What you see: Sprouts growing from your potato’s “eyes.”
What it is: The potato trying to grow new potatoes! But the sprout may have higher concentrations of compounds you don’t want to eat. And sprouting will eventually degrade the texture and flavor of the potato.
Eat or toss? How robust are the sprouts? If they’re just about the size of pen-tips, scrape them off while you’re cleaning the potato. If they’re up to the size of peas, cut them out, including the “eyes” they emerged from. Any bigger, and especially if the potato is softening, and you might want to reconsider what you’re cooking.
Can you eat a potato that’s sprouting?
When a potato starts sprouting, it’s just doing what potato plants do—growing and making more potatoes! And like any good parent, the potato wants its family to stay safe. So, sprouts, which are vulnerable once they emerge from the protective cover of soil, come equipped with insect and disease-deterring defensive glycoalkaloids.
Glycoalkaloids, which can cause gastric distress, headaches and neurological problems if you ingest too much, can also accumulate in potatoes, particularly in the peel, that have been roused from their protective earthen dens and exposed to light (their green color tells you to proceed with caution; more here).
But, not to worry, dear potato eater. You can easily cut out the sprout and the “eye” it emerged from to remove the risk. And even if you do ingest some extra glycoalkaloids, rest assured that they’re harmless, and maybe even beneficial, in small amounts. Trace quantities of glycoalkaloids contribute to how the potato tastes and researchers are even exploring their potential in treating cancer. Plus, as long as your potatoes don’t have any extra bitter flavors—a “tell” of high concentrations of the compounds—you can be reasonably confident that you avoided the glycoalkaloid threat.
Potato sprout size makes a difference
Nora Olsen, potato specialist for the University of Idaho, says she doesn’t worry much about small sprouts; typically, she’ll try to scrape off pen-tip sizes sprouts from potato eyes while she’s cleaning her potatoes. But she doesn’t stress about them, even if some small sprouts remain.
“Little sprouts like this are not adding any major concerns,” she said of the russet potato with the small sprouts pictured below. “I frequently eat potatoes with sprouts like this.”
As the sprouts get bigger, concern about their concentration of glycoalkaloids also increases. And they’ll soften and possibly wrinkle as resources from the tuber migrate to the sprout.
“They’re basically cannibalizing the tubers,” Roy Navarre, a research geneticist at the U.S. Department of Agriculture who specializes in potatoes, told me. “That’s the whole role of the tuber, to provide energy for the sprouts and make a new plants. It’s being converted into energy for the sprouts…If you have a heavily sprouted tuber, the tuber itself is probably going to have high amounts of glycoalkaloids.”
Navarre is comfortable cutting away pea-sized sprouts. Beyond that, it’s a “toss” for him.
“When they start to get longer the taste is probably going to be off,” he said. “The tuber is going to be softer.”
“You’re not going to want to eat a salad of sprouts”
Glycoalkaloids deserve our respect, and we have good reasons to be wary of them in our potatoes, but it’s also worth keeping in mind that it’s only at elevated levels that they can cause problems.
Olsen notes that in the U.S., potatoes are bred to have low glycoalkaloid content, further reducing the risk.
As for those sprouts, it’s hard to say exactly how many it would take to make you ill, but it would be a lot.
“You’re not going to want to eat a salad of sprouts,” Olsen said.
SOURCES:
- Roy Navarre. Research Geneticist. United States Department of Agriculture.
- Nora Olsen. Professor and Extension Potato Specialist. Department of Plant Sciences. University of Idaho
- A Review of Important Facts about Potato Glycoalkaloids. Marita Cantwell. Perishables Handling Newsletter. August 1996.
- G1437 Green Potatoes: The Problem and the Solution. Alexander D. Pavlista. University of Nebraska at Lincoln. 2001.
- Should you be afraid of green potatoes? EatOrToss. Sept. 27, 2017.
- A Review of Occurrence of Glycoalkaloids in Potato and Potato Products. Duke Gekonge Omayio, George Ooko Abong and Michael Wandayi Okoth (Department of Food Science, Nutrition and Technology, University of Nairobi). Current Research in Nutrition and Food Science Journal. Published online Nov. 29, 2016.
- Glycoalkaloids in Foods. Health Canada. Reports and publications — Food and Nutrition
- Steroid Alkaloids. Plants Poisonous to Livestock. Department of Animals Sciences. Agriculture and Life Sciences. Cornell University.
I told you they had eyes in the backs of their potato heads!