Changes in cooking and farming over the years have contributed to creating a common gene variant which could help people avoid developing type 2 diabetes, researchers have said.
Teams from the University College London (UCL) and Imperial College London say this particular gene has evolved over time and could help keep blood glucose levels low.
However, their study also found evidence to suggest that some people still have an older gene variant, which meant they were more likely to develop type 2 diabetes.
What the findings indicate is that as Western diets high in carbohydrate and sugar have proliferated in recent years, human evolution has changed in kind.
As a result, some people differ in how effectively their bodies can handle higher blood glucose levels in the body.
The London scientists were studying how glucose is transported to muscle and fat, and the process of how insulin reacts after people have eaten. In-between eating, the glucose transporter is kept inside muscle and fat so that it cannot remove glucose from the blood, leading to higher blood glucose.
The moving of the transporter is controlled by a protein called CHC22, which in turn is controlled by a gene. But the evolved version of this gene has made a different variant of the protein.
Almost half of the 2,504 people studied had a variant of CHC22 that is produced by the mutated gene, which became more common as people developed cooking and farming.
The research team found this variant is not as effective at keeping the glucose transporter inside muscle and fat between meals. This means the transporter works better at taking in glucose from the blood, thereby lowering blood glucose levels.
First author Dr Matteeo Fumagalli, who began the study at UCL before moving to the Imperial, said: “The older version of this genetic variant likely would have been helpful to our ancestors as it would have helped maintain higher levels of blood sugar during periods of fasting, in times when we didn’t have such easy access to carbohydrates, and this would have helped us evolve our large brains.”
UCL’s Professor Mark Thomas added: “Our analyses strongly suggest that we have found yet another example of how prehistoric changes in dietary habits have shaped human evolution.
“Understanding how we have adapted to these changes doesn’t only inform us about why people lived or died in the past, but also helps us to better understand the relationship between diet, health and disease today.”
The results have been published in the journal eLife.