A widely-held myth is that giving children milk could potentially worsen respiratory conditions including asthma and the common cold, because of claims it leads to excessive mucus production in the mouth.
However Dr Ian Balfour-Lynn, a children’s respiratory consultant from London’s Royal Brompton Hospital, has argued that this is not the case.
“While certainly the texture of milk can make some people feel their mucus and saliva is thicker and harder to swallow, there is no evidence (and indeed evidence to the contrary) that milk leads to excessive mucus secretion,” Dr Balfour-Lynn wrote.
“Milk is an important source of calories, calcium and vitamins for children. The milk–mucus myth needs to be rebutted firmly by healthcare workers.”
Arguing his point in the Archives of Disease in Childhood, Dr Balfour-Lynn said the myth that milk might generate excess phlegm comes from a children’s health guru in 1946 - Dr Spock - who brought out a child and baby book, which stated: “Dairy products may cause more mucus complications and more discomfort with upper respiratory infections.”
The theory that milk increased mucus production was based on the idea that a protein produced by the breakdown of certain types of milk is known to boost the activity of a gene that stimulates mucus production.
Balfour-Lynn argued that this process does happen, but it happens in a person’s bowel and therefore could only affect the respiratory tract if a person’s bowel was weakened by infection.
He said milk may feel like it has more volume in the mouth because milk is an emulsion of fat in water, and emulsions mix with saliva. “This could well affect the sensory perception of milk mixed with saliva, both in terms of its thickness coating the mouth and the after feel—when small amounts of emulsions remain in the mouth after swallowing,” he wrote.
Milk is an important source of calories, calcium and vitamins for children. The milk–mucus myth needs to be rebutted." Dr Ian Balfour-Lynn
He continued: “This may explain why so many people think there is more mucus produced when in fact it is the aggregates of milk emulsion that they aware of lingering in their mouth and throat.”
Balfour-Lynn argued that milk is the principle source of calcium for children and adults as well as a good source of several vitamins, and therefore omitting this important calorie source is potentially harmful.
The NHS recommends giving young children at least 350ml (12oz) of milk a day, or two servings of foods made from milk, such as cheese or yoghurt.
They state semi-skimmed milk can be introduced from the age of two, provided a child is a good eater and growing well for their age. Skimmed or 1% fat milk doesn’t contain enough fat, so isn’t recommended for children under five.
The NHS also advises that you can give your child unsweetened calcium-fortified milk alternatives, such as soya, almond and oat drinks, from the age one as part of a healthy, balanced diet.