What does lactose intolerance mean?

Generally, lactose intolerance refers to a condition in which the human body is unable to completely digest lactose in dairy products due to a deficiency of lactase or reduced lactase activity, leading to a series of discomfort symptoms after lactose ingestion. A detailed explanation is as follows:

Lactose is a disaccharide present in milk and other dairy products, which must be broken down into glucose and galactose by lactase before it can be absorbed by the human body. When the body lacks lactase or has insufficient lactase activity, lactose cannot be adequately digested and absorbed in the small intestine. Undigested lactose enters the large intestine, where it is fermented by intestinal bacteria, producing large amounts of gas such as hydrogen and carbon dioxide. This process also increases the osmotic pressure within the intestine, leading to increased water content in the gut, which can cause symptoms such as bloating, diarrhea, and abdominal pain. Additionally, factors such as an individual's intestinal microbiota composition, gastrointestinal health, and genetic factors may also influence the occurrence and severity of lactose intolerance. For example, an imbalance in the intestinal microbiota may further exacerbate difficulties in lactose digestion and absorption.

In daily life, low-lactose or lactose-free milk and dairy products such as yogurt can be selected. These products have been specially processed to remove or reduce lactose content, thereby decreasing gastrointestinal irritation and reducing the risk of discomfort while still meeting nutritional needs.