Cow’s milk has a long history as part of the standard western diet, and other than meat is often the major dietary source of protein. Milk, for many, is also the major dietary source of calcium, which presents many problems of it’s own, resulting from the low availability of the calcium in milk. While the problems with relying on milk for calcium are discussed in other articles, it is the protein (casein) that is the source of most of the problems with milk and the reason we don’t recommend it’s use in our clinic.
Casein. The Second Evil Protein
We talk a lot about gluten; the damaging protein found in wheat and many cereal or grain products. Gluten’s partner in crime is a protein known as casein. Casein has a very similar structure and very similar effects to gluten. The major source of casein in the diet is milk, particularly cow’s milk. As with gluten, common symptoms of casein intolerance and allergy can include:
- diarrhea, constipation, gas, and bloating,
- headaches and migraines,
- dermatitis, skin allergies, and eczema,
- in extreme cases, anaphylaxis and even death.
Casein in milk exists in different forms. Most evidence of allergies and adverse health problems has been based on the form of casein in most milk produced by commercial dairy cows in Australia. Some evidence suggests that milk with the A2 form of casein, does not create these problems (1). Milk containing A2 caseins is called A2 milk and can be found on some supermarket shelves.
Casein is also found in breast milk. However, casein in human breast milk is typically about 0.2%, while casein in cow’s milk is > 4% (2). This may well explain why allergies and negative side effects don’t result from human breast milk, unless the mother’s diet is high in cow’s milk products.
Unfortunately, casein also makes the rounds as a food additive disguised under a variety of different names. To truly remove casein from the diet requires an eagle eye and close inspection of all food labels. Some common ingredients to watch for on food labels include:
- caramel coloring,
- brown sugar flavoring,
- natural chocolate flavoring,
- Bavarian cream flavoring or coconut cream flavoring
- magnesium caseinate,
- artificial butter flavor,
- malted milk margarine.
Milk’s Effect on IBS, IBD & Allergies
When talking about milk, it’s important to also talk about irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). While it may often be controversial, milk is a common culprit in these diseases. Studies have shown that patients with inflammatory bowel disease, most notably ulcerative colitis, exhibit a much higher level of antibodies to milk proteins than patients without colitis (3). Higher levels of antibodies are a sign of constant immune activation and subsequent inflammation being caused by the foreign proteins in milk.
What Makes Cheese, Yoghurt & Butter Okay?
Humans have, over time, found ways to make cow’s milk much safer on the human gastro intestinal tract. These processes usually revolve around separating the fat and protein component, or converting the protein into something that is not as harmful to our bodies.
It is important that anyone with active symptoms of IBD such as diarrhea, constipation, or blood, and mucous in the stool, avoid any form of milk and dairy product, even cheese, cream, yoghurt, and butter, until they are symptom free.
If you’re like me and enjoy soft cheeses such as camembert and bree after a good meal you’re in luck. Cheese making involves not just curdling, or souring, of milk, but also the introduction of a group of enzymes known as rennet. One of the enzymes in rennet is a proteolytic enzyme, or an enzyme that acts on proteins, this causes coagulation of the milk due partly to structural changes that occur in the proteins.
These enzymes continue to work long after the initial curdling and are what gives aged cheeses their distinctive tastes and appearance. For this reason, we recommend aged, soft cheeses over younger, harder cheeses. Good examples include camembert and bree.
When milk is left to stand it naturally separates into a high fat, somewhat thicker layer, known as curds and a clearer, liquid, layer known as whey. Cream is made from the higher fat, curd layer of milk. Unlike cheese, there is no enzymatic reaction to the casein portion of curds so some particularly sensitive people can still experience adverse reactions to cream. Although this is uncommon, it may happen in the early stages of recovery from IBD.
Once symptom free, cream however is typically safe to consume. The much higher fat to protein ratio, and the smaller quantity in which cream is used means that only small amounts of casein are ingested. It has also been suggested that the coagulation of casein in cream ensures it spends longer in the stomach where it is exposed to pepsin, one of the digestive agents responsible for the break down of proteins.
Made largely by churning of cream, butter falls into much the same category as cream. While casein is still present in butter there is typically less than 1g of protein per 100g of butter making side effects from the consumption of butter very rare indeed.
Owed to both the small amounts of butter consumed and the small amount of protein in butter we rarely find it necessary to exclude butter from the diet. Butter often makes a valuable addition to the diet, particularly in cases of inflammatory bowel disease, as a dietary source of butyric acid. Butyric acid is the major fatty acid fuel source for cells that line the colon and can help alleviate reduce inflammation associated with colitis and Crohn’s disease.
Yoghurt is a fantastic, healthy, snack. If made properly, yoghurt also contains many beneficial microorganisms that can help maintain the correct balance of intestinal flora.
Much like cheese, making yoghurt involves the introduction of microorganisms. In yoghurt’s case these are bacteria including lactobacillus and bifidobacteria. While these bacteria primarily operate on the milk sugar lactose, the resulting lactic acid works on the proteins in the yoghurt and is what provides the characteristic taste.
It is the conversion of these proteins by lactic acid that helps to convert the casein making yoghurt safe to consume.
 Woodford. Devil In the Milk – Illness, health and politics, A1 and A2 milk.Craig Potton Publishing,2007
 Neville. MILK SECRETION: AN OVERVIEW.,1998
 TAYLOR and TRUELOVE. Circulating antibodies to milk proteins in ulcerative colitis..British Medical Journal,1961.