When my friend
Pizza Hacker's asked me whether tomato leaves were safe to eat I decided to delve into this interesting ethnobotanical discussion. Apparently several chefs like the Bay Area's
Chris Cosentino at Incanto,
Heston Blumenthal in the UK, and noted
food scientist Harold McGee have started using a few leaves as flavoring in tomato sauces, much like bay leaves. Given that tomatoes are from the nightshade family that includes such toxic or psychoactive plants as deadly nightshade, potatoes (when they're green), and angel's trumpet or datura, the idea of eating tomato leaves didn't strike me as a good idea. There are unfounded prejudices against tomatos and all the nightshades (eggplant, peppers, tomatillos, tobacco, tree tomatoes) in the West due to the only European nightshades being toxic or psychedelic plants like Belladona or Mandrake root. I am also the founder of the Nightshade Anti-defamation League (NADL) since I think they get an unfair bad rap, so I want to have an open mind about eating this potentially beneficial green.
It worries me that no one in the native range of tomatoes of Central and South America eats the leaves despite that they eat just about every other green in sight. Mexicans figured out how to eat plumeria flowers (considered toxic by most people), use psychoactive datura (kills you with just a tad bit more than what gets you tripping), and the lengthy process of making raw nasty-tasting cacao beans into something delicious, so the fact that they don't eat tomato leaves when they're so abundant and that they eat their close relative's chili greens, tells me something is weird there. It seems if something was edible, the Mesoamericans would've figured out a way to eat it.
One can't ignore the fact that one almost never sees bugs eating tomato leaves as opposed to chili leaves and there is the question of climate. Although the tomatoes in California and NY may be unstressed and their leaves marginally edible, it's unsafe to ignore history and recommend everyone eat them when they may be in hotter climes which stress the plant more and spur it to produce more toxic defense compounds. Given that many foods in small quantities can be fine, but large quantities are toxic (such as apple seeds, onions, and brazil nuts) we should take heed to history of people who have experimented with these plants for thousands of years and know the long term effects. Despite McGee's soothing argument, testing tomato leaves as food on a ruminant such as a cow with a very different physiology from ours or testing one compound, tomatine, on rats is not a good indication of what effect eating the whole leaves on humans would have in the long term. As I'm doing field work in Thailand right now I'm realizing many people eat many plants considered toxic in other cultures, yet they also do not eat any tomato leaves. I think it pays to be cautious and take heed of people who have done long term experiments with these plants rather than a few cursory studies in the last few decades. Eat the delicious tomato fruits, inhale the great smell of the leaves, but get your green flavoring from the hundreds of other delicious herbs we know are safe and nutritious, and avoid the tomato leaves!
I would like to thank Dr. Abby Cuttriss, Dr. Will McClatchey, and Dr. Michael Nee for extensive discussion, information, and encouragement on the topic of tomato leaf toxicity.
What do you think? Would you eat tomato leaves?