The common primary symptoms of lactose intolerance are gastrointestinal include abdominal pain, diarrhea and flatulence, better known as passing gas. Less common symptoms of lactose intolerance include abdominal bloating, abdominal distention, nausea. Nausea is the sensation that there is a need to vomit. Nausea can be acute and short-lived, or it can be prolonged. When prolonged, it is a debilitating symptom.
Lactose intolerance is the inability to metabolize lactose, because of a lack of the required enzyme lactase in the digestive system. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood. People with lactose intolerance may feel uncomfortable 30 minutes to 2 hours after consuming milk and milk products. Symptoms range from mild to severe, based on the amount of lactose consumed and the amount a person can tolerate. Secondary causes show up because of the deficiency of the lactase enzyme inside the walls of small intestine.
This lack of lactase may be because of many reasons; one of the common reasons is damage of the wall by any illness. The main causes which lead to the lactose intolerance symptoms can be classified in to three categories: congenital causes, secondary causes, developmental causes. Congenital disorder or anomaly happens because of the alteration of the gene which makes lactase enzyme inside the body. The individuals of congenital disorder actually have this problem from birth.
The last and the most important cause show up due to the downfall of the lactase count inside the body. This developmental cause is also called as hypolactasia which means less lactase. Due to this cause the lactase count decreases inside the body due to the changes in the functioning of the genetic material of the individual. The occurrence of this cause varies from person to person, community to community and also ethnicity to ethnicity.
Secondary causes show up because of the deficiency of the lactase enzyme inside the walls of small intestine. This lack of lactase may be because of many reasons; one of the common reasons is damage of the wall by any illness. Due to the similarities, these three conditions can sometimes be confused.