乳糖酶缺乏是一个世界性的问题，体内乳糖酶水平一般随年龄增长而降低或消失，其发生率随种族和地区而异。如欧洲白种人为５％～３０％，亚洲黄种人为７６％～１００％，非洲黑人为９５％～１００％，世界上乳糖酶缺乏的发生率平均为７５％左右。我们以前的研究证明中国７～１ Lactase deficiency is a worldwide problem, the body lactase levels generally lower or disappear with age, the incidence varies with race and region. For example, European white people are 5% to 30%, Asian Yellow people is 76% to 100%, African blacks are 95% to 100%, and the incidence of lactase deficiency in the world is about 75% on average. Our previous research shows that China 7 ~ 1