Capsaicin: from flavour to flames

The genus Capsicum belongs to a group of around 25 flowering species, part of the nightshade family Solanaceae. Native to the Americas, and cultivated worldwide for their fruit ranging from sweet to spicy, it is an essential condiment in every kitchen.

First isolated in 1816 by Christian Bucholz, capsaicin is a colourless crystalline compound abundant in hot peppers. Concentrated around the seeds of the fruit, it plays a significant role in its spicy flavour. It is an organic compound in the lipid group with a phenol, ether, amide and alkene functional groups.

So how does capsaicin give the infamous fiery flavour of hot peppers? Capsaicin molecules bind to complementary pain receptors on the tongue, mouth and the back of the throat. This triggers nerve impulses to travel to the brain and interpret the sensation as heat.

Relieving this burning heat also requires an understanding of the chemical composition of capsaicin. Drinking water after eating spicy food has little to no effect are water is a polar solvent. Capsaicin has a long hydrocarbon chain which is non-polar and would only dissolve in non-polar solvents. This is why drinking milk or eating ice cream is a better option as they contain non-polar molecules such as casein. Casein will attract the capsaicin molecules, dissolving them and washing them away from the pain receptors.

In contrast to capsaicin's reputation for causing pain, it has vast medical uses, such as in pain-relief medication. Capsaicin interacts with a nerve receptor called TRPV1 found in the brain, peripheral and other areas to decrease the sensation of pain. This can be useful for people suffering with arthritis, diabetic nerve pain and postherpetic neuralgia.

In addition capsaicin's anti-inflammatory qualities may improve heart health; a significant decrease in risk factors of heart disease have been found after 3 months of taking capsaicin. There is also speculation of capsaicin contributing to weight loss by triggering higher metabolism when consumed. However, sufficient doses of capsaicin for weight loss may have side effects when ingested making it counter-effective. Side effects may include nausea and vomiting, diarrhoea and acid reflux, especially in those more sensitive to capsaicin.

So we've seen capsaicin's marvellous mysteries, both in the kitchen and in medication. Nature has fascinating science hidden in every corner, not always obvious to the human eye. I'll see you in the next upload, bye!