New Haven, Conn. – A new study has found that the brain is harder to fool than we think.
Researchers at Yale University School of Medicine found that the brain is not easily satisfied by “energy-less” sweet flavours.
The pleasure the brain derives from consuming something sweet is driven by the amount of energy it provides.
The study found that the brain attributes a greater reward to sugars compared to artificial sweeteners.
Ivan de Araujo, a professor at Yale University School of Medicine, says consuming high-calorie beverages is a major contributor to weight gain and obesity, even after manufacturers introduced artificial sweeteners to the market.
“We believe that the discovery is important because it shows how physiological states may impact on our choices between sugars and sweeteners,” says Araujo.
“Specifically, it implies that humans frequently ingesting low-calorie sweet products in a state of hunger or exhaustion may be more likely to ‘relapse’ and choose high calorie alternatives in the future.”
Araujo adds that the study results suggest combining sweeteners minimal amounts of sugar to achieve a “happy medium.” This way a person’s energy metabolism doesn’t drop and calorie intake is kept to a minimum.
The School of Medicine says the study identified a specific physiological brain signal that is critical for determining choice between sugars and sweeteners.
This signal regulates dopamine levels – a chemical necessary for reward signalling in the brain – and only arises when sugar is broken down into a form where it is usable as fuel for cells of the body to function.
Research was performed in mice, using a combination of behavioural testing involving sweeteners and sugars, whilst measuring chemical responses in brain circuits for reward.
The researchers believe the findings are likely to reflect in humans.
“According to the data, when we apply substances that interfere with a critical step of the ‘sugar-to-energy pathway,’ the interest of the animals in consuming artificial sweetener decreases significantly, along with important reductions in brain dopamine levels,” says Araujo.
“This is verified by the fact that when hungry mice – who thus have low sugar levels – are given a choice between artificial sweeteners and sugars, they are more likely to completely switch their preferences towards sugars even if the artificial sweetener is much sweeter than the sugar solution.”
Now that the team knows that dopamine cells are critical in sugar/sweetener choice, they hope to identify the associated receptors and pathways in the brain.