Lactose intolerance is the inability to fully digest lactose, the natural sugar found in milk and dairy products, caused by insufficient production of lactase, the enzyme responsible for breaking lactose down in the small intestine.

When undigested lactose passes into the colon, it's fermented by gut bacteria, producing gas and drawing in water, which typically causes symptoms like bloating, cramping, and diarrhea within a few hours of consuming dairy.

A Missing Enzyme, Not an Allergy

Why It's So Common Globally

It's important not to confuse lactose intolerance with a milk allergy β€” intolerance is a digestive issue involving an enzyme deficiency, while a true milk allergy involves the immune system reacting to milk proteins and can be considerably more serious.

Lactase production naturally declines with age in most of the world's population after infancy, which is why lactose intolerance is actually the more common global condition, while the ability to digest dairy easily into adulthood is a genetic trait more concentrated in certain populations with long histories of dairy farming.

Sources

  1. Wikipedia β€” overview of lactose intolerance and its global prevalence
  2. National Institute of Diabetes and Digestive and Kidney Diseases β€” clinical background on lactose intolerance
  3. Mayo Clinic β€” patient-facing overview of lactose intolerance symptoms and management

FAQ

Is lactose intolerance the same as a milk allergy?

No β€” lactose intolerance is a digestive issue involving an enzyme deficiency, while a milk allergy involves the immune system reacting to milk proteins and can be more serious.

Why does lactose intolerance become more common with age?

Lactase production naturally declines with age in most of the world's population after infancy, reducing the body's ability to digest lactose over time.

Is lactose intolerance actually the global norm rather than the exception?

In terms of prevalence, yes β€” the ability to easily digest dairy into adulthood is a genetic trait more concentrated in certain populations, rather than the global default.

About the Author

We reference Wikipedia, National Institute of Diabetes and Digestive and Kidney Diseases, and Mayo Clinic to explain the background and current understanding of this topic.

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