Is Milk-Induced Mucus A Myth?

Expert says there is “no evidence” that dairy increases mucus production from the lungs.

An expert in children’s respiratory diseases says that there is no need for children with asthma, cystic fibrosis, or the common cold to avoid dairy products. In a research review published in Archives of Disease in Childhood, Dr Ian Balfour-Lyn, a consultant at London’s Royal Brompton Hospital, argues it is a myth that milk boosts phlegm production and worsens respiratory conditions, and says parents shouldn’t avoid giving “this nutritious and bone-strengthening foodstuff to children with asthma, cystic fibrosis, or respiratory infections”.1

He writes that the notion that milk might generate excess phlegm (and that chicken soup alleviates it) began in 1204, with a treatise on asthma by Moses Maimonides, who was a court physician. This belief, he says, was later perpetuated by children’s health guru Dr Spock in his 1946 best seller Baby and Child Care.

Weakened bowel integrity

Citing studies back to 1948, Balfour-Lyn says there is no evidence to support the belief, although one (yet to be proved) possible explanation involves a protein produced by the “breakdown of certain types of milk, which is known to boost the activity of a gene that stimulates mucus production”.