A. Judith C. Thalheimer, RD, LDN, managing editor of Tufts Health & Nutrition Letter, answers: “Common members of the nightshade family of vegetables include the peppers, potatoes, and tomatoes you mentioned, as well as eggplants and okra. There is no direct evidence that nightshades are bad for you. There is evidence, as for other vegetables, that they are good for you.
“The negative reputation attached to this family of plants seems to be related to the fact that they contain compounds called solanines, which can cause delirium, hallucinations, and even death in high concentrations. The only plant with concentrations that high is belladonna, which we do not eat. Green patches and sprouts on white potatoes are relatively high in solanines, but you’d have to eat a lot of green potato chips to feel any ill effects.
“There is a widespread idea that solanines cause inflammation and can therefore aggravate inflammatory conditions like arthritis and psoriasis. There is no evidence to support this contention.
“Vegetables are rich in nutrients and fiber that support good health and should make up a large part of every dietary pattern (just don’t count French fries, tots, and potato chips as vegetables). Individuals can be sensitive to different foods and food compounds. If you find cutting nightshades out of your diet helps you feel better, be sure to replace them on your plate with other vegetables.”