If you are Asian, there’s a very high chance you are one of the millions of people who experience lactose intolerance.
Lactose intolerance is a condition where the human body stops producing enough lactase, the essential enzyme needed to break down milk sugar. Because of this, consuming dairy products like a simple glass of fresh milk can trigger uncomfortable symptoms.
In mild cases, it causes stomach pain and bloating. However, when it’s severe, lactose intolerance can lead to dizziness, vomiting, or even diarrhea.
Far from being a disease, this is actually a completely normal biological trait for adults in this region. In fact, research shows that 90 to 100 percent of adults in East and Southeast Asia are lactose intolerant.
Across Southeast Asia, the number of people who cannot digest lactose is incredibly high, reaching 85 to 98 percent.
So, why is this trait so incredibly common among Asians?
Genetic Factors and Evolution
Prof Ronny Rachman Noor, an Ecological Genetics Expert at IPB University, explained that Asians generally do not have the “lactase persistence” gene mutation for adulthood. This mutation appeared about 7,500 years ago in Northern Europe where cattle farming was very common.
Moreover, according to Frontiers in Nutrition written by Jiao HT et al., most Asians carry the C/C genotype. This trait means that the body's ability to digest lactose naturally declines after a child is finished with breastfeeding.
In contrast, many people with Northern European ancestors have a mutation that keeps their lactase levels high forever. This explains why a person from Sweden drinks milk easily while someone from Vietnam feels sick.
This unique phenomenon this is called "gene-culture co-evolution" because habits changed our DNA. When humans started raising cows, their bodies adapted over generations to this new food source.
The ability to digest milk as an adult is actually a very unusual trait in the long history of all mammals. Most animals and humans are naturally designed to stop drinking milk once they are no longer young babies.
History and Solutions
Geography also played a massive role in why various Asian populations did not develop the ability to process fresh dairy products. In warmer climates like Southeast Asia, it was historically very difficult to keep fresh cow's milk from spoiling in the tropical heat.
Hot weather and tropical diseases made raising large herds of dairy cattle much harder than in the cold northern regions of the world. Because of these environmental challenges, milk was not a regular or traditional part of the diet for many centuries in these areas.
The "calcium assimilation hypothesis" suggests that people in cold, dark regions specifically needed milk to get enough Vitamin D and calcium. Since people in Asia usually get plenty of sunlight, their bodies did not have the same biological pressure to adapt to drinking milk.
So, what to consume instead?
Many Asian cultures have traditionally used fermented products like yogurt or hard cheeses to avoid experiencing any digestive problems or pain. These specific foods have much less lactose because the fermentation process naturally breaks down the milk sugar for the human body.
Lactose-free milk and special enzyme supplements are also great modern options for those who still want to enjoy dairy products. These products provide all the nutritional benefits of milk without the uncomfortable stomach pain that usually follows for many people in Asia.
Individuals can also get their daily calcium from many plant-based sources like tofu, tempeh, and various types of nutritious legumes. These foods are already a staple in many Asian kitchens and are excellent for maintaining a healthy and strong body.
