The wisdom of the Donguibogam remains relevant today because it aligns closely with modern science. Lactose intolerance, where drinking milk triggers abdominal pain and diarrhea, provides a clear modern medical explanation for what Korean medicine describes as hypofunction of the spleen and stomach and excess dampness.
The process of digesting milk is complex. Milk contains a sugar called lactose, which requires a digestive enzyme called lactase to be broken down properly. Lactase is secreted by the small intestinal mucosa, functioning like a key that breaks lactose down into smaller units of glucose and galactose so the body can absorb them. However, individuals with lactose intolerance lack sufficient lactase or have reduced enzyme activity.
When lactase is deficient, lactose cannot be properly absorbed in the small intestine and passes directly into the large intestine. Once there, bacteria ferment the lactose, producing substantial amounts of gas, fatty acids, and lactic acid. This gas causes abdominal distension, rumbling noises, and flatulence. Furthermore, the byproducts of fermentation and the undigested lactose raise the osmotic pressure inside the large intestine. This draws surrounding water into the colon and increases the moisture content of the stool, directly causing diarrhea.
Lactose intolerance is broadly divided into two types. The first is primary lactose intolerance, which affects more than 70 percent of the world adult population. In this genetically programmed type, individuals digest breast milk or dairy well during childhood, but lactase secretion naturally declines with age. It is known to be particularly prevalent among East Asians, including Koreans. The second is secondary lactose intolerance, where lactase production temporarily drops due to conditions causing inflammation or damage to the small intestine, such as enteritis, Crohn's disease, or celiac disease. Once the intestinal lining recovers, the ability to digest milk may return.
Lactose intolerance is not merely an upset stomach, but a distinct physiological response involving the digestive enzyme system and the gut microbiome. Paying attention to how your body responds to dairy can help you manage your digestive comfort effectively.
