People’s brains work harder when they drink a small amount of sugar, however old they are – and older people feel happier and have better memory, too.
Scientists say having more energy available for the brain to use can make people feel more motivated to work hard and give them higher self-confidence, which can in turn improve their mental performance.
And even though people are proven to be putting in more effort because their blood sugar is higher, they do not feel like they are trying harder, the study said.
The researchers suggest their findings could help shape food recommendations for people trying to improve their brain performance into old age.
Experts at the University of Warwick said a small amount of sugar can improve memory in over-65s, motivate them to work harder and put them in a good mood.
Short-term energy in the form of raised blood sugar levels could be an important factor in older adults’ motivation to perform a task as well as they can, they said.
To make the discovery researchers gave people a drink with a small amount of glucose – sugar – and made them perform memory tasks.
They found it improves memory, mood and concentration in people over 65 when compared with those who drink an artificial sweetener.
But, in the study, the same people who saw their performance improve did not feel like they were trying any harder.
While people aged 18 to 27 also try harder after drinking the sugar – though they do not feel like they are working more – their mood and memory are not improved.
The researchers say trying hard at difficult tasks into old age is a key way to stave off brain decline, and sugar could be a way of motivating people to keep challenging themselves.
Study team member Konstantinos Mantantzis said: ‘Over the years, studies have shown that actively engaging with difficult cognitive tasks is [necessary] for the maintenance of [brain] health in older age.’
The glucose boosts motivation which then increases older adults’ self-confidence, improves their mood, and makes them feel like they are using less effort. Co-author Dr Friederike Schlaghecken said: ‘Our results bring us a step closer to understanding what motivates older adults to exert effort and finding ways of increasing their willingness to try hard even if a task seems impossible to perform.’
Participants in two age groups – between 18 and 27, and 65 and 87 – took part in the study and were given either a glucose drink or a placebo then asked to perform various memory tasks.
The researchers measured participants’ levels of engagement with the task, their memory score, mood and their own perception of effort.
The team now says more research is needed to understand how energy affects brain engagement, and to develop dietary guidelines for older adults.
The findings are published in the journal Psychology and Ageing.