The potato plant, a member of the perennial nightshade family, has an interesting secret locked up in its leaves, stems and in those funny looking green spuds. The potato, a starchy tuber from the Solanum tuberosum plant and a dietary staple originating from the Incas of Peru 10,000 years ago, can be deadly if certain parts of the plant are consumed.
This trustworthy food that so often makes it to our tables and restaurant menus has a dark side. The green parts of the plant contain a substance called solanine, a glycoalkaloid poison that is a nerve toxin.
Solanine is a bitter crystalline poison that is part of the potato plant’s natural defense against insects and predators. Any green parts of the plant (its leaves and stem) are naturally high in glycoalkaloids and should not be consumed.
Potato poisoning is rare, but it does happen when people think the plant is as safe as the potato itself and attempt to make a tasty tea from potato leaves. Death normally comes from a lethal coma after a period of weakness and confusion.
The initial symptoms include abdominal pain, diarrhea and vomiting, dilated pupils and vision changes, delirium and hallucinations, and finally loss of feeling leading to paralysis and death. The solanine toxin interferes with the body’s ability to use a particular chemical that facilitates impulse transmissions between cells.
Even the potato itself can be deadly if allowed to turn green. The green hue on such spuds is actually chlorophyll, but evidence of chlorophyll also indicates the presence of high concentrations of solanine toxin. The majority of deaths by potato in the US in the last fifty years have been from drinking potato leaf tea or eating green potatoes.
Although all potatoes contain a small amount of solanine, it’s estimated that a normal-sized person would have to eat about five pounds of potatoes at one sitting to experience any neurological symptoms. A much lesser amount of green potatoes consumed at one time would produce extreme neurological symptoms and possibly death.
Green potatoes occur as a result of exposure of the tuber to light (especially fluorescent lights) and warm temperatures. The best storage conditions for the potato include placing them in a dark place with a temperature between 50 to 65 degrees F. A root cellar is a perfect storage place for the potato but a cool, dark pantry and storing them in a brown paper bag works well also.
Having an occasional green potato chip is not harmful, but it’s best to discard potatoes that have green eyes, sprouts or greenish skins rather than attempting to cut around the greenish parts. The neurotoxin in the green areas may transfer to cooking utensils and the final food product may be contaminated.
So if someone suggests green French fries on St. Patrick’s Day, think twice before deciding that the green hue is merely from food coloring and go for the French fried onion rings instead.
Thoughts? Comments? I’d love to hear them!