London – It is something we are all guilty of doing from time to time – but beware of raiding your fridge late at night as it could damage your memory, a study suggests.
Digesting food when we are meant to be asleep is thought to play havoc with the hippocampus. Scientists testing the theory on mice found those who were fed during their normal sleeping time were less able to recall receiving a mild shock.
Their long-term memory was also affected, the researchers found. It was already known that eating when we normally sleep can impact health by raising blood sugar levels – which can lead to diabetes and heart problems.
Researchers, from the University of California in LA, set out to see if it also affects mental function. Mice are nocturnal so would normally eat at night. Some were allowed to do so, while the other group were fed in the daytime.
They were all put in a new context and then given a mild shock. When put back in that place the next day, those who had eaten at night as normal showed a “fear response” – indicating they remembered the shock – while the mice who had eaten in the day were less likely to react.
Writing in the journal e-Life, the researchers say this may be because the mice who ate when they usually sleep had reduced levels of a protein called CREB, which is key for the body’s internal clock and the brain’s ability to form memories.
Lead author Dawn Loh said it was “the first evidence that eating at odd hours has far-reaching effects for learning and memory.” The scientists stress that their findings have not been confirmed in humans, but say they could be important for those who stay up late, including shift workers.