Have a symptom?
See what questions
a doctor would ask.

Lactose Intolerance

Lactose Intolerance: Introduction

Lactose intolerance is an inability of the body to digest lactose, a sugar found in milk and other dairy products. Lactose intolerance is often incorrectly referred to as a "milk allergy" or "lactose allergy". Lactose intolerance however, is not an allergy, because it does not involve a reaction of the immune system. Lactose is most correctly described as an adverse reaction, but not an allergy, to food products that contain lactose.

Lactose intolerance is the result of the body's inability to produce enough or any lactase, an enzyme found in the small intestine that digests lactose. This results in such symptoms nausea, bloating, cramping and diarrhea after eating a food or beverage that contains lactose. Common foods and beverages that contain lactose and can cause lactose intolerance include milk, ice cream, soft cheeses, yogurt, sour cream and any food that is made with dairy products.

Symptoms of lactose intolerance vary between individuals depending on such factors as how much lactase an individual makes and the amount of lactose consumed. In rare cases, lactose intolerance can result in serious complications in an infant, such as persistent diarrhea and failure to gain weight. For more details about symptoms and complications, see symptoms of lactose intolerance.

Lactose intolerance can occur in any age group or population. However, people of African, Jewish, Hispanic, Asian, Middle Eastern and Native American descent are at risk for developing lactose intolerance.

Diagnosing lactose intolerance begins with taking a thorough personal and family medical history, including symptoms, and completing a physical examination. Diagnostic testing may include a lactose tolerance test, hydrogen breath test and/or stool acidity test.

A chemistry panel is a blood test that can evaluate if lactose intolerance and diarrhea has lead to the complication of dehydration. An urinanalysis can also help to determine dehydration.

A diagnosis of lactose intolerance and its cause can easily be delayed or missed because lactose intolerance may be intermittent and for other reasons. For information on misdiagnosis, refer to misdiagnosis of lactose intolerance.

There is no cure for lactose intolerance. However, with treatment symptoms can be minimized or eliminated. Treatment includes dietary changes, calcium supplements, and taking a lactose enzyme. For more information on treatment, refer to treatment of lactose intolerance. ...more »

Lactose Intolerance: Lactose intolerance is a difficulty properly digesting lactose (milk sugar) and the various dairy products that contain lactose. It is very common with an estimated 30-50 million Americans affected, especially African Americans, Native Americans, and Mexican Americans. Lactose intolerance causes various digestive symptoms, usually after meals, including cramps, bloating, gas, and diarrhea. ...more »

Lactose Intolerance: Symptoms

Symptoms of lactose intolerance can be mild to severe and vary between individuals. Each person with lactose intolerance can have different tolerances for lactose. Symptom severity can differ based on such elements as how much of the enzyme lactase a body produces and the amount of food or beverages that contain lactose that have been consumed.

Symptoms of ...more symptoms »

Lactose Intolerance: Treatments

Lactose intolerance cannot be cured and there is no way to increase the amount of the enzyme lactase that the body produces. Lactase is necessary for the digestion of foods that contain lactose. However, people with lactose intolerance may be able to digest varying amounts of foods and beverages that contain lactose by taking supplements that contain the enzyme lactase. These supplements are ...more treatments »

Lactose Intolerance: Misdiagnosis

Diagnosing lactose intolerance and its cause may be delayed or missed because in some cases, lactose intolerance may not be severe enough for a person to seek medical care. In addition, symptoms of lactose can resemble other conditions and diseases, such as irritable bowel syndrome, Crohn's disease, food poisoning, gastroenteritis or celiac ...more misdiagnosis »

Symptoms of Lactose Intolerance

Treatments for Lactose Intolerance

  • Low-lactose diet
  • Lactose-reduced milk
  • Milk-free diet
  • Dairy-free diet - avoiding all dairy products, not just milk
  • Lactase enzyme pills
  • more treatments...»

Home Diagnostic Testing

Home medical testing related to Lactose Intolerance:

Wrongly Diagnosed with Lactose Intolerance?

Lactose Intolerance: Related Patient Stories

Lactose Intolerance: Deaths

Read more about Deaths and Lactose Intolerance.

Alternative Treatments for Lactose Intolerance

Alternative treatments or home remedies that have been listed in various sources as possibly beneficial for Lactose Intolerance may include:

  • Lactase supplement
  • Low-lactose diet
  • Eliminate dietary lactose (including whey, milk byproducts, nonfat dry milk powder, malted milk, buttermilk, dry milk solids)
  • Calcium
  • Vitamin D
  • more treatments »

Diagnostic Tests for Lactose Intolerance

Test for Lactose Intolerance in your own home

Click for Tests

Lactose Intolerance: Complications

Read more about complications of Lactose Intolerance.

