No link seen between milk, mucus buildup

Q. I became concerned after reading that milk can cause the production of mucus, and I eliminated all milk products from the diet of my son, Zachary. I don't want to do anything that would cause him any problems, but I have now gotten into a discussion with my parents over whether I am doing the right thing. What is your take on milk and the milk-mucus controversy?

A.B., Deerfield

A. I have no doubt you are a loving parent and you want to do what's best for Zachary, so let's review the possible connection between milk and mucus production.

There was a study in the February 1993 issue of the journal Appetite that tested for a milk-mucus effect in 169 people, 70 of whom believed that milk produces mucus. The scientists compared milk with a soy-based drink that tasted identical. (They had done a pre-test to establish that people could not identify the different beverages.) They found that there was no difference in the subjects' perception of mucus production. The scientists concluded that it was the sensory characteristics of the beverage -- and not the presence of milk -- that gave rise to the sensation of coating of the tongue and throat.

Skip ahead to December 2005, and a supplement to Journal of the American College of Nutrition focusing on many aspects of the relationship between dairy consumption and health.

One of the articles in this issue reviewed evidence that milk consumption might lead to an increased production of mucus, or that it might contribute to asthma. All participants were prescreened for a milk allergy. The paper concluded that there was no support for a connection between milk and mucus production, or milk and asthma.

I could find no science to support a milk-mucus connection. All this, of course, assumes there is no milk allergy, but this is something you can talk about with your family physician.

The basis for the long-held belief would seem to rest with the normal interaction between our saliva and the characteristics of milk. This mix produces a thickened-fluid sensation in the throat that can be mistaken for mucus. It is important to understand that what gets produced in our throats in this manner is not the same as the production of unwanted mucus in the lungs.

Normally, when we breathe, the air goes into our lungs via the bronchial tubes that branch into increasingly smaller bronchioles. Our air tubes normally have a thin mucus lining, and hair cells that help trap unwanted debris and pass it out of the lungs.

When there is an infection, such as a bronchitis, the mucus layer becomes inflamed, and this can increase mucus production. Excess mucus, also known as phlegm, can collect, and the body attempts to clear it by coughing.

Asthma is a chronic illness in which the lungs become inflamed, usually in response to one or more triggers, and the production of excess mucus in the lungs can play a role in how this disease manifests. These are disease processes, very different from normal drinking and swallowing.

There is no reason to restrict milk or dairy when your child is sick based on the fear that these foods will contribute to mucus congestion.

Milk does contain a number of important nutrients, but it's not essential; you can get all these nutrients from other foods. At the same time, however, there is no denying that milk and other dairy products represent good nutrition in very convenient packages.