Q. I’ve heard that foods from the nightshade family are supposed to aggravate arthritis. Is this true? Are some nightshade foods worse than others?
A. Elizabeth Chin, a dietetic intern at Tufts’ Frances Stern Nutrition Center, answers: “‘Nightshade’ plants are a group of plants that fall into the Solanaceae family, and have been historically used as a medicinal herb with varying therapeutic characteristics. There are more than 2,700 species within the Solanaceae family, and caution must be used when choosing foods from this species, as numerous items are toxic to humans and animals. The most commonly eaten nightshade foods include potatoes, tomatoes, sweet and hot peppers, and eggplant.
“The key contents of nightshade plants that can compromise certain functions in the body are alkaloids, protective elements used by nightshade plants to defend against insects and other predators that may eat them. Currently, there is no scientific research that has been able to prove whether the alkaloids present in foods can cause increased joint inflammation, and some evidence only theorizes that alkaloids may cause inflammation or alter enzyme activity in the body. Additionally, the effects of consuming nightshade foods may affect only individuals who are more sensitive to alkaloids, as levels are very low in ripe nightshade foods and there has been no minimum toxic exposure level established.”