Lactose intolerance is very common.
In fact, it’s thought to affect around 75% of the world’s population.
People with lactose intolerance experience digestive problems when they eat dairy, which can have a negative effect on quality of life.
Lactose intolerance is an impaired ability to digest lactose, a sugar found in milk and other dairy products. Lactose is normally broken down by an enzyme called lactase, which is produced by cells in the lining of the small intestine.
Congenital lactase deficiency, also called congenital alactasia, is a disorder in which infants are unable to break down lactose in breast milk or formula. This form of lactose intolerance results in severe diarrhoea. If affected infants are not given a lactose-free infant formula, they may develop severe dehydration and weight loss, however, it’s a rare condition.
Lactose intolerance in adulthood is caused by reduced production of lactase after infancy (lactase non-persistence). If individuals with lactose intolerance consume lactose-containing dairy products, they may experience abdominal pain, bloating, flatulence, nausea, and diarrhea beginning 30 minutes to 2 hours later.
Most people with lactose intolerance retain some lactase activity and can include varying amounts of lactose in their diets without experiencing symptoms. Often, affected individuals have difficulty digesting fresh milk but can eat certain dairy products such as cheese or yogurt without discomfort. These foods are made using fermentation processes that break down much of the lactose in milk.