I’ve always thought there was something fundamental to the human identity about our craving for carbs. Scientists and paleontologists have agreed. But not always for the same reasons. Now, re-searchers say they’ve discovered an ancient ‘Sweet Tooth’ gene…
Among other effects of this latest revelation about the universal human craving for carbs may be the destigmatization of having a sweet tooth. But understanding how carb cravings work is also funda-mental to understanding why we tend to over-consume starches…
Sugars-in-waiting
Starches (carbs) are mainly ‘sugars-in-waiting. They’re easily broken down by enzymes in our salyva into sugars that are readily absorbed by the body just like added sugar in junk food and excess natural sugars in foods such as fresh fruits.
Recent research reveals that the roots of our shared sweet tooth may reach as deeply into the past as our Neanderthal ancestors.
What they found
A team at the University of Buffalo shows that the salivary amylase gene (AMY1) may not only have helped shape human adaptation to starchy foods, but may have entrenched itself in the human genome as far back as more than 800,000 years ago, long before the advent of farming.
Some researchers had thought this genetic adaptation had not occurred until after the advent of farming increased exponentially the consumption of carbs as a result of grain cultivation.
How it works
“The idea is that the more amylase genes you have, the more amylase you can produce and the more starch you can digest effectively,” says the study’s corresponding author, Dr. Omer Gokcumen.
Amylase is an enzyme that not only breaks down starch into glucose, but also gives bread its taste.
Using new technology, the researchers analysed the genomes of 68 ancient humans, including a 45,000-year-old sample from Siberia. To their surprise, they found that pre-agricultural hunter-gatherers already had an average of four to eight AMY1 genes per cell. And that directly suggested that ancient humans were already walking around Eurasia with high AMY1 copy numbers well before they started domesticating plants and eating excess amounts of starch.
The takeaway
“The initial duplication of AMY1 was like the first ripple in a pond, creating a genetic opportunity that later shaped our species,” an abstract of the study report explains. “As humans spread across differ-ent environments, the flexibility in the number of AMY1 genes provided an advantage for adapting to new diets, particularly those rich in starch.”
“Individuals with higher AMY1 [gene] numbers were likely digesting starch more efficiently and having more offspring,” Gokcumen says. “Their lineages ultimately fared better over a long evolutionary time frame than those with lower copy numbers, [promoting] the number of higher AMY1 copies.”
My take
It all makes sense to me. And I can also see how this discovery would support the relatively new findings that humans are hard=wired to crave salt, fat sugar and other substanaces, such as alcohol, caffeine and nicotine. Ancient genetic adaptations that are supported by abiding addictive mechan-isms. Or, as other recent studies suggest, a single addictive mechanism that can be triggerd by all the aforementioned addictive substances…
On a more practical level, this new study suggests that those of us feeling marginalized, stigmatized, or otherwise embarrassingly ‘different’, because of our sweet tooth can rest easier. It’s predominantly genentic. And that means it’s not a character flaw or personal failing!
~ Maggie J.