everyday activities. Lactose makes up 2% to 8% of milk\u2014and is even found as an inactive ingredient in some medications.\u00a0<\/span><\/p>\n

What is lactose intolerance?<\/strong><\/h2>\n

Lactose intolerance (also called lactose malabsorption) is the inability to digest lactose. Normally, an enzyme called lactase in the small intestine helps break down lactose so it can be absorbed. People with lactose intolerance don\u2019t have enough lactase, which leads to lactose remaining unabsorbed. The unabsorbed lactose moves on to the large intestine where it is fermented by bacteria, often causing an upset stomach and other digestive symptoms.\u00a0<\/span><\/p>\n

Some groups of people may be more prone to developing lactose intolerance than others. <\/span>Risk factors<\/span><\/a> for developing lactose intolerance include being of African American, American Indian, Asian, or Hispanic descent; being older; or being born prematurely.\u00a0\u00a0<\/span><\/p>\n

Causes of lactose intolerance<\/strong><\/h2>\n

Lactose intolerance is a chronic condition that can develop at any age due to a number of causes. These causes are divided into four different categories.<\/span><\/p>\n

Primary<\/span><\/h3>\n

Primary lactose intolerance, also known as lactase nonpersistence, is the most common form of lactose intolerance. It is characterized by a decrease in lactase activity as a person gets older. Primary lactose intolerance usually develops in adolescence and early adulthood.\u00a0\u00a0\u00a0<\/span><\/p>\n

Secondary<\/span><\/h3>\n

Secondary lactose intolerance is caused by medical conditions or diseases that damage the intestinal lining. Certain infections and inflammatory diseases can injure the intestinal lining where lactase is normally made, leading to decreased production of lactase. These infections and diseases include celiac disease, ulcerative colitis, and Crohn\u2019s disease.\u00a0<\/span><\/p>\n

Congenital<\/span><\/h3>\n

Congenital lactose intolerance is caused by an inheritance of an autosomal recessive disorder. This type of lactose intolerance is rare and develops at birth. Studies suggest that mutations in the <\/span>LCT gene<\/span><\/a> are responsible for this type of lactose intolerance.\u00a0<\/span><\/p>\n

Developmental<\/span><\/h3>\n

Developmental lactose intolerance occurs due to an underdeveloped small intestine in premature infants. This type of lactose intolerance occurs in babies that are born at 28 to 37 weeks. However, the baby\u2019s small intestine grows and develops over time to resolve the issue.\u00a0<\/span><\/p>\n

The two main types of lactose intolerance are primary and secondary lactose deficiency. Primary lactose intolerance is much more common than secondary lactose intolerance. In North America, 79% of Native Americans, 75% of African Americans, 51% of Hispanics, and 21% of Caucasians have <\/span>primary lactose intolerance<\/span><\/a>.\u00a0\u00a0\u00a0<\/span><\/p>\n

Symptoms of lactose intolerance<\/strong><\/h2>\n

Signs of lactose intolerance are easily recognizable. If you\u2019ve just eaten dairy products and have any of the following symptoms within 30 minutes to two hours after eating, you may be lactose intolerant.\u00a0\u00a0\u00a0\u00a0<\/span><\/p>\n

    \n
  1. Bloating<\/span><\/li>\n
  2. Flatulence<\/span><\/li>\n
  3. Diarrhea<\/span><\/a>\u00a0<\/span><\/li>\n
  4. Nausea<\/span><\/li>\n
  5. Vomiting\u00a0\u00a0<\/span><\/li>\n
  6. Abdominal cramping<\/span><\/li>\n
  7. Indigestion<\/span><\/li>\n
  8. Belching\u00a0<\/span><\/li>\n<\/ol>\n

    These symptoms all happen because the small intestine can\u2019t properly digest the sugar in dairy products. As a result, bacteria in the large intestine ferment the undigested lactose, causing a buildup of gas and water. Adults and <\/span>children<\/span><\/a> will experience many of the same symptoms if they\u2019re lactose intolerant.\u00a0<\/span><\/p>\n

    Lactose intolerance is a manageable condition that does not usually cause serious symptoms. Some people with lactose intolerance don\u2019t experience any symptoms at all. The severity of symptoms depends on the person, their response to the foods they eat, and other factors.\u00a0\u00a0<\/span><\/p>\n

    Lactose intolerance may be confused for a milk allergy, but being allergic to milk is a very different thing. A milk allergy is caused by an immune reaction to milk proteins and can be life-threatening. Infants and children with a milk allergy may have symptoms such as hives, wheezing, vomiting, and swelling of the face or throat. Anaphylaxis is a severe, life-threatening reaction to milk products that warrants immediate medical attention.\u00a0<\/span><\/p>\n

    How is lactose intolerance diagnosed?<\/b><\/h2>\n

    How do you know if you have lactose intolerance? Some people may suspect they have lactose intolerance if they experience digestive symptoms after consuming a dairy product. However, many of the symptoms of lactose intolerance are similar to those of irritable bowel syndrome, celiac disease, and gastrointestinal infections. If you suspect you are lactose intolerant, it is important to speak with your primary care provider to get a formal diagnosis and make sure there are no other medical or nutritional concerns.\u00a0<\/span><\/p>\n

    A healthcare provider will diagnose lactose intolerance by evaluating your overall medical history. They may ask you about your personal or family medical history and perform a physical exam to pinpoint the cause of your symptoms. They may also perform medical tests to help accurately diagnose the condition. Diagnostic medical tests for lactose intolerance include:<\/span><\/p>\n

    Hydrogen breath test<\/span><\/h3>\n

    A <\/span>hydrogen breath test<\/span><\/a>, which is administered by a gastroenterology specialist, measures how much hydrogen is in the breath after consuming dairy products. It tests for hydrogen because the body turns undigested lactose into hydrogen gas.\u00a0\u00a0<\/span><\/p>\n

    Blood glucose test<\/span><\/h3>\n

    Blood glucose tests are another type of laboratory test that can help diagnose lactose intolerance. A blood glucose test looks for elevated blood glucose levels after a person consumes a standard amount of lactose. If blood glucose levels don\u2019t go up, the body isn\u2019t breaking lactose down into glucose.\u00a0<\/span><\/p>\n

    Stool acidity test<\/span><\/h3>\n

    The bacteria in the large intestine ferment lactose, releasing lactic acid and causing high acidity in the stool. A healthcare provider may test the stool for a low pH level, which would indicate high acidity. Because a stool acidity test is not specific for lactose malabsorption, a healthcare provider may also recommend removing dairy products from the diet.\u00a0<\/span><\/p>\n

    Removal of dairy items from the diet<\/span><\/h3>\n

    A healthcare provider may recommend<\/span> removing dairy and milk items from the diet and then slowly reintroducing those items back into the diet. If symptoms are absent while abstaining from dairy products and reappear after consuming dairy products, lactose intolerance may be a concern.<\/span><\/p>\n

    Lactose intolerance treatments<\/strong><\/h2>\n

    Managing this intolerance is usually a matter of making diet changes, but lactase enzyme supplements may be helpful for some people.<\/span><\/p>\n

    Diet changes<\/b><\/h3>\n

    Many doctors agree that the best way to treat an intolerance is to avoid consuming lactose to begin with. Lactose is in dairy products <\/span>and<\/span><\/i> non-dairy products, so reading food and medication labels is important.<\/span><\/p>\n

    Dairy foods and drinks that are high in lactose include:<\/span><\/p>\n