The phrase 'Which race do they drink milk after?' holds a literal and a deeper, more scientific interpretation. The first points directly to a storied sporting tradition, while the second reveals a story of human evolution and dietary adaptation. Both topics illuminate the surprising contexts surrounding milk consumption.
The Indianapolis 500 Victory Tradition
For nearly a century, the victor of the Indianapolis 500 motor race has celebrated by drinking a bottle of milk in Victory Circle. This iconic tradition began in 1936 when driver Louis Meyer, a three-time winner, asked for a glass of buttermilk to quench his thirst after the grueling race. A photograph of him doing so was captured by a newsreel cameraman, and a dairy industry executive saw the marketing opportunity. The tradition was institutionalized in 1956, and today, each competing driver submits their milk preference—fat-free, 2%, or whole milk—before the race. This ceremonial act is one of the most beloved and recognizable traditions in motorsports.
Decoding the Genetic Adaptation for Milk Digestion
Beyond the racetrack, the ability to consume milk without discomfort is determined by genetics, not 'race' in the modern sense. The term 'race' is an outdated and scientifically inaccurate way to categorize human populations, especially concerning complex genetic traits. A more accurate lens is to examine lactase persistence, the trait that allows adults to continue producing the enzyme lactase, which digests the milk sugar lactose. Most human adults, like all other mammals, naturally stop producing significant amounts of lactase after infancy. This is the ancestral condition for humans.
Lactase persistence, however, has evolved independently in several human populations that developed pastoralist, or herding, cultures. This is a prime example of gene-culture co-evolution, where a cultural practice—dairying—created a strong selective advantage for a particular genetic trait.
Where Lactase Persistence is High
Genetic studies show a high frequency of lactase persistence in certain populations, including:
- Northern Europeans: With rates as high as 89–96% in some regions like the British Isles and Scandinavia, this population has some of the highest lactase persistence frequencies globally.
- Specific African Pastoralist Groups: Some traditionally herding groups in Africa, such as the Maasai and Fulani, also have high rates of lactase persistence, though caused by different genetic mutations than in Europeans.
- Middle Eastern and Central Asian Populations: Some populations in these regions also exhibit moderate to high rates of lactase persistence, often linked to a history of pastoralism involving cattle, goats, or camels.
Where Lactase Non-Persistence is Common
The majority of the world's population remains lactase non-persistent. This is particularly prevalent in:
- East Asians: With rates of lactose intolerance between 70–100%, many East Asian communities historically did not rely on dairy from domesticated animals.
- West Africans: In West Africa, lactose intolerance is widespread, affecting approximately 80% of the adult population.
- Indigenous Americans and Oceania: These populations also show low rates of lactase persistence, reflecting traditional diets that did not include dairy from domesticated animals.
The Evolutionary Drivers of Lactase Persistence
While dairying created the initial selective pressure, recent research suggests additional factors may have turbocharged the evolution of lactase persistence. A 2022 study combined archaeological, genetic, and environmental data to build a new model. It revealed that milk use was widespread for thousands of years in Europe before the lactase persistence gene became common. The rapid increase of the trait was instead correlated with periods of famine and pathogen exposure. In times of hardship, drinking unfermented milk, which contains high levels of lactose, would have caused severe, and potentially fatal, diarrhea in lactose-intolerant individuals who were already malnourished. In contrast, those with lactase persistence would have had a critical survival advantage. The same advantage would apply in environments with poor sanitation and high pathogen loads.
Genetic Variants and Health Implications
The ability to digest milk is linked to different genetic mutations depending on the population. The European variant, T-13910, is the most common among people of European descent. However, several other variants exist in African populations, highlighting the convergent evolution of this trait. Beyond digestion, ongoing research using Mendelian randomization is exploring potential health effects associated with milk consumption, with findings suggesting links to conditions like cataracts, hyperlipidemia, and, positively or negatively, body mass index, depending on the specific study.
Comparison of Lactase Digestion Across Populations
| Population Group | Typical Lactase Persistence Rate | Primary Evolutionary Driver | Example |
|---|---|---|---|
| Northern Europeans | Very high (>80%) | Dairy farming, with selection intensified by famine and disease. | Scandinavian, British |
| East African Pastoralists | High (~50-90%) | Pastoralist culture and reliance on milk in arid climates. | Maasai, Fulani |
| East/Southeast Asians | Very low (<10%) | No historical tradition of widespread dairying. | Chinese, Japanese, Korean |
| West Africans | Low (<20%) | Less reliance on dairying, different historical subsistence patterns. | Various agriculturalist groups |
| Southern Europeans | Moderate (50-60%) | Dairying, but different historical selective pressures. | Italian, Greek |
| Indigenous Americans | Very low (<5%) | No dairying cultures prior to European contact. | Various tribes |
Conclusion: A Tale of Two Realities
Ultimately, the phrase 'Which race do they drink milk after?' can be understood on two entirely different levels. It can refer to the winner's milk tradition at the Indianapolis 500, a cherished sporting ritual steeped in a specific history. Simultaneously, it touches upon the complex genetic and evolutionary history of lactase persistence, a trait that developed independently in different human populations. The science shows that our ability to enjoy milk as adults is a matter of genetic adaptation shaped by cultural practices and environmental pressures, demonstrating how deeply biology and culture are intertwined.
For more detailed scientific information on the evolution of lactase persistence, visit the National Institutes of Health (NIH) resource on the subject.
