Lisbon, Aug. 4, 2026 (Lusa) - Caffeine mitigates memory loss and improves other cognitive impairments caused by brain inflammation resulting from excess weight, according to a study carried out by researchers at Portugal's NOVA Medical School, published on Tuesday.
The research, led by Sílvia Conde, a lecturer and principal investigator at NOVA Medical School, and published in the scientific journal "Pharmacological Research", establishes, for the first time, a direct link between caffeine consumption and a reduction in the effects of obesity on the brain, such as memory loss, learning difficulties and other cognitive impairments, according to a statement from NOVA Medical School.
To carry out the study, the researchers used 31 male Wistar rats, divided into three groups. One group was fed a normal diet; another was placed on a high-fat, high-sugar diet for 25 weeks; and a third group received the same diet but with caffeine added to their drinking water during the final 11 weeks of the experiment.
The researchers analysed the effects of chronic caffeine consumption in rats fed a high-calorie diet rich in fat and sugar, used to induce obesity and metabolic changes.
They observed that the animals on the high-calorie diet developed greater weight gain, insulin resistance, changes in glucose tolerance and poorer performance in memory and cognition tests. These animals also showed increased markers associated with neuroinflammation and alterations in neuronal activity in the hippocampus.
In the animals that received caffeine, several of these changes were attenuated, with a reduction in signs of brain inflammation, improved insulin sensitivity and better results in tests assessing spatial memory, recognition and learning.
«We found that caffeine reduces neuroinflammation, but also promotes neuronal activity in the hippocampus, which helps to explain the effects observed on memory and cognition,» says Sílvia Conde, quoted by NOVA Medical School in a press release.
Adriana Capucho, the PhD student at the institution and author of the study, compares the process to the workings of a library.
«If the brain were a city and the hippocampus the ‘central library', where all our memories are stored, obesity would be the pollution that damages the library. Inflammation of the hippocampus is all the accumulated smoke and rubbish. So, caffeine would be the cleaning and maintenance team; in other words, it reduces the ‘pollution' and helps the systems to function better (neuronal activity), allowing the library to operate efficiently once again,» she explained.
The study's authors point out that, in a context where obesity continues to rise globally and its consequences extend far beyond cardiovascular and metabolic diseases, the findings provide a better understanding of this public health issue by linking lifestyle, inflammation and brain health.
Based on the knowledge that obesity is associated with memory and cognitive decline resulting from neuroinflammation, and that caffeine is known to improve alertness and brain function, the research team developed the hypothesis that this substance could protect the brain.
The team believes that the results could contribute to future research into strategies for preventing or mitigating obesity-related cognitive decline, should they be confirmed in clinical trials.
According to NOVA Medical School, this is the first time that the relationship between these three factors (obesity, caffeine and cognition) has been described in a study.
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