Perhaps think twice about that extra kick of chilli sauce. Research suggests a spicy diet could be linked to cognitive decline and dementia.
A 15-year study of 4582 Chinese adults aged over 55 found evidence of faster cognitive decline in those who consistently ate more than 50 grams of chilli a day – not a lot in some parts of the world.
The risk of memory decline and poor cognition almost doubled, in fact, with the genders affected equally but a higher risk noted for those with a lower body mass index (BMI).
“Chilli consumption was found to be beneficial for body weight and blood pressure in our previous studies. However, in this study, we found adverse effects on cognition among older adults,” says lead author Zumin Shi, from Qatar University.
The researchers – from Qatar, China and Australia – followed the lifestyle and health of their participants over the 15 years, tracking what they ate, their health and lifestyle, and certain abilities such as their memory.
From this, they could determine long-term changes in the group, and correlate that with lifestyle factors. Such longitudinal studies are useful for identifying trends for closer follow-up in later studies, they say.
The reasons for the apparent link between chilli and cognitive function aren’t clear, and they acknowledge that there may be other factors at play. However, one possible hypothesis is that it comes down to capsaicin, the active ingredient in chilli.
“One thing we think [it might be] is that capsaicin may be neurotoxic if too much is consumed,” says co-author Ming Li, from the University of South Australia.
While no chilli has a high enough amount of capsaicin to be harmful, a high dose has been found to be lethal in mice.
However, the researchers agree that it is too early to suggest that reducing or stopping eating chilli can reduce the risk of cognitive decline. More testing is needed first.
The study is published in the journal Nutrients.
Amelia Nichele is a science journalist at The Royal Institution of Australia.
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