Does Dairy Increase Mucus Production?

Does Dairy Increase Mucus Production?

Mucus is produced by cells within the nose, sinuses, and lungs. It moves towards the back of the throat where it is then swallowed (eek!) Mucus contains antibodies to help protect from infection, and is made up of salt, water, and other proteins which allow it to collect particles of dirt. During colds, more of this mucus is produced and becomes thicker – it is then known as phlegm. When this phlegm becomes thick and dry, it can not only be hard to clear, but can also be irritating to the throat. For centuries, a common belief has been that dairy (especially milk) increases mucus production. Some people complain that when they drink milk or other dairy items, their throat feels coated and the mucus in their throat feels thicker which then makes it more difficult to clear (“Milk, Mucus and Cough,” 2015).

There are several blog and article posts from non-reputable sources that talk about “x” number of foods which cause “excessive mucus” or that cause “congestion,” and not surprisingly, dairy always wins a spot on that list (and even makes it towards the top). So, what does the literature say?

The research on this topic is scarce, and much dates back to the 1990’s. In one study investigating the widely held belief that “milk produces mucus,” 60 participants were infected with the common cold and lived communally over ten days. Nasal secretion weights were obtained through the use of tissue collections, which the subjects would seal into a bag immediately after use. The amount of milk consumed a day was between 0-11 glasses. Twenty-two percent of these participants believed that milk increased phlegm/mucus production and 27.5% overall reported the practice of reducing milk during times of the cold. Although there was a trend for cough with increasing milk & dairy product intake, the results were not statistically significant. They found no relationship between intake of dairy products and the weight of nasal secretions. Interestingly, those who held the belief that “milk makes mucus” or practiced reducing milk intake with colds reported significantly more cold and congestion symptoms, but no increases in nasal secretions. This could have resulted from the “nocebo effect” where the participant’s responses may have been influenced by their initial thoughts of dairy affecting mucus production (Pinnock & Colleagues, 1990).

To tease out the “nocebo effect” a second study trial randomized 125 participants by giving them either dairy milk or soy milk, which was indistinguishable with chocolate milk flavoring. From both groups, participants reported that their saliva felt thicker and they felt as if a “coating” was formed over their mouth, however, neither beverage seemed to affect symptoms like coughing, postnasal drip, sinus congestion or difficulty breathing. The authors concluded that the effect which was measured was not specific to cow’s milk since it was also produced by the soy beverage, which then indicates a possible correlation to consistency of a beverage (Pinnock CB, Arney WK, 1993).

Asthma is characterized by the over-production of mucus which obstructs the airways. A literature review by Wüthrich and colleagues looked at the association that milk has on the development of asthma and mucus production. The authors concluded that abstaining from dairy products due to the belief that it may induce mucus production and exacerbate asthma symptoms is not supported by the body of research evidence. They also concluded that those with asthma need not avoid consumption of dairy products to control their symptoms (Wüthrich & Colleagues, 2005)

Milk and dairy products provide many essential nutrients that benefit our health, such as calcium which supports bone health, protein which builds and repairs muscle tissue along with supplying our body adequate energy, and potassium which helps maintain a healthy blood pressure. Restricting milk and dairy in children may also result in restricted growth and bone development as milk and milk products are the main source of calcium in the diet. The body of research is from over twenty years ago, and although the researchers made conclusions, newer studies may provide new findings. However, from what is known now, it is not necessary to eliminate dairy from your diet if you are concerned about mucus production. If you are aware of the foods that bring your body discomfort, then limiting their consumption may be of benefit. If there are any foods that you might be unsure about, speak with your doctor and registered dietitian to see if experimenting with substitutes is a good idea.

References

• Mendez, Bianca. “15 Foods That Can Make You Congested.” Eat This Not That, Eat This Not That, 9 Oct. 2017, www.eatthis.com/foods-that-make-you-congested/

• Fraser, Carly. “12 Foods That Cause Excessive Mucus In The Body (and 14 Foods That Eliminate It!).” Live Love Fruit, 2 Feb. 2018, livelovefruit.com/foods-that-cause-excessive-mucus/.

• “Milk, Mucus and Cough.” Australasian Society of Clinical Immunology and Allergy (ASCIA), 2015, www.allergy.org.au/patients/food-other-adverse-reactions/milk-mucus-and-cough.

• Pinnock CB, Arney WK: The milk mucus belief: sensory analysis comparing cow’s milk and a soy placebo. Appetite 20:61–70, 1993

• Pinnock CB, Graham NM, Mylvaganam A, Douglas RM: Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2. Am Rev Resp Dis 141:352– 356, 1990

• Wüthrich, B., Schmid, A., Walther, B., & Sieber, R. (2005). Milk Consumption Does Not Lead to Mucus Production or Occurrence of Asthma. Journal of the American College of Nutrition, 24(Sup6). doi:10.1080/07315724.2005.10719503