top of page
  • Writer's pictureDr. Brian Lum

Why Do I Feel Sick When I Eat Dairy?

Updated: Jul 24, 2023

There are many reasons why you may feel sick when you eat dairy.

Common symptoms of dairy intolerance include nausea, bloating, hives, headaches, sleeplessness, anxiety, acne, and joint pain.

These symptoms are usually written off as 'lactose intolerance' and lifelong dairy avoidance is recommended.

This is unfortunate for two reasons - firstly, lifelong abstinence from dairy is usually not required after the underlying cause of dairy sensitivity is found.

But the most important reason is that by labeling the cause of these symptoms as a generic 'intolerance' it leaves the true cause of dairy intolerance to remain present or to get worse.

blue background with dairy products with text overlay Why Do I Feel Sick When I Eat Dairy? Dr. Brian Lum, DC, IFMCP

Causes of Dairy Intolerance

A common cause of feeling sick when you eat dairy is an underlying bacterial infection. That bacterial culprit can be Streptococcus, which is the same bacteria that causes strep throat. In this case, Streptococcus inhabits the liver and intestines.

Staphylococcus is also a common culprit in those who experience symptoms from dairy as are parasites. Both parasites and Streptococcus are relatively easy to check for using testing.

Mold is also a common cause of dairy sensitivity as well as a wide range of other symptoms.

One patient I had with dairy sensitivities was a 31-year-old woman who only notices nasal congestion or tension in her forehead the night after she has eaten some dairy.

She has other symptoms including migraines around her period, frequent waking up in the middle of the night, low energy, the feeling of blocked ears, and high levels of general anxiety.

Because her 'secondary symptoms' were written off by her primary care doctor as 'hormonal' and were not considered important, this patient thought she just had to learn to live with these symptoms.

When the patient ate dairy, elements in the dairy products were feeding her Streptococcus infection so it grew quickly.

That larger infection produced waste products which caused inflammation - making her feel sick and contributing to her long term 'secondary' symptoms.

Note that these symptoms can occur right after you eat, or they can occur days later and persist for weeks.

After some testing (I ordered testing to be done at her local hospital), I was able to identify a significant Streptococcus infection throughout her intestinal tract as well as Candida overgrowth in her sinuses.

Through pharmaceutical-grade herbal supplements and diet and lifestyle modifications, we were able to completely get rid of both infections in a matter of weeks. Her secondary symptoms were fully resolved a few weeks after that.

Dairy is Mucus-Producing - Why That Matters

When your body consumes dairy, you produce excess mucus. That is why many people experience a stuffy nose or a sinus headache after consuming dairy products. Mucus is produced not only in your sinuses but all along the gastrointestinal tract.

Too much mucus in the intestines causes gastrointestinal symptoms like stomach pain, bloating, and gas.

If you already have an underlying infection your body is producing excess mucus. This excess mucus has an important purpose as it traps bacteria and potential threats and escorts them out of your body.

So if you are highly reactive to dairy, it could be because you've already reached your upper limit of mucus in which your body can function without producing symptoms. It also indicates that you have an underlying infection or imbalance that needs to be addressed.

Lactose Intolerance vs. Dairy Intolerance

A way to see if your symptoms fall under the category of lactose intolerance or dairy intolerance is to classify your reaction based on dosage.

Generally, in the case of lactose Intolerance, you would react to dairy in whatever amount you eat. Even a very small amount would make you feel sick.

In the case of dairy intolerance, (caused by an underlying infection, parasite or other cause) symptoms are dose dependent.

Which means that you may be able to get away with a sprinkling of cheese or a sip of milk but the more you have, over a series of hours or days or weeks - the worse your symptoms will get.

With dairy intolerance, the level of inflammation can be relatively low, but it is long term. Symptoms resulting from these low levels of inflammation are regarded as 'low level' and usually disregarded.

Symptoms like poor sleep, anxiety, poor digestion and fatigue can significantly reduce your quality of life but without the use of functional medicine, it can be hard to isolate the cause.

Another thing to keep in mind is that often, lactose intolerance is also caused by an underlying infection or condition!

In the case of both lactose and dairy intolerance it is imperative to get to the bottom of what is going on in your body.

Functional Medicine Treatment For Dairy Intolerance

In most cases of individuals with dairy reactivity it is important to identify what kind of infection you are dealing with (parasitic, bacterial or viral) and where it is.

Most dairy sensitivity-related problems keep coming back because infections are only treated in the intestines.

We will also identify underlying functional problems which make it harder for your body to clear the infection (like low mucus production, adrenal fatigue, thyroid imbalance) and find out how to make your body more resilient on an intrinsic level.

Many of the interventions I prescribe are dietary and lifestyle changes that can significantly reduce symptoms while we get you back on your way to health. All of these are tailored to your specific situation.

Worldwide Online Consultation

As always in my practice, there is never a one-size-fits-all approach. Our hour long new patient appointment will go over your medical history since birth. All of your symptoms, goals and worries are relevant in the development of your treatment plan.

My practice is now 100% online and I can have a consultation with you anywhere in the world. You can read more about an online consultation here.

I can personalize treatment and even work with your primary care physician or order testing if you are out of state or outside of the country.

If you would like to speak with me directly you can schedule a Free 15 Minute Consultation here or call or text my office directly at 913-728-5291.


If you think that you may have a medical emergency, call your doctor or 911 immediately. No action or inaction should be taken based solely on the contents of this information. Nor should you ever delay seeking medical advice or treatment due to the information contained on this Website.


Les commentaires ont été désactivés.
bottom of page