Milk and dairy products potentially cause trouble for a growing number of people in the population, yet milk is touted as a necessary health food with the USDA recommending a daily intake of 3 cups of nonfat or lowfat milk for adults and children 9 and older. As consumers, we are presented with an ever increasing number of choices: conventional, hormone-free, grass-fed, organic, unpasteurized, pasteurized, vat pasteurized, ultra-pasteurized, homogenized, unhomogenized, Jersey cow milk, goat’s milk, nonfat, 1%, 2%, paper, plastic, glass…the choices are dizzying!
The posts for the next two months are dedicated to untangling the web of confusion surrounding milk and dairy products and health issues surrounding them. What’s the difference between lactose intolerance, milk allergy, and dairy intolerance? Should you drink milk, and if so, what kind?
We all know that milk can be nutritious, full of protein, fat, vitamins, and minerals, but as you might have guessed, it’s a complicated story because not all milk is created equal.
For those of you who have been keeping up with me, you know that I like fat, well good fat, that is. Fat-soluble vitamins, A, D and K are completely lacking in skim milk as these vitamins have been removed with the fat. Those vitamins are necessary to properly metabolize and absorb the calcium found in milk. Additionally, A 2007 study done by the Harvard School of Public Health found a substance found in dairy fat that reduces the likelihood of Type 2 diabetes. Not only are you not getting those nutrients when you drink nonfat or lowfat milk, but these milks often have nonfat milk powder and dry milk solids added to compensate for the lack of fat. These dry milk products are a source of oxidized cholesterol, which is implicated in inflammation and cardiovascular disease.
Many who are intolerant of dairy may be unaware. Symptoms of dairy intolerance can be fairly obvious such as bloating, pain or cramping in the belly, diarrhea, vomiting, nausea, or rashes, but they can also come in less obvious forms, such as flu-like symptoms, runny nose, congested sinuses, excess mucus formation, or asthma-like symptoms. Even more subtle symptoms include lethargy, joint pain, brain fog, and difficulty in concentration. Epidemiological studies have even implicated dairy in heart disease, Type 1 diabetes, autism and schizophrenia.
Milk has a number of different components, so before we can understand the complexities behind various types of milk intolerance, we must look at what it’s made of.
Milk solids contain lactose, a milk sugar, proteins, minerals, acids, vitamins, and enzymes.
So which of these components can your body react to?
Lactose is the main carbohydrate that is found in milk. Human milk is actually much higher in lactose than cow’s milk, but the production of lactase, the enzyme that breaks down lactose, starts to decrease at the age of 2 and sometimes even earlier. According to the National Institutes of Health, an estimated 65% of the human population has decreased ability to digest lactose after infancy. This makes sense, in light of the fact that most animals begin to wean from mother’s milk after infancy.
Humans, smart as we are, have taken it upon ourselves to drink the milk of other animals. The ability to produce lactase into adulthood, known as lactase persistence, varies widely with genetics, mostly relating to the length of time various populations have had milk in their diets. For example, an estimated 90% of East Asians while just 5% of Northern Europeans are lactose intolerant.
Compromised gut health is another important factor that may contribute to lactose intolerance. Epithelial cells that line the intestines are producers of lactase, so when they are damaged as in the case of leaky gut, they are unable to perform their normal functions. Symbiotic bacterial gut flora, including the species Lactobacillus, is also a producer of lactase, so a person may experience lactose intolerance if he/she has dysbiosis, an imbalance in gut bacteria.
Allergies are immune responses to proteins, so milk allergies are to either casein or whey, the milk proteins. Most people with milk allergies are allergic to casein. Like other allergies, those to milk proteins elicit an acute response such as rash or hives, difficulty breathing, diarrhea or vomiting, or an elevated pulse. It’s likely that if you are allergic, you already know.
However, dairy intolerances can be more insidious because symptoms aren’t as obvious. Again, a leaky gut is a contributing factor—it allows proteins and other particles to enter the bloodstream where they’re not supposed to be and the immune system responds accordingly.
