Does milk make mucus worse?

A: No, while it might feel like it, milk does not increase mucus production.

[Image source: iStockphoto]

Have your say

A glass of milk is probably the last thing you feel like when you've got a cold.

For centuries, milk has been blamed for increased mucus production – and in turn a range of other conditions like asthma and snoring.

But while many people swear milk produces mucus, the effect can't be explained by science, says allergy specialist Dr Ray Mullins.

A 2005 review of studies concluded that there was no link between milk consumption and mucus production or asthma. In one study, participants infected with the common cold virus reported symptoms of increased in mucus production after drinking milk, but when their mucus production was actually measured there was no statistical difference. In another study, there was no difference in the sensation experienced between drinking soy milk and cow's milk.

This doesn't mean people don't experience the sensation, says Mullins, but rather that there is no actual increase in mucus production.

He puts the sensation down to the texture and viscosity of milk, and notes that most people do not report similar effects with other dairy products such as cheese.

Mullins says that a sensation of sticky mucus can be caused by many medications that dry out the mouth and throat, particularly in the elderly, as well as viral infections or allergies such as hay fever, but it's rarely caused by diet.

And while many people call the mucus-milk phenomena an allergy, it's not, he says.

True cow's milk allergy is rare in adults. About one to two per cent of children are allergic to cow's milk. They tend to grow out of this by the time they are teenagers – often earlier – and the symptoms are severe, says Mullins.

"A food allergy hits you like a Mack truck," he says, adding that symptoms of cow's milk allergy such as rashes, vomiting and breathing difficulties hit within the first 15 minutes to hour.

Lactose intolerance, in contrast, can cause diarrhoea and nausea or bloating, but it doesn't cause either rashes or snotty noses, says Mullins. It is caused by a lack of the enzymes needed to digest the sugar lactose, and is common in people from an Asian background and about one in 30 Caucasians are also affected.

Mullins says that people who believe dairy products cause an increase in mucus production could try an elimination diet, although in his experience the results are "disappointing".

But he warns that taking people, especially children, off dairy products in the long term can have serious nutritional consequences and is inadvisable.

If you do suspect you or your children have a food allergy, it is important to confirm the diagnosis, he advises. Long-term dietary restrictions should not be implemented without supervision by a dietitan and medical advice, and must include nutritive supplementation in the form of an alternative formula for babies and calcium supplements for older individuals.