Blocked passages

Dairy products have long been accused of increasing nasal and lung congestion. So should you drink milk if you're feeling bunged up?

- Jennifer Bowden

Question: I believe it's advisable to avoid dairy products if too much mucus is a problem. Are some dairy products worse than others? Should I take calcium supplements to make up for any deficiency caused by not having any dairy products?

Answer: Dairy-milk consumption has long been blamed for increasing upper-respiratory tract mucus production. Indeed, the first mentions linking dairy to mucus date back to a 12th-century Jewish physician. Last century, American paediatrician Benjamin Spock, in his world-famous book on infant care, further fuelled this belief. Despite this long history, quality research on the subject was, until recently, relatively limited.

Milk and milk products, such as cheese and yogurt, are valuable sources of dietary calcium, which helps to build strong bones and teeth. They also offer a valuable source of protein, some carbohydrates, fats, essential vitamins such as vitamin A, B2 and B12, and minerals such as zinc. So, there are good nutritional reasons to include dairy products in your diet or to find replacement foods that provide comparable nutrients.

Given the benefits of dairy product consumption and the relative scarcity of good research about dairy and mucus production, many clinicians have tended not to support the adoption of a dairy-free diet to reduce this bodily secretion.

However, in 2018, researchers from Hertfordshire, England, published their findings from a clinical trial investigating the effect of dairy on mucus production. Notably, this trial was double-blinded, meaning neither the participants nor the researchers knew who was receiving dairy products or such the non-dairy replacements as soya milk.