Initially, the team behind the study was trying to debunk the link between dairy and phlegm.
"I was sceptical and didn’t believe it was real," Adam Frosh, consultant ear, nose and throat specialist at the Lister Hospital in Stevenage, Hertfordshire, told the Daily Mail. Adding, "The results were the opposite of what I was expecting."
On day three, they half of the participants were given full-fat cow’s milk , with the others were given soya milk for the rest of the week.
For the study, 26 men and 82 women who suffered from of increased mucus secretions were out on a dairy-free diet for six days.
The results showed a reduction in mucus levels in all the volunteers in the first two days. However, over the course of the week, those that drank soya continued to feel better, while those who drank cow's milk did not and the symptoms grew worse.
"This was quite a big effect in a relatively short space of time," Frosh revealed.
"It’s reasonable to conclude that anyone who feels milk increases their mucus production should consider reducing their dairy intake, or try a dairy-free diet, to see if it improves their symptoms," he further explained.
One of the reasons milk has such a strong effect is because it contains beta-casein A1, which is a protein that helps promote mucus production.
The findings were originally published in the journal Laryngoscope....