Secret of why we love to eat bread and pasta is revealed in our ancient roots

Research has revealed that humans may have developed the ability to start digesting carbohydrates in the mouth long before they started farming, and maybe even before the split from Neanderthals

Your love for carbs like bread and pasta might be due to ancient DNA, according to new research.

The study suggests that humans may have developed the ability to start digesting these foods in the mouth long before they started farming, possibly even before the split from Neanderthals. The research discovered that the gene for starch-digesting saliva may have first duplicated over 800,000 years ago, paving the way for the genetic change that influences our diets today.

Duplication is a type of mutation that results in one or more copies of a gene. Experts have known for some time that humans carry multiple copies of a gene that allows the starch in complex carbohydrates – including foods like potatoes, rice and certain fruits and vegetables – to start breaking down in the mouth.

This is the initial step in digesting these foods, and the more copies of these genes people have, the better they are at breaking down carbohydrates. However, it's been challenging for researchers to determine when and how the number of these genes increased.

A new study led by the University of Buffalo (UB) and the Jackson Laboratory (JAX) in the US found that the duplication of the gene – known as the salivary amylase gene (AMY1) – may not only have helped shape human adaptation to starchy foods, but may have occurred as far back as over 800,000 years ago, long before the advent of farming.

Scientists have revealed that the enzyme amylase isn't only pivotal in converting starch into glucose, but it also contributes to giving bread its delicious taste. Omer Gokcumen, a leading scientist at UB College of Arts and Sciences, explained: "The idea is that the more amylase genes you have, the more amylase you can produce and the more starch you can digest effectively."

Analysing the genomes of 68 previous humans including an age-old sample from Siberia dating back 45,000 years, the study unraveled that hunter-gatherers before the agricultural era possessed multiple copies of the gene linked to starch digestion capabilities. This points to the notion that a diversity of these genes trekked across Eurasia in humans even before plant domestication and the resultant increase in starch consumption.

AMY1 gene duplications were also noted in Neanderthals and Denisovans, signifying an earlier origin than assumed with Kwondo Kim, a lead author on the study saying: "This suggests that the AMY1 gene may have first duplicated more than 800,000 years ago, well before humans split from Neanderthals and much further back than previously thought."

The findings indicate that early duplications laid down the foundation for genetic variability around the amylase region, setting the stage for humans to adapt their diets as they increasingly consumed starch due to new technologies and lifestyle changes.

The study also reveals that while early hunter-gatherers had multiple gene copies, European farmers experienced an increase in the average number of AMY1 copies over the past 4,000 years, likely due to their starch-rich diets. The research, published in the Science journal, utilised genome mapping and sequencing to detail the AMY1 gene region.