With sugar malabsorption, intestinal mucosal enzymes, such as lactase, which splits lactose to galactose and glucose, may be congenitally absent or temporarily deficient secondary to GI infection.

• 糖吸收不良：小肠粘膜酶，如乳糖酶能将乳糖分解成半乳糖和葡萄糖，可能是先天缺失或因胃肠感染引起暂时不足。