Love Bread? It’s in Your DNA

Bread. Pasta. Cake. For many people, carbs are the ultimate comfort food. A new study published in Science helps explain why.

Humans are able to more easily utilize carbohydrates because they possess multiple copies of a gene called AMY1 (salivary amylase gene), which begins turning starch into sugar in the mouth and gives starchy foods their taste. The more copies of AMY1 a person has, the more carbs they can digest effectively.

Researchers have long known that early duplication of this gene helped shape human adaptation to starchy foods. What they didn’t know, until now, was that this duplication may have occurred more than 800,000 years ago—long before the advent of farming.

The study, co-led by University at Buffalo biologist Omer Gokcumen, used a breakthrough method of genome mapping that allowed researchers to map the AMY1 gene region in much greater detail than traditional sequencing methods could provide.

Analyzing the genomes of 68 ancient humans, including a 45,000-year-old sample from Siberia, the research team found that pre-agricultural hunter-gatherers had an average of four to eight AMY1 copies per cell, suggesting that humans were already walking around Eurasia with a wide variety of high AMY1 copy numbers well before they started domesticating plants and eating excess amounts of starch.

The study also found that AMY1 gene duplications occurred in Neanderthals. 

“The initial duplications in our genomes laid the groundwork for significant variation in the amylase region,” said Gokcumen, “allowing humans to adapt to shifting diets as starch consumption rose dramatically with the advent of new technologies and lifestyles.”

In other words, the initial duplication was like the first ripple in a pond, creating a genetic opportunity that later shaped our species. As humans spread across different environments, the flexibility in the number of AMY1 copies provided an advantage for adapting to new diets, particularly those rich in starch.

The research also highlights how agriculture impacted AMY1 variation. While early hunter-gatherers already had multiple gene copies, European farmers saw a surge in the average number of AMY1 copies over the past 4,000 years, likely due to their starch-rich diets.

“Individuals with higher AMY1 copy numbers were likely digesting starch more efficiently and having more offspring,” explained Gokcumen. “Their lineages ultimately fared better over a long evolutionary timeframe than those with lower copy numbers, propagating the number of the AMY1 copies.”

According to the research team, further exploration of this genetic variation could shed light on the processes behind starch digestion and glucose metabolism, ultimately deepening our understanding of genetics, nutrition and health.