乳糖(主要含于牛奶中)随牛奶摄入后,必须经小肠粘膜中的乳糖酶水解成葡萄糖与半乳糖后,才能被吸收利用。如果小肠中乳糖酶不足或缺乏时,未被充分水解的乳糖进入结肠后,经细菌发酵而产酸产气(主要是氢气)刺激肠道,以致饮奶后产生嗳气、腹胀、腹痛与腹泻等症状,这就是部分人不宜饮用牛奶的重要原因。另有部分人饮奶后虽不产生上述症状,但仍可发生乳糖吸收不良,最后可导致 Lactose (mainly contained in milk) with milk intake, must be in the intestinal mucosa of lactase hydrolysis of glucose and galactose before they can be absorbed. If the lactase in the small intestine is deficient or absent, the lactose that has not been sufficiently hydrolyzed enters the colon and is fermented by the bacteria to produce acid gas (mainly hydrogen) to stimulate the intestine, resulting in asthma, bloating, abdominal pain and diarrhea, etc. after lactation Symptoms, which is why some people should not drink milk an important reason. While some people drink milk after the above symptoms, but can still occur lactose malabsorption, which can eventually lead to