Health Tips

Are you someone who would get stomach upset after consuming dairy products, or know someone who would? Lactose intolerance may be the culprit here.

Lactose intolerance is a condition that makes it hard for a person’s body to digest dairy products, i.e. milk and food made with milk, such as cheese. People with lactose intolerance may experience the following after ingesting dairy products:

• Stomach cramps (usually around or below the belly button)

• Bloating

• Flatulence, i.e. feel ‘gassy’

• Farting

• Nausea

• Diarrhoea (often it is bulky, foamy, and watery)

The severity of your symptoms and when they appear depends on the amount of lactose you have consumed. Some people may still be able to drink a small glass of milk without triggering any symptoms, while others may not even be able to have milk in their tea or coffee.

Lactose intolerance is more commonly seen in African Americans, Hispanics, Asians, Asian Americans, and Native Americans. The prevalence of lactose intolerance is low in children younger than six years and increases with age.

What causes lactose intolerance?

In people who do not have lactose intolerance, the body makes an enzyme called lactase that breaks down lactose, the main form of sugar found in milk. In people who do have lactose intolerance, the body either does not make enough of the enzyme (lactase deficiency), or the enzyme does not work as well as it should. As a result, the lactose is not broken down properly and stays in the digestive system, where it's fermented by bacteria. This leads to the production of various gases, which cause the symptoms associated with lactose intolerance.

Lactose intolerance is linked to genetics, prematurity in babies, or underlying intestinal diseases. Depending on the underlying reason why the body's not producing enough lactase, lactose intolerance may be temporary or permanent. Most cases that develop in adults are inherited and tend to be lifelong, but cases in young children are often caused by an infection in the digestive system and may only last for a few weeks. 

Lactose intolerance is NOT a food allergy

Indeed, there’s such a thing as dairy allergy, but the symptoms of a dairy allergy are often different from those of lactose intolerance. In the case of an allergy, the body reacts to the protein in milk, rather than to the sugar. Food allergies like dairy allergy involve the body's immune system, whereas lactose intolerance does not. As a result, food allergies like dairy allergy can trigger symptoms such as rash, wheezing and itching; and even a tiny bit of dairy can trigger a reaction. 

How can I test for lactose intolerance?

If you suspect yourself having lactose intolerance, see a doctor for a test. There are two ways to test for lactose intolerance:

• Lactose hydrogen breath test – For this test, you drink a liquid that has lactose in it. Then you breathe into a special machine every 30 minutes. The machine measures how much hydrogen you breathe out. People who have lactose intolerance breathe out more hydrogen than normal.

• Lactose tolerance test – For this test, you drink a liquid that has lactose in it. The doctor or nurse will take blood samples from you when the test starts, and again 1 and 2 hours later. If your blood has low levels of sugar after you drink the lactose, it means you probably have lactose intolerance.

Your doctor or nurse will tell you how to prepare for your test. You will not be able to eat or drink anything for several hours before the test. Plus, you might have to change your medicines or stop smoking for a while before the test.

Health effects of lactose intolerance

The lack of lactase not only triggers uncomfortable and embarrassing symptoms when you eat dairy, it can also lead to certain nutritional deficiencies. This is because milk and other dairy products contain calcium, protein and vitamins, such as A, B12 and D. The lactose in dairy foods also helps your body absorb a number of other minerals, such as magnesium and zinc. Collectively, these nutrients are important for bone health as well as your general well-being. If you're lactose intolerant, getting the right amount of important vitamins and minerals can be tricky, and you’re at risk for osteoporosis and malnutrition. 

Illustration depicting normal standing posture and osteoporosis. Image source: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436

Treating lactose intolerance

Avoiding dairy foods & finding alternatives rich in Vitamin D and calcium

This is perhaps the most straightforward approach to treat lactose intolerance, although it’s a bummer that one may not be able to enjoy the goodness of dairy products as freely. You can work with a nutritionist to devise a diet plan that is suitable for you, learn which food contains dairy and still make sure you have adequate intake of calcium and vitamin D in your diet. Also, when buying food, check the ingredients and watch out for these labels:

• Milk, "milk byproducts," "dry milk powder," and "dry milk solids"

• Lactose

• Whey (whey is milk that has gone sour)

Enzyme supplements

You can consult a community pharmacist on which enzyme supplements you can take to help break down dairy. Of course, they’re no magic bullet – none of them can break down every last bit of lactose, so some people still have symptoms even with an enzyme supplement. But taking enzyme supplements may help you cope with the after effects of dairy products with more ease.

Vitamin D and calcium dietary supplements

If you avoid dairy products completely, you may need to take vitamin D and calcium dietary supplements. Talk to a healthcare professional to check whether you really need such supplementation.

A word from Doc2Us

If you have any questions related to lactose intolerance, you can consult our professional doctors and healthcare professionals on Doc2Us. Doc2Us is a mobile application that allows you to talk to a doctor or any healthcare professionals via text chat at any time and from anywhere. For better communication, you can even send our online doctor images or voice messages related to your medical inquiry.

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Disclaimer: As a service to our users and general public, Doc2Us provides health education contents. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

References

1. UpToDate - Patient education: Lactose intolerance (The Basics)

2. UpToDate - Lactose intolerance: Clinical manifestations, diagnosis, and management

3. NHS - Lactose intolerance

Cover image credit: Sorapop from Freepik

Written by

Ms Joyce Toh