What Exactly Are Nightshades and Can You Eat Them?

Nightshades are members of the Solanaceae (Solanum) family, a genus of flowering plants that spans 2,700 species and includes everything from herbs, weeds, fruits, and vegetables. The common traits among them are botanical: the type of flower they sprout, and the arrangement of seeds within their fruit.

Native nightshades can be found on every continent except Antarctica, favoring both tropical and temperate environments. The greatest swath of species grows throughout Australia, Africa, Central America, and South America; scientists recently found a fossilized tomatillo, a green fruit often mistaken for a kind of tomato that grows in a papery husk, in the Patagonian region of Argentina. That means the Solanaceae family has been around since at least 52 million years BCE, likely appearing even into the Mesozoic Era.

One of the defining characteristics of the nightshade family (and the reason for their edgy reputation) are their range of glycoalkaloids, a family of poisonous chemical compounds which have varying negative effects on the human body.

The two glycoalkaloids you come into contact with through foods are solanine and capsaicin.

• Solanine: Low levels of solanine, thought to be a defense mechanism against herbivores, is found in some leaves and stems of common nightshades like tomatoes, potatoes, and eggplant.
• Capsaicin: Capsaicin is what gives hot peppers like habaneros and jalapenos, along with spices like paprika and cayenne pepper, their kick.

Nightshade fruits are packed with lycopene and vitamin C. They include:

• Tomatoes
• Berries like goji berries and garden huckleberries (which are different than regular huckleberries). Though blueberries also contain solanine, they aren’t nightshades.
  
• Tomatillos and ground cherries, also known as cape gooseberries.
• Tamarillos are native to South America and resemble small cranberry-sized tomatoes.
• Naranjillas are small orange fruits native to South America with a tangy citrus flavor described as a hybrid between lime and rhubarb. It’s juice is typically used for a Colombian drink called lulada.
• Pepino, a South American fruit named for its distinct cucumber-melon flavor.
• Eggplants
• Peppers, like bell peppers, chili peppers, and sweet peppers
• Potatoes, including white potatoes along with the red, yellow, and blue varieties. Notably, yams and sweet potatoes are not nightshades, and actually belong to the Convolvulaceae (Morning glory) and Dioscoreaceae families, respectively.

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