When I was younger I never heard of lactose intolerance. In recent years it has become almost common place. Grocery store aisles contain dozens of “safe” dairy products and aids for digesting natural dairy foods. The condition is so well known that it’s become a comedic tool in popular TV programs. Leonard Hofstadter’s lactose intolerance pops up at just the right moments in many episodes of The Big Bang Theory.
For sufferers, and in many cases their loved ones, lactose intolerance is no laughing matter. Within several hours of dairy consumption cramps, bloating, nausea, flatulence, and diarrhea visit the poor sufferer. These symptoms are not caused by an allergy to milk. Rather a decreased ability to digest lactose, a sugar found in milk, causes them.
Digesting lactose in the small intestine requires the enzyme lactase. Insufficient production of lactase allows lactose to reach the colon. Microorganisms in the colon process the lactose through fermentation. By-products of the fermentation include the gases hydrogen, carbon dioxide, and methane. The abundance of these gases and other aspects of the process create the unpleasant symptoms.
Causes
With the exception of some premature babies or a genetic disorder everyone is born with the ability to digest lactose. However the majority of people lose that ability as they reach adulthood. While some lose it because of digestive disorders like celiac disease most lose it naturally. This is a trait humans share with most mammals except for those of us who have a specific genetic mutation. The mutation known as lactase persistence disables the DNA that turns off lactase production.
The mutation is relatively new. Through genetic analysis of ancient skeletons we know it appeared in Europe a little more than 4,000 years ago. While the benefits of persistence moved through Europeans, the mutation hasn’t reached other populations. Approximately 90% of northern Europeans are lactase persistent, while the opposite is true for east Asians and most Africans.
I guess this explains why European dishes often include cheese or dairy while Asian foods don’t.
As always thanks for reading.
Armen
Note to Pay the Bills: None of the books in the Misaligned Series features a lactose intolerant character, but they do have other elements in common with The Big Bang Theory. Like the popular TV show, the series includes elements of theoretical physics. How does theoretical physics fit into a Young Adult fantasy series about Welsh mythology? Learn more by reading a summary of the series here or find links to purchase books here.
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