Why Do People Become Lactose Intolerant?

How did people become lactose intolerance? How is still prevalent amongst people? These are just some of the questions that I have asked myself and I am sure others have wondered about as well. When my doctor first told me I was lactose intolerant, he explained to me as to why. 

My doctor explained to me that African Americans, Latinos, Native Americans, and other indigenous people have higher chances of being lactose intolerant. He went on to talking about how the start of lactose intolerance dates back to the 15th century. Cows originate from Europe. They were first introduced to Native Americans and African Americans in the “New World.” When the cow’s milk was introduced to the indigenous and African Americans, they most likely experienced cramps, bloating, gas and diarrhea. Why? Because their bodies did not produce the lactase enzyme in order to properly digest the sugars in milk. They bodies were not familiar with diary.

Overtime, people started  to gain a tolerance for dairy. However, the intolerance to digest lactose still prevails in these ethnicities leading to lactose intolerance being genetic. This is known as primary hypolactasia.  Although it can be genetic, lactose intolerance– as mentioned in one my previous posts– can also develop overtime due to the lack of the lactose enzyme production in your small intestine, which is known as secondary hypolactasia. Some people can also be born with lactose intolerance, which is known as congenital lactase deficiency, but it is not very common.