45+ Symptoms Of Lactose Intolerance In Adults Mayo Clinic Pics. Lactose intolerance is the inability to digest lactose, the sugar in milk and dairy products. When the body is unable to break.

Lactose intolerance happens when a person has too little lactase.

Primary lactose intolerance (or congenital lactose intolerance) is a very rare genetic condition. Lactose intolerance is caused by lactose lactase levels get lower with age. The prevalence of lactose intolerance in adults varies from less than 5 percent to almost 100 percent among different populations, according to research according to the mayo clinic, most people with lactase deficiencies do not display any signs or symptoms. Lactose intolerance is when your body can't break down or digest lactose.