Too much chilli could lead to memory loss

Spice might make life more interesting, but too much could negatively affect your memory, suggests a new study from Qatar, China and Australia.

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.

Now 50 grams of chilli a day might sound like a lot by our standards – but it’s a ‘normal’ amount for Chinese adults. In fact, more than 30 per cent of participants actually ate more than 50 grams a day.

“Chilli is one of the most commonly used spices in the world and particularly popular in Asia compared to European countries,” says UniSA epidemiologist Ming Li who co-authored the study.

“In certain regions of China, such as Sichuan and Hunan, almost one in three adults consume spicy food every day.”

Double the risk of memory decline

The study, led by Zumin Shi from Qatar University, showed that those who consumed in excess of 50 grams of chilli a day had almost double the risk of memory decline and poor cognition.

“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,” Zumin says.

The study involved following the lifestyle and health of more than 4500 people for over 15 years, tracking what they ate, their health and lifestyle, and testing certain abilities such as their memory.

From this, researchers could track long-term changes in the group, and correlate that with lifestyle factors.  Such longitudinal studies are useful for identifying trends for closer followup in later studies.

In this study, chilli intake included both fresh and dried chilli peppers but not sweet capsicum or black pepper.

Capsaicin is the active component in chilli which reportedly speeds up metabolism, fat loss and inhibits vascular disorders but this is the first longitudinal study to investigate the association between chilli intake and cognitive function.

Those who ate a lot of chilli had a lower income and body mass index (BMI) and were more physically active compared to non-consumers. Researchers say people of normal body weight may be more sensitive to chilli intake than overweight people, hence the impact on memory and weight. Education levels may also play a role in cognitive decline and this link requires further research.

The link between chilli and cognitive decline is unclear

Now don’t get us wrong, chilli has been shown to have many benefits, such as boosting immunity, reducing hypertension, and weight loss. The researchers have just highlighted a potential link between chilli and declining cognitive function.

While the researchers do propose an explanation for their findings, the reason why chilli could cause declining cognitive function is still unknown.

“High chilli consumption may impact on neuronal viability and, as a consequence, cognitive function. However, this is highly speculative and requires further investigation,” the researchers write.

The researchers also point out that it is too early to suggest that reducing or stopping eating chilli can reduce the decline.

Indeed, the effect could be caused by an unknown factor not accounted for in the study, such as education levels.

To overcome the limitations of an observational study such as this, the researchers suggest that more testing, including random control trials, needs to be done to explore this link between chilli and cognitive function.

The research is published in the journal Nutrients.

This article was first published on Australia’s Science Channel, the original news platform of The Royal Institution of Australia.

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