March 2, 2020

Milk has been a cornerstone of childhood nutrition for as long as one can remember. Our children are expected to drink milk at home, in school and at restaurants. The positive health benefits of milk have been touted by the dairy council and the federal government for years. Is this propaganda or rooted in science? What does the data say? Do we really need milk after we stop breastfeeding? Is there a logical precedent evolutionarily for this belief of need? Not all physicians agree that it is that good or even necessary for all. I am steadfastly in this camp along with Frank Oski and many others that have looked over the data.

What is the real deal with milk from the various angles of health? As luck would have it, this past month Walter Willett, MD from the Harvard School of Public Health published an excellent article entitled "Milk and Health". (Willett W. et. al. 2020) Over the course of this article set we will dissect his article and other research published to date. However, before we hit the literature, let us look at what is happening on the ground in clinic.

Currently, it is the year 2020 and human physiological dysfunction is changing faster than medical research can keep pace. Childhood food allergy and intolerance is on the rise and parents are rightfully getting frustrated with both sides of the debate regarding food avoidance. Children cannot have peanut butter sandwiches at school or camp anymore where they were once ubiquitous. That being said, avoidance is only logical as many parents are living with the dread fear of anaphylaxis (a severe food allergy) and death if their child is exposed to this food antigenic trigger by accident. Within one month of being born, thousands of babies are developing eczema and milk protein induced intestinal inflammation. Year over year, this is occurring at ever increasing rates. The root cause of this problem is still under intense investigation, but believed to be multifactorial including intestinal permeability/dysbiosis, immune dysregulation, micronutrient insufficiency, host genetics, chemical/toxin exposure and much more.

I have personal experience with cow milk protein intolerance as my daughter had classic milk protein intolerance at 2 months of age. She was purely breastfed. Somehow she still developed eczema, colic and green bloody stools. My wife's sole intake of dairy was cheese on her salads a few times a week. This is not a large protein volume, yet, the cow milk protein, casein, was passing through her breastmilk to my daughter and causing an intense self destructive immune reaction in her intestines as well as her skin, brain and nasal passages. It was eye opening to say the least.

My wife promptly removed all dairy from her diet. Within one week my daughter was symptom free. Since those unsavory days, my daughter has healed her permeable gut and can now tolerate low volumes of dairy as cheese without issue. She still self selects to avoid milk and yogurt because she doesn't like them, but loves cheese. Some things just taste too good.

These days this story is increasing in frequency and severity at our office at a faster pace than I ever would have imagined. It is a rare week that goes by that I am not counseling a family to put their child on a four week dairy elimination challenge trial for dairy sensitivity or worse, a full forced long term avoidance for true IgE mediated food allergy.

Let us first differentiate the major types of food reactions from a dairy perspective. There are three major types: cow milk protein intolerance, allergy and also lactose intolerance.

First, lactose intolerance is the inability of the body to metabolize the sugar in milk called lactose. This intolerance is based on the lack of production or function of the enzyme lactase. Roughly 65% of humans on the planet have reduced lactase function after infancy (NIH website). It is more common in people of African and Hispanic descent than Caucasion Europeans. The deficiency also increases with age in all humans.The symptoms of lactose intolerance are bloating, flatulence, cramping, diarrhea and vomiting. If you think that you have these symptoms after drinking milk, then you should refrain from milk for a few days and rechallenge your system with a glass of milk. If the symptoms return, then avoidance of milk is a good idea. These individuals can alternatively consume lactose free milk without suffering any symptoms. They can also take an enzyme supplement that contains lactase to achieve the same effect. The deficiency of lactase is not known to be associated with any negative long term disease risk. It is basically a situation where consuming the lactose sugar causes discomfort.

Second and third on the list are two immune mediated reactions to the proteins of cow's milk. First, cow milk protein allergy is an IgE antibody mediated immediate reaction to a cow milk protein that can cause severe anaphylactic reactions. Second, cow milk protein intolerance is a slower, hours to days, IgG or IgG4 subclass immune reaction to the protein. The two main proteins are whey and casein, and an individual may be allergic or sensitive to either or both, however, most react primarily to casein. The casein is the curd that forms when milk is left to sour, and the whey is the watery fraction which is left after the curd is removed. The symptoms can overlap between both types of reactions. The speed of the reaction is the differentiator.

If the allergic reaction is immediate and involves any part of the mouth, stomach or airway or other anaphylactic symptoms, strict avoidance and injectable epinephrine in case of accidental exposure are a must for safety.

Symptoms of cow milk protein intolerance: Colic, diarrhea, gastroesophageal reflux/vomiting, eczema, chronic nasal stuffiness, recurrent sinusitis/ear infection, wheezing, coughing, failure to thrive and bloody stool. Early recognition of these symptoms can save a child many courses of unnecessary antibiotics, reflux medicines and general pain. It is paramount to think of the root cause of the illness and not seek the bandaid approach of drug suppression of symptoms in these young children.

Avoidance of all dairy is the best treatment. The likelihood of resolution of the allergy or casein protein sensitivity improves with every year of life. Unlike peanut allergy, most milk allergic children outgrow the allergy by 6 years old. Many but not most IgG sensitive children maintain the intolerance for decades.

Now that we have looked at the reasons to avoid dairy if you have a concern, what about for everyone else? Next Week!

Milk, it may not do your body good,

Dr. M

Willett NEJM Article