We’ve all done it before; adding too much chili flakes to our noodles or ordering som tum that is too spicy to handle.  The end result: your mouth feels like it's on fire, your face is dripping with sweat, and you wonder why you ever did that in the first place.  So why do we torture and burn ourselves with spicy food, even when the weather is hot?









It has long been held that the hotter the country, the spicier the food, and Thailand is no exception.  This correlation between temperature and the spiciness of cuisine led people to come up with a theory that ‘spicy food leads to perspiration which therefore cools us down in hotter climates!’ or ‘spices are used to cover up the taste of spoiled foods due to hot weather’.  These theories were quickly falsified in a research journal conducted by Billing and Sherman who tested over 4000 recipes from 36 countries and analyzed the 43 spices used and concluded that the reason why people in hotter climates eat spicier foods is because spices are being used as means of preserving food as bacteria and fungal growth have positive relationships with temperature, and that spices have anti-microbial properties (anti-bacterial and anti-fungal) by inhibiting cell invasion and reducing the destruction of red blood cells or haemolytic activity.  Furthermore, a study conducted in 2001 found that among the number of chickens being fed with chilli (containing capsaicin), chickens with the food-poisoning bacteria Salmonella enteritidis reduced by almost half, showing its antibacterial properties.


But why is spicy food still being eaten today, even with refrigeration to slow microbial growth?  It’s because we like it, making humans one of just two mammals to ever seek out spicy food.  Despite our involuntary responses such as sweating and salivating in an attempt to warn the body and dilute the chemical capsaicin which might possibly be harmful.  We, unlike most animals, are able to learn from it that it causes no danger. Secondly, spicy food is still being eaten because of the omnivore paradox which states: despite our attraction to new foods, humans tend to prefer foods they are used to or comfortable with, showing the significance of culture in shaping our habits and how culture is being passed on socially.


Have you noticed that various cuisines have different herbs that taste a different kind of spicy? For example, wasabi has a kind of spice that feels like it's going up your nose and into your brain and is relatively short-lived, whereas the typical Thai chili feels like its setting your mouth on fire.  Unlike the capsaicin in chili peppers which is oil based and tend to cling onto your tongue despite the many glasses of water you take, wasabi or mustard contain a different chemical called allyl isothiocyanate which is hydrophilic, or water soluble and its spiciness can easily be washed down with a gulp.  Additionally, allyl isothiocyanate molecules have very low molar masses and can, therefore, escape up to your sinuses and cause that burning sensation in your nose.


But the thing is, spiciness isn’t actually a taste, it’s a feeling of pain as the different chemicals involved in spices do not stimulate the taste buds, but instead activate sensory neurons called polymodal nociceptor which are the ends of the nerve called the trigeminal nerve which stretches from your brain to different areas of the face.  The polymodal nociceptors are a combination of three types of nociceptors (sensory receptors) which are mechanical, thermal, and chemical. This combination of free nerves causes that burning feeling we get!


It seems that spicy food is here to stay and may even become an alternative to antibiotics in chicken in the future!

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Sources and further reading:

En.wikipedia.org. (2019). Allyl isothiocyanate. [online] Available at: https://en.wikipedia.org/wiki/Allyl_isothiocyanate [Accessed 3 Aug. 2019].


Billing, J. and Sherman, P. (1998). Antimicrobial Functions of Spices: Why Some Like it Hot. The Quarterly Review of Biology, [online] 73(1), pp.3-49. Available at: https://www.journals.uchicago.edu/doi/abs/10.1086/420058 [Accessed 3 Aug. 2019].


Blackmore, S. (2019). Why does spicy food taste hot?. [online] BBC Science Focus Magazine. Available at: https://www.sciencefocus.com/the-human-body/why-does-spicy-food-taste-hot/ [Accessed 3 Aug. 2019].


Bland, E. (2007). Some like it hot: The benefits of fiery food. [online] New Scientist. Available at: https://www.newscientist.com/article/mg19626351-900-some-like-it-hot-the-benefits-of-fiery-food/ [Accessed 3 Aug. 2019].


Eveleth, R. (2014). The science of spiciness - Rose Eveleth. [online] YouTube. Available at: https://www.youtube.com/watch?v=qD0_yWgifDM [Accessed 3 Aug. 2019].


Graves, A. (2001). Chilli-eating chickens repel bacteria. [online] New Scientist. Available at: https://www.newscientist.com/article/dn1171-chilli-eating-chickens-repel-bacteria/ [Accessed 3 Aug. 2019].


Gutierrez, R. and Simon, S. (2015). Why do people living in hot climates like their food spicy?. Temperature, [online] 3(1), pp.48-49. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861184/ [Accessed 3 Aug. 2019].


Ishti (2016). Did You Know That "Spicy" is Not a Taste?. [online] Owlcation. Available at: https://owlcation.com/stem/Did-you-know-that-spicy-is-not-a-taste [Accessed 3 Aug. 2019].


Marczyk, J. (2015). Why Do We Torture Ourselves With Spicy Foods?. [online] Psychology Today. Available at: https://www.psychologytoday.com/us/blog/pop-psych/201508/why-do-we-torture-ourselves-spicy-foods [Accessed 3 Aug. 2019].


Phung, A. (2014). Wasabi. [online] Science and Food. Available at: https://scienceandfooducla.wordpress.com/2014/04/15/wasabi/ [Accessed 3 Aug. 2019].


En.wikipedia.org. (2019). Trigeminal nerve. [online] Available at: https://en.wikipedia.org/wiki/Trigeminal_nerve#Pain-temperature_sensation [Accessed 3 Aug. 2019].

Tang Tae Sakulpanich

Grad 20 student at Bangkok Patana School