At Thanksgiving, a family friend used to warn us to never eat sweet potato skins. This November, when I found myself in the yearly ritual of warning friends of the dangers of sweet potatoes, I decided it was time to track down this factoid once and for all.
According to Toxicants Occurring Naturally in Foods (National Academy of Sciences, 1973), sweet potatoes can churn out a bunch of nasty chemicals in response to fungi and other foes. I haven’t found any reference to skins, although it makes sense that this would be the front of the fungus versus sweet potato war.
These chemicals include ipomeamorone, which has caused serious liver damage in animal studies, and other toxins that have caused lung problems among herds of animals that have eaten moldy sweet potatoes. But I didn’t find any mention of people having sweet potato problems (maybe we’re less likely to binge on moldy tubers?).
Looking at ipomeamarone levels in sweet potatoes from the supermarket and toxicity data, it looks like one good-lookin’ potato could kill . . . about a seven-pound weakling. (But could liver damage perhaps accumulate over a lifetime of consistent skin-eating? I don’t know.) People are still studying ipomeamarone today.
Apparently baking your sweet potatoes won’t completely rid them of creepy chemicals, so I guess I’ll make sure that any I ingest are free from signs of disease. And I’ll probably skip the skins.