After a long weekend of staying up late, drinking merrily and enjoying the company of many close friends I found myself being a little under the weather. This is pretty atypical for me as I’ve only ever had the flu twice and I usually pass through the cold season relatively unscathed. Whilst there’s thousands of possible reasons for this I’ve always found that should I find myself in the beginnings of an infection a strong dose of chilli seems to make it subside, or at least take my mind off it long enough to start feeling better. I realised yesterday that whilst I might have some anecdotal evidence to support this I hadn’t really looked into the science behind it and the stuff I uncovered in my search has been pretty intriguing.
For starters there are some strange experiments out there that have used chilli (well the chemical that gives it the burn, capsaicin) as an apparently reliable method to induce coughing in test subjects. The first one I came across was testing whether or not coughing is a voluntary action and the results seem to indicate that the coughing we get with the common cold is a mixture of both. Other experiments showed that people with an upper respiratory tract infection (which includes things like the common cold) are more prone to coughing when exposed to a capsaicin/citric acid mixture. None of these really helped me in understanding whether or not chilli aids in reducing the symptoms of the common cold or helping to cure it but a couple other studies do provide some potential paths for benefits.
Subjects with perennial rhinitis, a permanent allergic reaction to stimulus that doesn’t vary by season, showed a marked decrease in nasal complaints when treated with a solution of 0.15mg of capsaicin per nostal every 2nd or 3rd day for 7 treatments. The benefits lasted up to 9 months after the treatment and incredibly there were no adverse effects on cellular homeostasis or overall neurogenic staining (which sounds rather impressive but is a little out of my league to explain). Whilst this doesn’t directly support the idea that consumption helps the common cold it does provide a potential mechanism for it to relieve symptoms. However how much capsaicin ends up in your sinuses while eating it isn’t something I could find any data on.
Other studies have found similar effects when capsaicin solutions have been sprayed into the nasal cavity with the improvements lasting for up to 6 months. That particular study was a little on the small side though with only 10 patients and no controls present but the result do fall in line with the previous study which had much more rigorous controls. The theme appears to resonate through most of the other studies that I could find: topical application in the sinuses is good, inhaling it will cause you to erupt in a coughing fit.
Anecdotally that seems to line up with the experiences I’ve had and it’s good to see it backed up by some proper science. As for consumed chilli helping overall however there doesn’t appear to be any studies that support that idea but there are potential avenues for it to work. So like many scientists I’ll have to say that the results are interesting but require a lot more research to be done. Whether it’s worthy of investigating is something I’ll leave up as an exercise to the reader, but I’m sure we’d find no shortage of spice loving test subjects who’d be willing to participate.