The Lenape potato, developed in the 1960s for the snack business, made a damn fine potato chip. Unfortunately, it was also kind of toxic.
Despite an almost boring reputation as the squishy white bread of the plant kingdom, potatoes actually come from somewhat nasty roots. Their closest relatives are innocuous enough. Potatoes have strong genetic ties to tomatoes and eggplants. But their more distant cousins include tobacco, chili peppers, deadly nightshade, and the hallucinatory drug-producing flower, datura.
This is a phylogenetic family that is ready to throw down, chemically speaking. Called Solanaceae, its members are known for producing a wide variety of nitrogen-rich chemical compounds, called alkaloids. Nicotine is an alkaloid. So are caffeine, cocaine, and a host of other plant-derived chemicals that humans have taken a liking to over the millennia. Depending on the dose, and on the specific compound, alkaloids can have effects ranging from medicinal, to far-out crazy hallucinatory, to deadly.
Potatoes produce an alkaloid called solanine. All potatoes have it, and it’s a feature, not a bug — at least as far as the potato is concerned. Like a lot of other plant-produced alkaloids, solanine is a natural defense mechanism. It protects the potato from pests. Think of potato blight, the fungus-like disease partly responsible for the Irish Famine of the 19th century. The more solanine a potato contains, the less susceptible it is to blight. When a potato is put into a compromising situation — when it’s young and vulnerable, for instance, or when tubers get uncovered and, thus, more exposed to things that might eat it — solanine production can rev up.
Those triggers aren’t always the most convenient for the potato’s human predators. A sudden frost, for instance, can stunt the growth of tubers and promote the growth of vines and leaves, which mimics a younger stage of development and is accompanied by higher solanine concentrations. And if you leave potatoes exposed to the sun for too long after harvest, they start reacting as though they just got accidentally uncovered. They turn green and they produce more solanine. This is actually why you’re not supposed to eat green potatoes. Those spuds, and especially their skins, are rich in solanine. How much solanine varies; it might just be enough to make your stomach a little upset. Or, it could lead to serious illness accompanied by vomiting, diarrhea, loss of consciousness, and convulsive twitching. In very rare cases, people who ate green potatoes have even died.