Recent genetic studies reported in Nature Genetics suggest that human’s ability to digest starchy foods, like the potato, may explain our success on the planet. Compared with primates, humans carry extra copies of a gene, called AMY1, which is essential for making the salivary enzyme amylase that digests calorie-rich starches. The University of California Santa Cruz authors suggest that the starch has been the source of extra calories crucial for feeding the larger brains of humans, rather than meat in the diet, which has been previous conjecture.
Dr Nathaniel Dominy and colleagues argue that meat is the improbable source: “Even when you look at modern human hunter-gatherers, meat is a relatively small fraction of their diet. To think that, two to four million years ago, a small-brained, awkwardly bipedal animal could efficiently acquire meat, even by scavenging, just doesn’t make a whole lot of sense.”
The team studied groups of humans with differing diets and found those with high-starch diets tended to have more copies of AMY1 than individuals from populations with low-starch diets. For example, the Yakut of the Arctic, whose traditional diet centres around fish, had fewer copies than the related Japanese, whose diet includes starchy foods like rice. The researchers believe our earliest human ancestors began searching for new food sources other than the ripe fruits that primates eat. These were starches, stored by plants in the form of underground tubers and bulbs – wild versions of modern-day foods like carrots, potatoes, and onions. In work earlier this year, the team found that animals eating tubers and bulbs produce body tissues with a chemical signature that matches what has been measured in early fossilised humans.
Now you can be even more confident to eat more veg and eat less meat … to develop yourself as well as save the planet.
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