Should You Avoid Dairy When You Have a Cold?

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"Don't eat dairy when you have a cold." "Milk creates mucus." Chances are good you have heard one of these statements—or some variation of them—before. Many people believe that dairy products create more mucus when you are sick. But is there any proof? Is there really any evidence to back up this commonly held belief?

Mucus and Colds

Colds, the flu, and other upper respiratory infections make us feel pretty crummy.

They cause all sorts of symptoms like a runny nose, congestion, coughing, sore throat, and sometimes fever. Many of these symptoms occur in response to the virus invading our bodies. Essentially these symptoms are a defense mechanism—a way that our bodies try to get rid of the virus that is making us sick. Increased mucus production is one way that your body fights infection, and even though it's no fun to deal with, it actually does serve a purpose. 

So, if your body is creating mucus to rid your body of an infection or another foreign invader like an allergen, could dairy products have any bearing on the amount? As it turns out, probably not.

What Does the Science Say?

There have been several studies designed to test the theory that dairy products increase mucus production. The outcomes of these studies show that it doesn't. Drinking milk or eating dairy products does not create more mucus.

When people are asked how they feel if they are congested and then consume dairy products, they often report feeling like their mucus production increased. However, the scientific proof doesn't back up these self-reports. 

One study measured mucus production when people blew their noses into tissues and weighed them.

Another study tested how people felt after drinking either cow's milk or soy milk, and the results were the same. The participants did not know which type of milk they were drinking but reported very similar symptoms. Both of these studies concluded that there is no evidence that dairy has an impact on mucus production. 

Why Do People Believe This?

Drinking milk can make mucus feel thicker and leave a temporary coating in the mouth and throat. It's possible these effects led to the belief that dairy products—and milk in particular—increases mucus production when it actually doesn't. You may feel like you have more mucus in your throat when you drink milk because it feels thicker, but there isn't actually any more of it there.  

In some cases, people who actually have an allergy to milk or dairy products may experience an increase in mucus production as a part of an allergic reaction. However, most people who have a true dairy allergy experience symptoms such as hives (rash), vomiting, stomach pain, bloody stools, or anaphylaxis when they consume dairy products.

What Can I Do About Mucus?

So, now that we know dairy products don't have any bearing on mucus production, you may want to know what you can do to help when your nose and head feel congested. There's really no reason to avoid dairy products, but there are other things you can do. 

  • Drink More Water. Staying hydrated and drinking plenty of water will help thin the mucus and allow it to drain more easily. Most people don't drink nearly enough water in a day and you will need even more when you are congested. Just try to keep water with you all the time and drink it as often as you can. 
  • Run a Humidifier. Similar to how drinking water can thin the mucus, running a humidifier will help as well. Extra moisture in the air, especially when you are sleeping at night, will help keep your airways from getting dry and irritated. It will help loosen congestion so it can drain more easily as well. 
  • Try OTC Medications. Medicines like decongestants and expectorants can help with congestion by breaking up the mucus and allowing it to drain out of your sinuses. 
  • Use Saline SpraySaline sprays are available at most any grocery store or pharmacy and are a great way to loosen mucus in your nose and sinuses. These sprays are gentle and easy to use. They contain no medicines, so they are safe and have no side effects. 
  • Try a Sinus Rinse or Neti PotSimilar to the saline spray, these products use a saline solution to rinse out your sinuses. If you are congested or are dealing with a lot of mucus, these are a great option to clean some of it out. It's important to always use distilled or previously boiled water that has been cooled if you are making your own saline solution. Never use straight tap water or well water. They could be contaminated or contain organisms that can cause serious infections. 

A Word From Verywell

There are a lot of "old wives' tales" out there that people believe because they heard them for as long as they can remember. If everyone you know tells you something is true, you tend to believe it is. But when it comes to science and medicine, we have found that a lot of those commonly held beliefs aren't as true as many people believe. So now you know, dairy doesn't create mucus, so you don't have to avoid the ice cream if you have a cold. 

Sources:

Milk & Dairy Allergy. ACAAI. http://acaai.org/allergies/types-allergies/food-allergy/types-food-allergy/milk-dairy-allergy. Published January 12, 2015. 

Pinnock CB, Graham NM, Mylvaganam A, Douglas RM. Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2. Am Rev Respir Dis. 1990;141(2):352-356. doi:10.1164/ajrccm/141.2.352.

Wüthrich B, Schmid A, Walther B, Sieber R. Milk consumption does not lead to mucus production or occurrence of asthma. J Am Coll Nutr. 2005;24(6 Suppl):547S - 55S.

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