How The Selectively Bred Perfect Potato Turned Poisonous

By Wesley Fenlon

A friendly bit of advice: if a potato is green, don't eat it.

What could be more harmless, more innocent, than a potato? The common nickname spud makes potatoes sound so ordinary, so dull. They're small, and brown, and not especially tasty until they're coated with butter or fried. Harmless. Unless you eat them green. Then, suddenly, you're looking at possible nausea, diarrhea, headaches, vomiting, and death.

Such is the curse of solanine, an alkaloid chemical in potatoes designed to protect them from harm. It's a classic defense mechanism--potatoes produce solanine to ward off insects and fungi--so the more solanine inside a potato, the more likely it is to survive. Unfortunately, that chemical also makes the potato poisonous.

Photo credit: Flickr user hippie via Creative Commons.

Food researchers ran into solanine problems when they tried to breed a special potato, called the Lenape, back in the 1960s. BoingBoing's Maggie Koerth-Baker has the story. The great thing about the Lenape was its sugar and starch content. Fried into potato chips, it turned a perfect golden brown. The bad thing about the Lenape was that it made people sick. Here's the explanation:

"In 1974, after Lenape potatoes had been recalled from agricultural production and relegated to the status of “breeding material”, the USDA published results of an experiment where they grew Lenape, and five other potato varieties, at 39 locations around the country...The conclusion: Lenape was genetically predisposed towards producing an extraordinarily high amount of solanine, no matter what happened to it during growth and harvest. The average Russet potato, for instance, contained about 8 mg of solanine for every 100 g of potato. Lenape, on the other hand, was closer to 30 mg of toxin for every 100 g of food. That made it nicely resistant to a lot of agricultural pests. But it also explained why some of the people who were the first to eat Lenapes — most of them breeders and other professionals in the agriculture industry — ended up with severe nausea, like a fast-acting stomach bug."

Koerth-Baker goes on to use the Lenape as an interesting example of food modification, and points out that this potato isn't just a prop in a cautionary tale against selective breeding. Classic breeding techniques can produce unforeseen, potentially dangerous or unhealthy results, too. Nevertheless, food modification has created a lot of controversy. The Lenape isn't exactly a poster spud for the merits of engineering better foods, but at least it's not as bad as New Zealand's (organic) killer zucchini.