Causes of Lactose Intolerance

More information about causes of Lactose Intolerance:

Disease Topics Related To Lactose Intolerance

Research the causes of these diseases that are similar to, or related to, Lactose Intolerance:

Lactose Intolerance: Undiagnosed Conditions

Commonly undiagnosed diseases in related medical categories:

Misdiagnosis and Lactose Intolerance

Mild worm infections undiagnosed in children: Human worm infestations, esp. threadworm, can be overlooked in some cases, because it may cause only mild or even absent symptoms. Although the most common more »

Chronic digestive conditions often misdiagnosed: When diagnosing chronic symptoms of the digestive tract, there are a variety of conditions that may be misdiagnosed. The more »

Intestinal bacteria disorder may be hidden cause: One of the lesser known causes of diarrhea is an imbalance of bacterial in the gut, sometimes called intestinal imbalance. more »

Antibiotics often causes diarrhea: The use of antibiotics are very likely to cause some level of diarrhea in patients. The reason is that antibiotics kill off not only "bad" bacteria, but can also kill the "good" bacteria in the more »

Food poisoning may actually be an infectious disease: Many people who come down with "stomach symptoms" like diarrhea assume that it's "something I ate" (i.e. more »

Mesenteric adenitis misdiagnosed as appendicitis in children: Because appendicitis is one of the more feared conditions for a child more »

Blood pressure cuffs misdiagnose hypertension in children: One known misdiagnosis issue with hyperension, arises in relation to the simple equipment used to test blood pressure. The more »

Celiac disease often fails to be diagnosed cause of chronic digestive symptoms: One of the most common chronic digestive conditions is celiac disease, a malabsorption disorder with a variety more »

Children with migraine often misdiagnosed: A migraine often fails to be correctly diagnosed in pediatric patients. These patients are not the typical migraine sufferers, but migraines can also occur in children. See misdiagnosis more »

Vitamin B12 deficiency under-diagnosed: The condition of Vitamin B12 deficiency is a possible misdiagnosis of various conditions, such as multiple sclerosis (see symptoms of multiple sclerosis). See symptoms of Vitamin more »

Chronic digestive diseases hard to diagnose: There is an inherent difficulty in diagnosing the various types of chronic digestive diseases. Some more »

Lactose Intolerance: Research Doctors & Specialists

Research related physicians and medical specialists:

Other doctor, physician and specialist research services:

Hospitals & Clinics: Lactose Intolerance

Research quality ratings and patient safety measures for medical facilities in specialties related to Lactose Intolerance:

Choosing the Best Hospital: More general information, not necessarily in relation to Lactose Intolerance, on hospital performance and surgical care quality:

Lactose Intolerance: Rare Types

Rare types of diseases and disorders in related medical categories:

Latest Treatments for Lactose Intolerance

Evidence Based Medicine Research for Lactose Intolerance

Medical research articles related to Lactose Intolerance include:

Click here to find more evidence-based articles on the TRIP Database

Lactose Intolerance: Animations

Prognosis for Lactose Intolerance

Prognosis for Lactose Intolerance: Excellent. Well controlled through dietary changes.

Research about Lactose Intolerance

Visit our research pages for current research about Lactose Intolerance treatments.

Clinical Trials for Lactose Intolerance

The US based website lists information on both federally and privately supported clinical trials using human volunteers.

Some of the clinical trials listed on for Lactose Intolerance include:

Statistics for Lactose Intolerance

Lactose Intolerance: Broader Related Topics

Lactose Intolerance Message Boards

Related forums and medical stories:

User Interactive Forums

Read about other experiences, ask a question about Lactose Intolerance, or answer someone else's question, on our message boards:

Article Excerpts about Lactose Intolerance

Lactose Intolerance: NIDDK (Excerpt)

Lactose intolerance is the inability to digest significant amounts of lactose, the predominant sugar of milk. This inability results from a shortage of the enzyme lactase, which is normally produced by the cells that line the small intestine. (Source: excerpt from Lactose Intolerance: NIDDK)

Why Does Milk Bother Me: NIDDK (Excerpt)

Lactose intolerance means that you cannot digest foods with lactose in them. Lactose is the sugar found in milk and foods made with milk. (Source: excerpt from Why Does Milk Bother Me: NIDDK)

Food Allergy and Intolerances, NIAID Fact Sheet: NIAID (Excerpt)

Another cause of food intolerance that is often confused with a food allergy is lactase deficiency. This most common food intolerance affects at least one out of ten people. Lactase is an enzyme that is in the lining of the gut. This enzyme degrades lactose, which is in milk. If a person does not have enough lactase, the body cannot digest the lactose in most milk products. Instead, the lactose is used by bacteria, gas is formed, and the person experiences bloating, abdominal pain, and sometimes diarrhea. There are a couple of diagnostic tests in which the patient ingests a specific amount of lactose and then the doctor measures the body's response by analyzing a blood sample. (Source: excerpt from Food Allergy and Intolerances, NIAID Fact Sheet: NIAID)

Lactose Intolerance: NWHIC (Excerpt)

Lactose intolerance is a condition in which the body is not able to easily digest foods that contain lactose, or the natural sugar that is found in dairy products. Once lactose is in the body, it needs to be broken down into two simple sugars, glucose and galactose, to be absorbed into the blood stream. People who are lactose intolerant have a shortage of lactase enzymes that break down lactose into these sugars. (Source: excerpt from Lactose Intolerance: NWHIC)

Definitions of Lactose Intolerance:

The condition resulting from the absence or deficiency of LACTASE in the MUCOSA cells of the GASTROINTESTINAL TRACT, and the inability to break down LACTOSE in milk for ABSORPTION. Bacterial fermentation of the unabsorbed lactose leads to symptoms that range from a mild indigestion (DYSPEPSIA) to severe DIARRHEA. Lactose intolerance may be an inborn error or acquired. - (Source - Diseases Database)

Congenital disorder consisting of an inability to digest milk and milk products; absence or deficiency of lactase results in an inability to hydrolyze lactose - (Source - WordNet 2.1)


By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.

Home | Symptoms | Diseases | Diagnosis | Videos | Tools | Forum | About Us | Terms of Use | Privacy Policy | Site Map | Advertise