Lactose Intolerance

Lactose Intolerance Video

Hi, and welcome to this review of lactose intolerance! In this video, we will be discussing what lactose intolerance is, how it develops, how it’s diagnosed, and how it’s treated. Let’s get started!

Causes and Types

First, what is lactose intolerance? You can probably infer from the name that lactose intolerance is the body’s inability to break down lactose, the sugar found in milk and other dairy products. There is an enzyme in the small intestine called lactase that breaks down this sugar, and when it is in very low quantities or absent, the small intestine will not be able to digest foods that contain lactose.

There are three main types of lactose intolerance. Primary lactose intolerance is an acquired lactase deficiency that occurs after the infant is weaned and occurs in 75% of the world’s population, especially adults with Asian, African, and Hispanic ancestry.

Secondary lactose intolerance is a result of damage to the mucosa of the small intestine. Illnesses that may cause secondary lactose intolerance include intestinal infection, celiac disease, bacterial overgrowth, and Crohn’s disease. It may be reversed if the underlying cause is treated.

Congenital or developmental lactose intolerance occurs in infants who are born lacking the lactase enzyme. This rare type of intolerance is passed on as an autosomal recessive trait, meaning both parents need to carry this gene for it to pass on to the child.

Recognizing Symptoms

The symptoms of lactose intolerance typically occur between 30 minutes and two hours after consuming a product containing lactose. Symptoms may include:

  • abdominal cramps
  • bloating
  • gas
  • diarrhea
  • nausea

The severity of the symptoms depends on how much lactose was consumed and how much lactase the person has in their system.

Diagnosing Lactose Intolerance

To diagnose a patient with lactose intolerance, you will need to take a detailed history of the patient’s medical condition, including diet. You will also need to ask for a detailed history of the patient’s symptoms. After performing a physical examination, there are some tests that will rule out or confirm lactose intolerance.

The most common test is the H2 breath test, which measures the amount of hydrogen in the patient’s breath after consuming a lactose-rich drink. If the small intestine is unable to digest the lactose, the bacteria in the large intestine will break it down instead. This process is called fermentation, and it causes hydrogen and other gases to be released. These gases are absorbed and eventually exhaled. If the patient isn’t fully digesting lactose, the hydrogen breath test will show a higher than normal amount of hydrogen in their breath.

The lactose tolerance test is another option but is rarely used. Two hours after consuming a lactose-rich drink, the patient undergoes blood tests to measure the amount of glucose in the bloodstream. If the glucose level doesn’t rise, it means the patient isn’t properly digesting and absorbing the lactose.

In the case of an infant or child, a stool acidity test may be performed. This test measures the amount of lactic acid in a stool sample. High levels of lactic acid are a result of fermentation in the large intestines if the lactose was not digested properly.

Treatment Strategies

Treatment options for lactose intolerance vary, but the most common thing patients are advised to do is avoid foods that contain high amounts of lactose. Typically, yogurt and aged cheeses are tolerated better since they contain less lactose.

Fortunately, people with lactose intolerance can still receive enough of the nutrients normally found in lactose-rich foods in various other foods. Calcium, for example, is often associated with milk but is also found in many other types of foods such as broccoli, salmon, oranges, and almonds. There are also many lactose-free food substitutes that can take the place of foods containing lactose.

Patients can also use lactase enzyme tablets or drops. Tablets are often taken just before a meal or snack, and the drops are usually added to a glass of milk. Each person will respond differently to treatment methods, so it’s important to find the best option for each patient individually.

Okay, before we go, let’s look over a couple of quick review questions:

Review Questions

1. Which of the following describes the most common type of lactose intolerance?

A. A result of damage to the mucosa of the small intestine
B. An acquired lactase deficiency that occurs after the infant is weaned
C. Passed on as an autosomal recessive trait
D. A result of celiac disease

The correct answer is B.

This describes Primary lactose intolerance, which is the most common, affecting 75% of the world’s population.


2. Which of the following is NOT a recommended treatment option for lactose intolerance?

  1. Remove all foods that contain lactose from the diet
  2. Consuming lactose-free substitutes, such as lactose-free milk
  3. Utilizing lactase enzyme drops or tablets before meals
  4. Increase intake of lactose-free foods that contain similar nutrients to lactose-rich foods
The correct answer is A.

It is not generally recommended to completely remove all foods that contain lactose from the diet. There are some foods that contain low amounts of lactose that most people are not as affected by, such as some cheeses and yogurt. Eating foods with low amounts of lactose will help to ensure you are receiving all of the necessary nutrients your body needs on a daily basis.

That’s all for this review! Thanks for watching, and happy studying!


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by Mometrix Test Preparation | Last Updated: February 8, 2024