Are green potatoes poisonous?
Whether fried, boiled, roasted or baked few foods seem so innocent as the potato. Let’s face it, potatoes are pretty bland, but beneath that mild-mannered exterior lurks the heart of a killer. Under the right conditions potatoes can be quite poisonous.
This will seem less surprising if you know anything about the humble spud’s relations. The family includes not just familiar foods like the tomato and the eggplant, but also nasties like deadly nightshade and mandrake. Part of the reason the potato was so slow to take off in Europe after its introduction from South America was the plant’s striking resemblance to deadly nightshade above ground. And while nightshade’s deadliness is scary enough to us moderns, back then it was also associated with the devil and black magic.
The tendency to poison runs in the family, unfortunately. The culprit is solanine which is actually a catch-all term for a group of chemicals called glycoalkaloids found throughout the potato family. Solanine is present in most potatoes at low levels, but sometimes those levels rise into the range where they become toxic. Symptoms of potato poisoning include headache, rash, vomiting, diarrhoea, weakness and depression and can run to convulsions, breathing problems, coma and — very rarely — death.
Solanine is found throughout the potato but it is particularly concentrated in sprouting eyes and green parts and more concentrated in the skin than inside the tuber. Cooking doesn’t really affect it so the best way to stay out of trouble is to avoid the bad potatoes. That’s not as easy as it sounds: green skin is often associated with increased solanine, but the two don’t always go together.
Mind you, if potato poisoning was common then I wouldn’t be writing about it. Potatoes are something like the fourth biggest crop in the world and for all those spuds there have been only a few cases of poisoning.
The practical risk of poisoning is very low but you should still use your common sense. It’s wise to avoid green potatoes or you might end up feeling distinctly green about the gills.