Scientists have discovered that prolonged exposure to cold temperatures and eating chili peppers can help to prevent people putting on weight as they get older.
In a ground-breaking study from Japan, it has been shown that both cold and a chemical found in the peppers have similar effects in building up levels of BAT (brown adipose tissue), which helps regulate the way the body expends energy.
BAT is a kind of tissue that exists in all babies, found around the neck and chest, but which gradually breaks down as adults get older. This rate varies between people, and previous studies have proven there is a link between BAT levels dropping off and age-related weight-gain setting in.
This is the first time anyone has been able to prove BAT levels can be made to recover once lost. Scientists exposed test subjects to moderately low temperatures, around 17°C, for two hours every day over six weeks.
When compared to a control group that went about their lives as normal, those subjected to cold showed increased levels of BAT – and also lost around 5 per cent of their body fat.
While this might seem a fairly obvious outcome as the test subjects’ bodies work harder to keep warm, what was really surprising was the similar effect on BAT of consuming “capsinoids”, found predominantly in sweet chili peppers.
Capsinoids have been shown to activate temperature sensors in the gut – similar to the way hot-tasting chilies impact sensors in the mouth.
Those studied who ate large quantities of peppers were also seen to experience increases in BAT tissue – though they didn’t, yet, lose body fat. Researchers speculated that a longer study would likely show genuine weight loss to go with the recovery of BAT.
Lead researcher and report author Takeshi Yoneshiro, from the Hokkaido University Graduate School of Medicine in Japan, said: “Our results showed that human BAT could be recruited even in individuals who had lost BAT, thereby contributing to body fat reduction. This is the first report of successful recruitment of BAT leading to reduced body fat in humans.”
He added that capsinoids appear to induce so-called “brown fat” in the same way as cold by “capturing” the same cellular system that the body’s nervous system uses to increase heat production.
The study was published in the Journal of Clinical Investigation.