8-Methyl-N-vanillyl-trans-6-nonenamide: My Favorite Toxic Chemical

Note: This is my contribution to the "Our Favorite Toxic Chemicals" blog carnival organized over at Sciencegeist.

Amanita muscaria: Naturally
delicious deadly
photo: Pato Novoa

For some time, and not for the first time, there has been a war of words going on between chemists and environmentalists/organic food proponents/hippies/etc.  Both "sides" are right in a lot of ways, but--as is so much the case in public discourse, both are blinded by prejudice.  Chemists: you're not helping by implying that anyone who has concerns about something an idiot (often in so many words--see comments on any number of blog posts regarding Nick Kristoff's recent chemophobia).  Non-chemists: you're not helping either when you use "chemical" as a dirty word.

With the exception, apparently, of some Dow-manufactured products, everything is a chemical, from the water you drink to the air you breathe.  "Organic" (itself another bone of contention between chemists and non-chemists) or natural also doesn't mean better.  Certainly no one would argue that ricin, one of the most toxic compounds known to man, is "better" than aspartame simply because it's a natural product.

Get it? Close to my heart.  Ha!

As a chemist, food geek, and gardener, I had to choose a food toxin for my favorite.  I settled on something near and dear to my heart: capsaicin.  Capsaicin is the most abundant active alkaloid found in chili peppers--it's the stuff that gives them the "heat."  I love the stuff so much I had it inked on my ribs (chemists--I kept the "C"s and "H"s because I thought it looked better, stylistically).

Chemical toxicity is generally expressed as LD50; simply, the dose of a substance required to kill 50% of a test population.  In rats, the LD50 for water is around 90 milliliters per kilogram of body weight; capsaicin's LD50 is 47.2 milligrams per kilogram.  To make that a little more clear, the average American male weight approximately 87 kilograms, and naga jolokia chili contains at most about 62000 mg/kg capsaicin.  This means one would need to eat about 70 grams of naga to die, or about 60 dried pods (very approximate numbers used here).  That is, if you could keep them down; as far as I can tell, there has never been a documented death from capsaicin overdose, from chilis or otherwise.  Note: The two gallons of water you might be tempted to drink after attempting such a feat would likely kill you if the peppers didn't.

So why do I love capsaicin so?  For one, capsaicin stimulates the release of adrenaline.  For starters, unlike many folks, I love the intense feeling of heat, racing heart, and mild dizziness--eating entire chilis is like taking a drug (not that I would know anything about that).  So very many of my favorite foods would be bland, boring dishes without this wonderful molecule.  Imagine Mexican or Thai food without the heat.  Boring.

In ur garden, synthesizin' ur cancer medz
photo by woodleywonderworks

Capsaicin and chili peppers are extremely useful outside of the kitchen, as well.  I've personally used a topical application for nerve pain, and it is often used for all sorts of back, muscle, joint and arthritis pain.  Ointments are also used as a treatment for psoriasis; it reduces itching and inflammation.  Recently, capsaicin is under investigation as a diabetes treatment and a cancer treatment--it induces apoptosis, a form of programmed cell death, in several cancer types.

There are myriad other uses; in the garden spray hot pepper wax to keep away pesky rodentsand deer (it won't keep birds away, they don't respond to it, and are the primary way pepper seeds are dispersed).  Police and military forces us capsaicin--from chili peppers--for less-lethal force applications (India announced they would be using naga jolokia for this purpose).

An old saw is that the dose makes the poison, and it is certainly the case with capsaicin and many other compounds.  The mainstream press would do well to keep this in mind--maybe hire some editors with a science background to at least check facts before rushing to press with another article screaming chemophobia.  The science press (and twittersphere, blogosphere, etc.) would do well to keep in mind that not everyone has as deep an understanding of chemistry as they do, and attempt to educate without mocking.  Remember: natural is not always good, and synthetic is not always better.