Potatoes (Solanum tuberosum) are in the nightshade or solonaceae family. When Linnaeus a noted Sweedish perve, first started classifying plants he did it in part based on the way the flowers looked. If you wonder through a garden, you will notice that tomato, potato and eggplant flowers are remarkably similar. The potato plant even makes little nasty green fruits that look like unripe tomatoes. Don’t eat them.
After the pale people had finished infecting the first invaders of the Americas with various viruses, they returned to Europe with lots of great plants. Tobacco has been a never ending boon for our health and longevity. Thanks Columbus. They also brought back potatoes. Like tobacco these have helped support many a poor family through times of trouble.
Sometimes potatoes turn to the dark side. The potatoes in the image below developed too close to the surface of the soil in my garden. They’re uppity and have ideas above their station. Know your role potato! But these potatoes don’t and as you can see, they’ve decided to throw off the fetters of life as a storage organ. They’ve made chloroplasts, turned green with chlorophyll and they’re going to start making energy on their own.
That’s all well and fine for them, but I’m not going to eat them.
The lovely creamy flesh of the potato is delicious to eat and good for what ails you (if not drenched in trans fats and the like), but the green parts aren’t so good for you.
Potato plants hide their tubers under the ground, storing all that good stuff for later. We (not me and you, but hairless apes) have bred them to be tasty and not poisonous, in the wilds of Peru though the whole damned plant is pretty much not worth eating. Even in the varieties grown in this country, the green parts are loaded with poison. Specifically a-chaconine and a-solanine, two glycoalkyloids that can cause all sorts of symptoms from wretching to death. When a nice scrumptious white potato goes green it starts making these glycoalkaloids.
Even potatoes that aren’t green have between 7.0–68 mg/kg (Friedman et al (2003) Glycoalkaloid and Calystegine Contents of Eight Potato Cultivars Journal of Agricultural and Food Chemistry) of the toxins. The fatal dose for humans is, depending on the authority, between 3 and 6 mg/kg (http://ntp-server.niehs.nih.gov/index.cfm?objectid=6F5E930D-F1F6-975E-7037ACA48ABB25F4). Before your start throwing away potatoes, realize that the first number (7-68) is mg per kg of potato and the second is mg per kg of person. The average consumption in the US is about 0.18 mg/kg/per day — so a good bit under the toxic dose.
The point is, don’t eat yellow snow, or green potatoes.
One rather lovely bit of news: deep frying gets rid of both toxins. Unfortunately it causes the formation of acrylamide.
