If having a little milk with your cookies doesn’t make you smile, you might be experiencing lactose intolerance.
Symptoms like bloating, indigestion or nausea after drinking a glass of milk or eating cheese are surprisingly common.
So, what exactly is lactose intolerance, how does it develop, and does it have a genetic component?
What is Lactose Tolerance Mutation?
Lactose intolerance is simply the body’s reduced ability to digest lactose, the sugar found in milk. When babies are born, their primary food source is milk. A baby’s body uses the enzyme lactase phlorizin hydrolase to digest that milk. (An enzyme is a chemical substance found in the human body that helps natural processes such as digestion go smoothly.) This particular enzyme is used to break apart the lactose sugar into glucose and galactose, which are later used to create the usable energy the body needs.
As babies grow and are weaned off milk, they begin eating other foods and the enzyme activity reduces as the need for milk decreases. Because the enzyme activity lessens, individuals sometimes have a reduced ability to break down the sugar in milk and dairy products properly. This causes bloating, nausea, abdominal pain, and diarrhea after the consumption of dairy products.
How does our DNA determine lactose tolerance or intolerance
Our ability to process nutrients, and how effectively we process them, is controlled by our genes. The ability to process dairy products is one of the best examples of evolutionary necessity and advantage in the study of nutrigenetics. Some people can consume seemingly unlimited amounts of milk and ice cream with no trouble, while others will spend a few hours in extreme discomfort from a tablespoon of sour cream. Why is that?
What causes lactose intolerance?
It might surprise you to find out that the ability to digest dairy past infancy is a relatively new development in human evolution. This was a change that occurred when we transitioned from nomadic to sedentary lifestyles. The domestication of cows and other dairy-producing animals allowed humans to continue drinking milk after weaning from breastmilk. The earliest records of cattle domestication indicate that Middle Eastern and North African populations were among the first to do so between 7500-9000 years ago.
The vast majority of newborns are lactose tolerant so they can digest breast milk. After weaning, the gene that encourages production of lactase in the digestive tract basically deactivates (turns off) when the child no longer consumes dairy. In modern times, with milk so readily available and heavily encouraged as part of a healthy diet, lactase production continues as an evolutionary advantage.
For lactose intolerant individuals that just can’t get away from dairy products, there are a few over-the-counter and prescription supplements that can be taken before a meal to aid digestion and prevent uncomfortable symptoms.
How common is lactose intolerance today?
Some estimates place true lactose intolerance as high as 10% in the U.S. population. However, this is certainly not the case in other countries or cultures. In Asian cultures, for example, up to 99% of the population lacks the gene mutation for lactose tolerance. Milk is not part of their traditional diet, so there was no evolutionary need to develop a tolerance to dairy in their populations.
It is important to note that there are rare instances of babies born with a mutation in the LCT (lactase-glycosylceramidase) gene, resulting in a condition called congenital lactase deficiency, or congenital alactasia. Infants with this mutation are unable to consume and digest even their own mother’s breast milk without GI symptoms. Fortunately, several lactose-free options are now available in most of the developed world to ensure these babies are comfortable and well-nourished.
Alternatives to Dairy Milk
- Almond Milk
- Cashew Milk
- Coconut Milk
- Soy Milk
- Rice Milk
- Hemp Milk
- Lactose-Free Milk
There are a number of delicious and healthy ways to swap out lactose in your diet and still enjoy your favorite foods requiring milk and cheese. Just peruse the cold cases are your grocery store to see myriad alternatives. Don’t forget to check out the vegan area of the cheese and yogurt areas to find non-dairy options, as well!