For ages, humans have had a palpable love for foods rich in carbohydrates, from pasta to bread. This craving isn’t just modern culinary preference; it appears to be deeply rooted in our evolutionary history. Recent research indicates our ability to efficiently digest starch may date back hundreds of thousands of years, shaping our diets long before agriculture was ever practiced.
A groundbreaking study published on October 17, 2024, reveals fascinating insights about the genetic adaptations related to starch digestion. The study—conducted by researchers from the University at Buffalo and The Jackson Laboratory—focuses on the salivary amylase gene, known as AMY1, which produces the enzyme amylase. This enzyme is what allows our bodies to break down starchy foods like potatoes, rice, and bread.
Previously, it was assumed our ancestors primarily consumed proteins as part of their diet, with the prevailing stereotype portraying ancient humans as meat-heavy eaters. But new archaeological evidence suggests otherwise—our ancestors likely roasted tubers and consumed other starchy foods, hinting at a more balanced diet than previously thought. Consequently, the evolution of AMY1 has provided fans of bread and pasta with more evidence of how carbohydrates have been important over thousands of years.
At the heart of these findings lies the AMY1 gene. While humans can have varying numbers of AMY1 copies—ranging from one to over eleven—the researchers discovered interesting data by analyzing the ancient genomes of 68 people, including one individual from Siberia who lived about 45,000 years ago. They found these ancient hunter-gatherers already had between four to eight copies of the AMY1 gene. This suggests they were genetically geared for starch digestion long before the introduction of agriculture.
Why did this adaptation occur? According to Omer Gokcumen, the lead author and a geneticist at the University at Buffalo, the increase in AMY1 copies can be traced back to when humans started to evolve their diets through cooking. Cooking with fire made starch-rich foods more digestible, which would have added to the natural selection process favoring those who produced higher amounts of amylase.
Digging even farther back, the study postulates the first duplications of the AMY1 gene occurred more than 800,000 years ago. Researchers also found similar AMY1 duplications within Neanderthals and Denisovans, indicating the roots of starch digestion lie even closer to our common ancestors.
These adaptations provided some significant evolutionary advantages. Those early humans who possessed more copies of AMY1 likely digested starch more efficiently, which could have made them more successful at reproducing compared to those with fewer copies. Gokcumen emphasizes this by stating, “Individuals with higher AMY1 copy numbers were likely digesting starch more efficiently and having more offspring.”
This evolutionary advantage became even more pronounced with the agricultural revolution around 12,000 years ago. Populations began domestic farming, which included the cultivation of wheat, barley, and other starch-rich plants. Genetic samples from skeletons dating back to this period confirmed the increasing prevalence of AMY1 gene copies, which showcased how natural selection sharply increased their survival chances.
Interestingly, as humans migrated and diversified, the number of AMY1 gene copies adjusted according to local dietary necessities. For example, those who relied more heavily on starch storage were favorable for fostering their own genetic lines. This genetic flexibility allowed humanity to adapt seamlessly to diverse environments across the globe.
Today, our fascination with carbohydrates remains, but it also has health ramifications. Issues like obesity and type 2 diabetes have become more common due to high starch and carbohydrate diets. The variation of the AMY1 gene could present valuable insights concerning metabolic health and nutrition, and researchers like Feyza Yilmaz from JAX have pointed out how unraveling this gene's tales might lead to medical treatments aimed at combating such modern dietary issues.
“Given the key role of AMY1 copy number variation in human evolution, this genetic variation presents exciting opportunities to explore its impact on metabolic health,” Yilmaz noted. She emphasized the importance of continuing research to reveal how variations of AMY1 could affect individuals living with modern-day dietary challenges.
Scientists agree we are now at the cusp of breakthroughs concerning how our body functions relative to the foods we eat, unlocking evolutionary lessons about our diets which could redefine nutritional science moving forward.
These discoveries give us not only more perspective on our love for carbs but also highlight the complex relationship between evolution, diet, and health. The findings spur curiosity about the potential medical advancements tied to our ancient ancestry and genetic make-up, which might one day provide answers for the dietary concerns plaguing modern society.
The research does more than just discuss the distant past, it hints toward the future of nutritional and health science, potentially transforming the way we approach weight loss and healthy eating.
