de Vrese M, Sieber R, Stransky M
Institut für Physiologie und Biochemie der Ernährung, Bundesanstalt für Milchforschung, Kiel.
Schweiz Med Wochenschr. 1998 Sep 19;128(38):1393-400.
The disaccharide lactose is naturally present as a component of foods in milk and dairy products. In the gastrointestinal tract, lactose is hydrolysed by the enzyme beta-galactosidase (lactase) into glucose and galactose. These components are absorbed. In most people lactase activity decreases at the age of approximately 2 years of age. After this lactose intake can cause symptoms of bloating, flatulence, abdominal pain and diarrhoea due to the lactose reaching the large intestine. This phenomenon is called lactose intolerance. It is generally recommended that these people abandon the consumption of milk and dairy products. However, most lactose-intolerant people are able to digest small amounts of milk (approximately 200 ml). They can also consume cheese without (hard and semi-hard cheese) or only low lactose content (only present in 10% of soft cheese). These products are a very important source of calcium.
双糖乳糖天然存在于牛奶和奶制品等食物中。在胃肠道中，乳糖被β-半乳糖苷酶（乳糖酶）水解成葡萄糖和半乳糖。这些成分会被吸收。在大多数人身上，乳糖酶活性在大约2岁时会下降。此后，由于乳糖进入大肠，摄入乳糖会导致腹胀、肠胃胀气、腹痛和腹泻等症状。这种现象被称为乳糖不耐受。一般建议这些人放弃食用牛奶和奶制品。然而，大多数乳糖不耐受的人能够消化少量牛奶（约200毫升）。他们也可以食用不含乳糖（硬奶酪和半硬奶酪）或乳糖含量低的奶酪（仅10%的软奶酪含有乳糖）。这些产品是非常重要的钙源。
