Caffeine, a psychostimulant commonly used to combat high sleep pressure on a daily basis, alters gray matter structures; however, the effect appears to be temporary, according to new research from the University of Basel.
Lin et al. examined whether daily caffeine intake affects human gray matter through the mediation of homeostatic sleep pressure. Image credit: Bru-nO.
“Caffeine is the most commonly used psychostimulant worldwide and mainly consumed in forms of coffee, tea, energy drink, and soda,” said lead author Professor Christian Cajochen from the Centre for Chronobiology at the University of Basel and colleagues.
“Although caffeine is mostly considered to be nonaddictive, the observed physical and psychological dependence consolidate its regular consumption through the caffeine-induced reinforcing effects, as well as the motive to resist withdrawal symptoms and to increase alertness.”
“Higher alertness after acute caffeine intake mirrors a reduced homeostatic sleep pressure, which is also evident in a reduced depth of sleep.”
“We hypothesized that, through the impacts on sleep homeostasis, daily caffeine intake alters gray matter structures.”
The researchers examined the impact of 10-day caffeine (3 × 150 mg/day) on gray matter volumes and cerebral blood flow compared with 10-day placebo.
The study involved a group of 20 habitual caffeine consumers (average age – 26.4 years, self-reported daily caffeine intake – 474.1 mg/day).
At the end of each 10-day period, the scientists examined the volume of the subjects’ gray matter using fMRI.
They also investigated the participants’ sleep quality in the lab by recording the electrical activity of the brain (EEG).
They found that the subjects’ depth of sleep was equal, regardless of whether they had taken the caffeine or the placebo capsules.
But they saw a significant difference in the gray matter, depending on whether the subject had received caffeine or the placebo.
After 10 days of placebo the volume of gray matter was greater than following the same period of time with caffeine capsules.
The difference was particularly striking in the right medial temporal lobe, including the hippocampus, a region of the brain that is essential to memory consolidation.
“Our results do not necessarily mean that caffeine consumption has a negative impact on the brain,” said co-author Dr. Carolin Reichert, also from the Centre for Chronobiology at the University of Basel.
“But daily caffeine consumption evidently affects our cognitive hardware, which in itself should give rise to further studies.”
“In the past, the health effects of caffeine have been investigated primarily in patients, but there is also a need for research on healthy subjects.”
“Although caffeine appears to reduce the volume of gray matter, after just 10 days of coffee abstinence it had significantly regenerated in the test subjects.”
“The changes in brain morphology seem to be temporary, but systematic comparisons between coffee drinkers and those who usually consume little or no caffeine have so far been lacking.”
The findings were published February 15, 2021 in the journal Cerebral Cortex.
_____
Yu-Shiuan Lin et al. Daily Caffeine Intake Induces Concentration-Dependent Medial Temporal Plasticity in Humans: A Multimodal Double-Blind Randomized Controlled Trial. Cerebral Cortex, published online February 15, 2021; doi: 10.1093/cercor/bhab005
Source link: https://www.sci.news/medicine/daily-caffeine-intake-changes-gray-matter-09385.html
