You didn’t hear it first from me. Everything is bad for you: alcohol, caffeine, tobacco, meat, fat, sugar, artificial sweeteners, gluten, soy, dairy—continue the list as far as you like.
I learn from The Washington Post that the latest food category to be added to this rapidly metastasizing list is nightshade vegetables: “Nightshades have gotten a bad rap lately on TikTok and celebrity-endorsed detox diets.”
Given their name, it’s not surprising. One member of the category is tomatoes, and they had trouble catching on in Europe four centuries ago because, as a member of the nightshade family, they were feared poisonous. (For this very reason, nightshade control in tomatoes is tricky: whatever kills one is likely to do in the other.)
Other prominent members of the nightshade (or, to be scientific, Solanaceae) family are eggplant, potatoes, and peppers. They contain an alkaloid called solanine, which is poisonous. Of course, the typical nightshade vegetable doesn’t have nearly enough solanine to kill you, but some people claim that nightshades have been causing them digestive upset. They have gotten some relief by cutting these vegetables out of their diet.
This is peculiar in that these exact vegetables play such a large part in the “Mediterranean” diet that is touted as a model of healthy eating. (A friend of mine, returning from Greece: “I got tired of eating nightshades.”)
“Overall, there is no hard evidence that nightshade vegetables are bad for your health,” says WebMD.
“Some preliminary research shows these vegetables may not be the best for people with certain inflammatory and auto-immune conditions like arthritis or inflammatory bowel disease. However, nightshades don’t cause inflammation directly. They may increase inflammation that is already there.”
But nightshades offer many health benefits as well. WebMD: “They contain antioxidants that protect cells from damage due to stress. For example, anthocyanin, the antioxidant that gives eggplant its purple color, can reduce the risk of developing cancer, diabetes, and infections. The antioxidant lycopene, found in tomatoes, may decrease the risk of some types of cancer and heart disease. Nightshades also contain vitamins and minerals that contribute to good health, like Vitamin A and Vitamin C. Eating one bell pepper, for example, gives you your daily allotment of Vitamin C.”
The medical response to those who think they have nightshade sensitivity: cut them out of your diet for a few weeks, and see if you feel any better. One nightshade vegetable that can contain enough solanine to be digestively upsetting to many people is potatoes—particularly the parts that have turned green. Be sure to cut those out. If most of the potato is green, throw it out.
Other tips: peeling potatoes before cooking removes 70 percent of alkaloids. Baking may lower the alkaloid content more than boiling or steaming. It’s a good idea to store potatoes in a cool, dark place to keep them from producing more alkaloids.
In short, nightshades can cause digestive upset in some people, but probably not most, and their health benefits greatly exceed the risk of alkaloid poisoning or upset.
The most alarming aspect of this issue goes beyond the safety of nightshade vegetables: consumers are overwhelmed with all sorts of wild nutritional claims, positive and negative, genuine and unsubstantiated or downright fraudulent. This deluge partly accounts for the dietary crisis in present-day America. Celebrities who insert themselves into the discussion are no help. (Who would go to a celebrity for dietary advice?)
Nutritional news is often so confusing and contradictory that someone might just give up on fruits and vegetables and reach for the Twinkies.