✪ Key Takeaway: Lactose intolerance affects 75 percent of adults worldwide because losing the ability to digest milk after weaning is normal.
Introduction
You drink a glass of milk and thirty minutes later your stomach starts making strange noises.
You feel bloated, uncomfortable, and wonder if something is wrong with your body when the truth is that your body is doing exactly what nature intended for most adult humans.
Hi, I am Abdur, your nutrition coach and today I am going to explain why lactose intolerance affects three out of every four adults worldwide and why this is completely normal from an evolutionary perspective.
Why Do Most Adults Lose The Ability To Digest Milk?
Every mammal on Earth produces milk specifically for feeding their young during infancy.
Human babies are born with high levels of an enzyme called lactase in their small intestine which breaks down lactose, the sugar found in milk.
After weaning, which typically happens between ages two and five, the body naturally reduces lactase production because milk is no longer needed for survival.
This process is called lactase non-persistence and it represents the normal genetic state for humans throughout most of our evolutionary history.
When lactase levels drop, undigested lactose moves into the colon where bacteria ferment it, causing gas, bloating, diarrhea, and abdominal discomfort within 30 minutes to two hours after consuming dairy products.
✪ Fact: Humans are the only species that regularly consumes milk from other animals after weaning, which is why lactose intolerance is so common.
Which Populations Can Digest Milk And Why?
About 25 percent of adults worldwide maintain the ability to digest lactose throughout their lives due to a genetic mutation called lactase persistence.
This mutation developed independently in several populations that historically relied on dairy farming for survival, including Northern Europeans, some African groups, and Middle Eastern populations.
In these communities, being able to digest milk as an adult provided a significant survival advantage during times when other food sources were scarce.
Northern Europeans show the highest rates of lactase persistence, with up to 90 percent of adults able to digest dairy products without problems.
Meanwhile, East Asian, West African, Arab, Jewish, Greek, and Italian populations show lactose intolerance rates ranging from 60 to 100 percent because dairy farming was not historically central to their diets.
✪ Note: Your ability to digest milk as an adult depends on your genetic ancestry, not your current diet or lifestyle choices.
How Does Lactose Intolerance Differ From Milk Allergy?
Many people confuse lactose intolerance with milk allergy, but these are completely different conditions with different causes and symptoms.
Lactose intolerance is a digestive issue caused by insufficient lactase enzyme production, resulting in uncomfortable but not dangerous symptoms like bloating, gas, and diarrhea.
Milk allergy is an immune system response to proteins in milk, primarily casein and whey, which can cause serious reactions including hives, wheezing, vomiting, and in severe cases, anaphylaxis.
Milk allergy typically affects 2 to 3 percent of infants and young children, with most outgrowing it by age five, while lactose intolerance usually develops during adolescence or adulthood.
People with lactose intolerance can often tolerate small amounts of dairy or fermented products like yogurt and cheese, while those with milk allergy must avoid all dairy products completely.
✪ Pro Tip: If you experience digestive symptoms after dairy, try eliminating it for two weeks and then reintroduce it to confirm lactose intolerance rather than allergy.
Can You Still Get Nutrients Without Drinking Milk?
The dairy industry has successfully convinced many people that milk is essential for strong bones and good health, but this is misleading marketing rather than scientific fact.
Countries with the highest dairy consumption, including the United States, Sweden, and Finland, actually have some of the highest rates of osteoporosis and hip fractures in the world.
Meanwhile, populations in Asia and Africa who consume little to no dairy throughout their lives maintain strong bones through other calcium sources like leafy greens, legumes, nuts, seeds, and fortified foods.
You can easily meet your daily calcium needs through foods like kale, broccoli, bok choy, almonds, tahini, white beans, sardines with bones, and fortified plant milks without ever touching dairy products.
The key to bone health is not dairy consumption but rather adequate vitamin D, regular weight-bearing exercise, sufficient protein intake, and avoiding excessive sodium and caffeine that can increase calcium loss.
✪ Fact: One cup of cooked collard greens provides more absorbable calcium than one cup of milk because plant calcium has higher bioavailability.
What Should You Do If You Have Lactose Intolerance?
If you experience digestive discomfort after consuming dairy, the first step is recognizing that your body is functioning normally according to human evolutionary biology.
You can choose to completely avoid dairy products, which is the simplest and most effective approach for managing symptoms while ensuring you get nutrients from other sources.
Alternatively, you can experiment with fermented dairy products like yogurt, kefir, and aged cheeses which contain lower lactose levels and beneficial bacteria that help with digestion.
Some people find success using lactase enzyme supplements before consuming dairy, though this approach treats the symptom rather than addressing the underlying biological reality that your body no longer needs milk.
The most important thing is listening to your body and making choices based on how you feel rather than following outdated nutritional guidelines that assume everyone should consume dairy products daily.
✪ Pro Tip: Start a food diary tracking dairy intake and symptoms for two weeks to identify your personal tolerance level and which products cause problems.
The Bottom Line
Lactose intolerance is not a disease or disorder but rather the normal biological state for the majority of adult humans across the planet.
Your body rejecting milk after childhood is not a failure but a reminder that nature designed us to move beyond infant nutrition as we mature and develop.
I would love to hear your experience with dairy products and whether you have found alternatives that work better for your body, so please share your thoughts in the comment section below.
References
At NutritionCrown, we use quality and credible sources to ensure our content is accurate and trustworthy. Below are the sources referenced in writing this article:
- World Population Review: Lactose Intolerance by Country 2024
- National Center for Biotechnology Information: Lactose Intolerance – StatPearls
- MedlinePlus: Lactose Intolerance: MedlinePlus Genetics
- Science Learn: Genes and Lactose Intolerance
- Nahrungsmittel Intoleranz: Lactose Intolerance: Worldwide Distribution
