Lactose intolerance is the inability of the body to fully digest lactose, so after consumption of dairy products, patients may experience diarrhea, exhaustion and flatulence. This condition is also known as Lactose Malabsorption, and although it does not affect the body, these symptoms are uncomfortable. However, most lactose intolerant patients can tolerate these discomfort, so there is no need to quit all dairy products completely.

How common is lactose intolerance?

Lactose intolerance is very common and can occur regardless of age. Patients can try to reduce the risk factors and discuss with your doctor if you need more information.

Symptoms of lactose intolerance

Symptoms of lactose intolerance usually occur within 30 minutes to 2 hours after consuming food containing lactose.
Common symptoms include:

Abdominal spasms

The above does not contain all symptoms, please ask your doctor if you have any concerns.

When should I see a doctor?

If symptoms of lactose intolerance occur frequently after ingestion of dairy products, you should contact your doctor, especially those with osteoporosis.

Causes of lactose intolerance

The lack of lactase in the body, which is an enzyme in the human intestine, is the main cause of lactose intolerance. Generally, lactase converts lactose into two types of monosaccharides: glucose and galactose, which are absorbed into the blood through the intestinal wall. With lactose intolerance, lactose from food enters the colon and is not digested or absorbed. In the colon, normal bacteria interact with undigested lactose, symptoms of lactose intolerance occur. Many do not have much lactase in the intestine, but there are still ways to digest dairy products.

Lactose intolerance is divided into 3 different types:

Primary lactose intolerance

This is the most common type that causes the amount of lactase to decrease with age, making it impossible for patients to absorb dairy products well in adulthood. Patients produce lactase in infancy, as babies must rely on milk as the primary source of nutrition. But in childhood, when staples are changed from milk to other foods, their lactase is reduced, but still enough to digest the dairy content in a regular adult diet.
Primary lactose intolerance is genetically determined and often occurs in Africa, Asia, Hispanics, Mediterranean or Southern Europeans, and Amerindians.

Continued lactose intolerance

Continuing lactose intolerance occurs due to diseases such as celiac disease, excessive growth of small intestine bacteria, Crohn’s disease, injury or surgery, resulting in a decrease in the production of lactase from the small intestine. Treatment of these underlying diseases or trauma takes time, but ultimately helps to raise lactase levels in the body and improve the symptoms of lactose intolerance.

Congenital or Developmental lactose intolerance

When a baby is born, even with lactose intolerance, it is rarely due to a total lack of lactase activity; these symptoms are caused by chromosomal recessive heredity, which both parents must have the same genetic variation in order for the baby to show this symptom. In addition, premature babies may also have lactose intolerance due to lactase deficiency.

Risk factors for lactose intolerance

There are many risk factors for lactose intolerance, such as:

Increases in age: lactose intolerance is common in adults and is less common in infants or children.


Lactose intolerance is most common in Africa, Asia, Hispanics, Mediterranean and Southern Europeans, and Amerindians.

Premature babies

As a result of premature birth, these babies have not developed lactase producing cells before birth, resulting in lower lactase levels.

Small intestine related diseases

Small intestine diseases may lead to lactose intolerance, including small intestinal bacteria overgrowth, coeliac disease, clones disease, etc.
Specific cancer treatment: The risk of lactose intolerance increases if you have received radiation therapy for gastric cancer or have had a intestinal complication after chemotherapy.

Diagnosis and treatment of lactose intolerance

The following information does not represent professional medical advice, please ask your doctor for more information.

How to diagnose lactose intolerance?

The doctor will judge the patient’s symptoms and response to dairy products, and can make a diagnosis based on the following tests:

Lactose tolerance test

This test evaluates the body’s reaction to high-concentration lactase liquids, and after 2 hours of drinking the liquid, a blood test is performed to measure the glucose content in the blood. If the blood glucose level is not elevated, the body cannot digest and absorb lactose properly.

Hydrogen Exhaust Test

In this test, subjects are required to drink a liquid containing a high concentration of lactose and measure the amount of hydrogen exhaled at intervals. Generally speaking, only a very small amount of hydrogen can be detected, but if the body cannot digest lactose, the undigested lactose ferments in the colon, releases hydrogen and other gases, absorbed by the intestine and eventually discharged. If a higher than average amount of hydrogen exhaled is detected, it means that lactose is not fully digested and absorbed.

Stool Acid Test

If infants and children are not suitable for other tests, the stool acid test can be used. Undigested lactose fermentation produces lactic acid and other acidic ingredients that can be detected in stool samples.

How to treat lactose intolerance?

There is no way to improve lactase production in the body. However, patients can avoid the discomfort of lactose intolerant by:
Avoiding excessive intake of milk or dairy products
Consuming only small amounts of dairy products
Choosing low lactose ice cream and milk
Adding lactose decomposition enzyme to normal milk

Lifestyle Adjustment and Home Therapy for Lactose Intolerance

The following lifestyle and home remedies may help with lactose intolerance:

Attention to nutrition

Reducing dairy intake does not mean that calcium intake is insufficient. Patients can get calcium from the following foods: broccoli, calcified foods such as bread and juice, milk substitutes (such as soy milk and rice milk), orange, spotted beans, rhubarb, spinach.

At the same time, you should get enough vitamin D, which is common in calcium-added products. Eat eggs, liver and yogurt. You can also get vitamin D from the sun,. Many adults don’t have enough vitamin D even if they don’t have enough dairy intake, so you can discuss with your physician how to take vitamin D and calcium supplements.

Reduce dairy intake

Many lactose intolerant patients can still enjoy dairy products and do not experience very difficult symptoms. Patients can try to adapt their body slowly to dairy products and may increase their tolerance to lactose. Some people are more receptionable to whole dairy products such as whole milk and cheese than low-fat or skim dairy products. Here are some ways to change your diet to reduce lactose intolerance:

Take small portions of dairy products, e.g. do not drink more than 118 ml of milk once. Smaller parts of dairy products are less likely to cause gastrointestinal problems.
Drink milk with other foods that can slow down the digestion process and relieve lactose intolerance.
Try a variety of dairy products because each dairy product has a different lactose content. For example, hard cheese, such as swiss or cheddar, has less lactose content and generally does not cause symptoms. Fermented dairy products such as yogurt are also less problematic, as lactose is decomposed naturally by enzymes during fermentation.

Choose low lactose or zero lactose products.

Use lactose decomposition enzymes, or commercially available tablets and drops containing lactose decomposition enzymes (Dairy Ease or Lactaid, etc.) to help digest dairy products. Patients may try to take before meals or drops into milk, but these products may not be effective for everyone.
If you have any concerns, ask your doctor to choose the best treatment.

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