If you already knew that casein was the main protein in milk, then you’re on the right track. What you probably didn’t know, though, is that there are different types of casein depending on the type of cow that produced the milk. Conventional cow’s milk contains mixtures of A1 and A2 beta casein and research has shown recently that suggests that A1 beta casein is inflammatory. To date, there have been very few studies comparing the effects of A1 and A2 beta-casein on the gastrointestinal system.
Now there is a study showing that self-diagnosed lactose intolerance is likely just a bad reaction to A1 casein. Titled “Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults” it was a randomized, double-blind crossover study with 630 Chinese subjects. Statistics show that up to 90% of East Asian ethnic groups are lactose intolerant. In this study, all of the subjects’ intolerances were self-diagnosed and all subjects were non-regular milk drinkers. The subjects were given 300 mL of two milk products that were identical except that one contained only A2 beta casein protein. They were then monitored for symptoms three times (1 hour, 3 hours and 12 hours) after consuming the milk.
The study found that those who consumed the milk that contained no A1 beta casein protein had significantly less severe symptoms (flatulence, bloating, abdominal pain, stool frequency, and stool consistency) than the subjects who consumed conventional milk that contained A1 and A2 beta casein protein. From these findings, it seems very likely that those with self-reported lactose intolerance are likely suffering from a sensitivity to the A1 beta-casein protein.
I have my own anecdote to share and one of the reasons why I have partnered with the a2 Milk® Company. As a Latino, drinking milk and consuming milk-based products were a way of life. However, one day, I concluded myself that I was lactose intolerant which drastically crippled a portion of the diet that is very much a part of my heritage. However, a year ago, a good friend of mine introduced me to a2 Milk® which I was skeptical to try at first, but when immediate effects that typically came with drinking cow’s milk never came I was amazed.
I can confidently and proudly say that this milk has changed my life. One instance being that when I discovered that I can tolerate milk again, I was overjoyed to realize that I could finally make a recipe from my childhood that I had not eaten in the longest time because one of the main ingredients is cow’s milk. It’s my favorite Peruvian dish by the name of Aji De Gallina.