To complicate matters further, not all casein proteins are created equal…
There are actually a handful of casein proteins, the most predominant being beta-casein. Heirloom breeds of cows produce a certain variant of beta-casein and are known as A2. About 5,000 years ago a mutation in this particular gene occurred, and more modern-bred cows, such as the ubiquitous black-and-white spotted Holsteins that produce the mutated beta-casein, are known as A1 cows.
According to the EPA, the United States dairy herd is composed of over 90% Holsteins, about 7% Jerseys, and 2% Ayrshires, Guernseys, Brown Swiss, and Milking Shorthorns. The Holstein cow has become the most popular dairy cow in this country due to its high milk production and ability to grow quickly in intensive, grain-fed conditions without pasture.
Ok, so what does this all mean for us??
The mutation in A1 beta-casein causes it to be digested into beta-casomorphin 7 (BCM-7), an opioid. BCM-7 has been shown to increase systemic inflammation and has been implicated in a variety of neurological disorders, such as autism and schizophrenia, as well as cardiovascular disease, Type 1 diabetes, and autoimmune diseases. BCM-7 also selectively binds to epithelial cells, increasing mucus secretion. Opioid receptors are found all over the central and peripheral nervous systems as well as in the gut, so as you can imagine, the effects of BCM-7 can be very diverse and widespread, especially in the presence of compromised gut health. This explains the wide variety of symptoms and the diversity of the severity of symptoms in those that don’t tolerate dairy well, as well as anecdotal evidence in which such symptoms are mitigated in the presence of a dairy-free diet.
A2 cows produce a form of beta-casein that does not get metabolized into BCM-7. Jersey, Guernsey, and Brown Swiss cows produce predominately A2 beta-casein but are not as popular because of their lower milk production and their necessity to be on pasture. Jersey cow milk is additionally prized due to its higher fat content and creaminess. Goat milk and human milk also contain A2 beta-casein, hence some people’s ability to tolerate goat, but not cow, dairy products.
European cows are predominantly A1, with the exception of those in France. Interestingly, the French, known for their high quality dairy products, have eschewed the modern A1 cows, for reasons of taste, so most of their dairy cows are A2. African and Indian cows are also predominately A2.
For more information on this topic, refer to A Devil in the Milk, by agribusiness and farm-management professor, Keith Woodford.
The great news is that the milk that is best for us is also best for the cows and for our environment (no surprise). The minority dairy producers who choose to raise heirloom cow breeds, such as Jersey and Guernsey, do so to obtain a higher quality product that supports sustainability and animal welfare. According to St. Benoit Creamery, a Northern California milk producer whose herd is composed of pasture-raised Jersey cows, Jersey cows produce 30% less milk compared to their Holstein brethren. In the words of the EPA, “[p]asture-based systems often strive to optimize rather than maximize milk production.” Another benefit to buying milk from these companies is getting your milk in reusable glass bottles, another indication of their commitment to sustainability.
For those of you who are local, here is a guide to some local dairies and their cow breeds:
Next month, we will tackle various milk-production processes and how they affect the milk before it reaches your lips.
Read Milk: Does it Do a Body Good? Part 2 now.
Give it a Try!
This month's recipe is a simple, delicious dessert utilizing our honored ingredient. Enjoy!
California Bay Laurel Custard
2 cups whole milk
1 California bay laurel leaf (or regular bay leaf if not available)
pinch of sea salt
2 egg yolks
3-4 Tbs maple syrup
nutmeg for garnish
Preheat oven to 300º. Put milk, bay leaf, and pinch of salt into a saucepan over medium heat until it just reaches a low simmer. Take off the heat and let the bay leaf steep for 10 minutes. Remove the bay leaf.
Meanwhile, in a medium sized bowl, whisk the eggs and yolks with the maple syrup. Slowly and gradually pour the milk into the egg mixture, whisking all the while until the milk is incorporated.
Divide the custard into 6 ramekins. Place the ramekins into a heat-proof pan (a casserole or roasting pan works well) and fill the pan with water until the level of the water comes half way up the sides of the ramekin. Place the pan with the ramekins and water into the oven and bake until the custard is just set, about 30 minutes. The custards will still be slightly jiggly. Remove the ramekins to a cooling rack, and let cool for at least 2 hours before serving. Dust with freshly grated nutmeg.