Pasteurisation does not cause lactose intolerance

4 September 2023
What was claimed

Pasteurisation of milk is one of the main causes of lactose intolerance.

Our verdict

Lactose intolerance is caused by a deficiency in the enzyme that breaks it down, and by other gut diseases. Raw milk has not been shown to improve symptoms of the condition.

A video on Instagram and Facebook about raw milk claims “pasteurisation is one of the main reasons why so many people are lactose intolerant”. This is not true. Pasteurisation does not cause lactose intolerance.

The video was posted by Liz Seibert, a model with over 300,000 followers between the two platforms. She has also posted it on TikTok, where she has over a million followers.

Bad information about health can cause direct harm by encouraging people to consume foods or medicines that might make them unwell, or by making them avoid treatment that they need. 

We have written before about false claims by people with large social media followings claiming to offer legitimate health advice, including similar claims about raw milk.

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As the video explains, pasteurisation is a process of heating milk to kill harmful bacteria. Raw milk is a term for milk that hasn’t been through this process. 

The Food Standards Agency advises that “raw or unpasteurised milk and cream may contain harmful bacteria that can cause food poisoning. People with a weaker immune system are particularly vulnerable to food poisoning and should not consume it.” 

This includes people aged 65 or over, those who are pregnant, those who have a compromised immune system such as cancer patients, and infants and small children.

Lactose intolerance

Lactose is a sugar found in milk made by mammals. Human breast milk contains it, as does cow’s milk. It is broken down in our gut by lactase, a specific enzyme for this sugar.

The most common cause of lactose intolerance is a genetic mutation that leads to a lack of lactase as we grow and become less dependent on milk. It can also be caused by other gut diseases.

People with the condition will struggle to digest the lactose in dairy products, causing tummy upsets and other symptoms. The issue can start at any age, with some people producing less lactase as they get older.

Pasteurised milk does not cause the condition.

Enzymes and probiotics

Ms Seibert claims that “the enzymes and probiotics in the dairy that actually makes it digestible for humans” are killed during the pasteurisation process.

Lactase, the important enzyme for milk digestion in humans, is not present in milk, raw or not.

On the issue of probiotics, 2012 review from scientists linked to the Belgian Federal Agency for the Safety of the Food Chain did find that raw milk can contain some probiotic bacteria, but in amounts that would need to be “1000 to 10 000 times higher than the amount actually present in raw milk” to have any effect.

As we have written before, studies looking at raw milk consumption and lactose intolerance haven’t found any association between the two, nor improved symptoms when switching to or from pasteurised milk.

We contacted Ms Seibert’s agency Dulcedo Management who declined to comment.

Featured image courtesy of Ouça e Relaxe

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