Types of Casein
Can you tolerate dairy overseas but not at home?
[Updated May 18, 2015]
Nick was a successful businessman in his mid-30s with a persistent case of eczema. Over the years, he had applied various ointments and prescription creams recommended by a string of dermatologists, allergists and well-meaning friends, all to no avail. When someone suggested a nutritionist might help, he figured it would be another waste of time but he was desperate.
“My skin drives me crazy,” Nick told me. “The irritation is relentless.”
I asked him the usual background questions. When had the condition started? Were there any other diagnoses? Did the symptoms come and go? Had any treatment helped, even a little? And, of course, what was he eating?
His responses didn’t obviously point to a nutritional cause. The condition had existed since college. He’d been tested extensively for allergies, which his specialists assured him were not the culprit. He was fit and ate a variety of healthy foods. He enjoyed wine but didn’t eat many sweets. While cortisone cream relieved the itching temporarily, too much of his skin was affected to use it long term. He applied the prescription cream only when he couldn’t bear the discomfort.
“I’m in perfect health, other than itching all the time and looking like a lizard,” he quipped.
“Has your skin cleared even for a short time at any point?” I persisted.
It turns out it had. Twice when Nick had gone to France, his skin cleared. His doctors had long ago attributed the remissions to vacation stress reduction, so he thought the information was insignificant. I wasn’t so sure.
Casein sensitivity is easier to spot when people have symptoms immediately after ingestion, such as stuffiness or stomach distress, rather than a delayed reaction like eczema.
More About Milk
Over the years, different people have reported to me that they could drink milk or eat dairy products in France, India or Australia but developed symptoms when drinking it in the United States. One woman who worked at an international bank sported a swollen, beet-red face only when she was stationed here, not when she was home in India. We discovered the problem was American dairy products. She could eat all the dairy foods she wanted in India but reacted fiercely when she drank milk produced in the States. At first, I theorized the culprit was something in the cow’s feed. Now I believe the irritant is the different milk proteins produced by different breeds of cows.
All mammal milks contain casein in different concentrations. Eighty percent of the protein in cow’s milk is casein. Human milk is less concentrated, with only 20 to 45 percent casein. Not only does the concentration of casein in milk differ among species and breeds, the type of casein varies, as well.
There are two main types of casein: A1 and A2. Almost all American, Australian and European (except French) cows produce milk with mostly A1 casein. Cows in Asia, Africa and France produce milk with mostly A2 casein. Goats produce milk with A2 casein in concentrations closer to human milk levels. Because the casein is A2 and there is less of it, some people can tolerate goat’s milk products but can’t tolerate cow’s milk.
Caseins A1 and A2 are exactly the same protein but have one difference in their amino acid sequence. ( In amino acid position number 67, casein A1 has histidine and casein A2 has proline.) In biochemistry, one amino acid difference can completely change how the molecule behaves, including how it’s digested and metabolized.
“I think your problem may be milk sensitivity,” I told Nick.
He had a hard time accepting the theory, as he ate larger quantities of dairy products, especially cheese, when he was in France than when he was at home. Yet he reluctantly agreed to try a dairy-elimination diet for six weeks. As far as he was concerned, the biggest argument for trying the diet was the lack of other alternatives.
Six weeks later, Nick was jubilant about the barely visible traces of eczema—but he was missing dairy. “Does this mean I can only eat cheese in France?” he asked.
Nick could travel to France or Australia (the current center of the A2 milk movement) for all his vacations but there are increasing options available for people in the States. Milk from Guernsey and Jersey cows, as well as camels, yaks, sheep and goats, contains mostly A2 casein. Some small farmers are now selling milk from A2-producing breeds of cows.
For more information about different casein proteins, go to betacasein.org.
Note: Those with lactose intolerance will not benefit from changing casein sources. People with dairy-induced anaphylaxis should not ingest dairy products under any circumstances.
Licensed nutritionist dietitian Kelly Dorfman, author of What’s Eating Your Child?, has 29 years of clinical experience developing nutrition and lifestyle strategies to address complex health problems.