Sleep deprivation linked to poor dietary choices
MedWire News: Individuals are more likely to make poor dietary choices when sleep deprived due to activation of reward centers linked to unhealthy food, show findings from two functional magnetic resonance imaging (fMRI) studies.
The findings, presented at the 26th Annual Meeting of the Associated Professional Sleep Societies in Boston, Massachusetts, USA, add to the evidence supporting a link between sleep loss and obesity, which has been shown to be related to changes in appetite and hormone regulation. Indeed, people often report a greater desire for sweet and salty foods following a period of restricted sleep relative to habitual sleep.
"The results shed light on how the brain becomes impaired by sleep deprivation, leading to improper food choices," said Stephanie Greer (University of California, Berkeley, USA), lead author for the first study.
Greer and team performed two fMRI sessions in 16 healthy adults aged 18-25 years, where they rated their current desire for 80 foods after a night of normal sleep and following 24 hours of sleep deprivation. Subjective taste ratings were taken after each scan.
Sleep deprivation was found to significantly impair brain activity in the frontal lobe, the region that controls behavior and complex decision-making such as food selection. However, no significant differences were seen following sleep deprivation in brain areas such as the orbital-frontal cortex, middle insula, and caudate, which are traditionally associated with basic reward reactivity.
"It seems to be about the regions higher up in the brain, specifically within the frontal lobe, failing to integrate all the different signals that help us normally make wise choices about what we should eat," said Greer.
Sleep deprivation significantly decreased the correlation between food desire and taste ratings, indicating a compromised ability to utilize taste value in determining food desire.
In the second study, fMRI was performed on 25 healthy individuals while they looked at images of healthy and unhealthy food choices after 5 nights of restricted sleep (4 hours/night) and habitual sleep (9 hours/night).
Following a period of restricted sleep, unhealthy foods resulted in greater activation of the superior and middle temporal gyrus, hypothalamus, right inferior frontal gyrus, right superior and inferior parietal lobules, and right lateral insula relative to healthy food stimuli.
"The unhealthy food response was neuronal pattern specific to restricted sleep. This may suggest greater propensity to succumb to unhealthy foods when one is sleep restricted," added Marie-Pierre St-Onge (Columbia University, New York, USA), the lead study author of the second study.
By Ingrid Grasmo