BIG Nutrition: Is a protein the cause of intolerance to cow’s milk?


BIG Nutrition: Is a protein the cause of intolerance to cow’s milk?

Ever drink milk and think, “It just doesn’t seem to agree with me anymore.” Perhaps you thought, or someone suggested, that you might be lactose intolerant. That is certainly possible, but it may also be an intolerance to one the proteins that is commonly found in cow’s milk.

Emerging research suggests that some individuals may have difficulty digesting a protein (A1 beta-casein) that can be in milk. A new type of milk, called A2 milk, has milk from cows that only produce A2 beta-casein protein.

Why not just stop consuming cow’s milk altogether? Certainly one could do that, but it is tough to find a food or beverage that is packed with as many nutrients as milk. It contains a significant amount of protein (8 grams/cup in the form of whey and casein) and carbohydrate, is fortified with Vitamins D and A, and contains minerals (eg, calcium, magnesium, and potassium) that are helpful for athletes.

Overall, further research is needed to understand whether proteins in the milk may be contributing to digestive issues for some people. For an individual, sorting out whether the concern is lactose or protein intolerance can be a bit of a trial, but it is possible. Low lactose options are yogurt and hard cheese; lactose-free milks are also available. A2 milk was recently made available in the US and is at Wegmans and Stop and Shop. It is free of the A1 beta-casein protein but contains lactose; the same is true for goat and sheep milk. Because lactose and milk proteins can be ingredients in foods, knowledge about food ingredients is helpful to sort out protein or lactose intolerance or find alternatives. Feel free to contact me if you are interested in milk or milk products, but finding them difficult to include in your eating plan.

Happy and healthful eating,

Donna G. Pertel, MEd, RD, LDN


Interested in sorting out troubles with milk? Contact me at [email protected]