Dairy products are one of the most common causes of allergies because they were introduced late to the human diet. We haven't adapted well to dairy, and a lot of people have bad reactions to it - even more so among black people, some of whom don't tolerate dairy well. I think that's because in their heritage, it was introduced even later than in European culture.

My husband and I make kefir from soya, which is like a plain yogurt, with lots of health benefits.