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4 Myths You Can Safely Ignore About Nightshade Vegetables

Some popular diets suggest avoiding eggplants, tomatoes, peppers, and potatoes. They're wrong!

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Fresh raw Purple Eggplant in a special wicker basket for Eggplant on gray wooden background. Top view, blank space.Sergey Fatin/Shutterstock

Sometimes even vegetables get a bad rap

Take the nightshade vegetables, or Solanaceae, a plant family that includes eggplant, peppers, potatoes, and tomatoes. (The term “nightshade” may have been coined because some of these plants prefer to grow in shady areas, and some flower at night.) An online search for “nightshade vegetables” yields results linking them to a host of health ailments, from arthritis to migraines. Naturo­paths sometimes recommend that people with arthritis avoid nightshades. And Patricia J. Wales, a naturopathic doctor in Calgary, says naturopaths may suggest that people with osteoarthritis eliminate nightshades. These vegetables are also excluded from certain eating plans. Dr. Joshi’s Holistic Detox—endorsed by Gwyneth Paltrow and Kate Moss—claims nightshades are related to poison ivy and potentially poisonous. “But poison ivy isn’t even in the same plant family,” explains Barry Micallef, a plant biochemistry expert at the University of Guelph. Try this delicious Herbed Eggplant Lasagna.

Why the bad reputation? Some people may think nightshade vegetables are harmful because they’re confusing them with “deadly nightshade” or Atropa belladonna, an inedible weed that’s also part of the Solanaceae family, explains Micallef. Historically, the deadly nightshade has been associated with witchcraft. When ingested in large amounts, it may cause convulsions or even death. But that has nothing to do with these vegetables. Read on to learn the myths about these vegetables that simply aren’t true. Plus, check out more myths about food you need to stop believing.

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View from above of fresh red tomatoes in a wicker basket on a black wooden background. Refreshing vegetables for healthy salads.Alfa Photostudio/Shutterstock

Nightshades contribute to osteo­porosis

Doubtful. Certain macrobiotic diets recommend that people with health challenges avoid nightshade vegetables and that even healthy people should eat them infrequently, says Judy MacKenney, a counselor at the Kushi Institute, a macrobiotic educational institute in Becket, Massachusetts. “Nightshades are high in oxalic acid,” she claims, “which inhibits the absorption of calcium, and can weaken bones and lead to osteoporosis.” But Stephanie Atkinson, a member of the scientific advisory committee for Osteoporosis Canada, says that while oxalates are known to bind calcium in the intestine, reducing calcium absorption, this occurs only when calcium intakes are very low and oxalate intakes very high. Nightshades, however, are not high in oxalic acid, she says. “The alkali contributed by vegetables and fruits is beneficial for bones, as it protects them from using bone to neutralize blood acid.” These are the things that happen to your body when you don’t get enough fruits and vegetables.

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PotatoSea Wave/Shutterstock

They all contain a toxic alkaloid

Not true. Many alternative medicine websites allege that nightshade vegetables contain a toxic alkaloid compound called solanine, a defense mechanism in some Solanaceae plants that protects against natural threats such as insects. It’s true that solanine may develop in raw potatoes, which turn green when they are exposed to light during growth, says Micallef. (That’s why potatoes with green areas should be discarded.) Contrary to the rumors, however, eggplant, peppers, and tomatoes—even the green ones—do not produce solanine and are perfectly safe to eat, he says. Like potatoes, these are the foods you should never, ever eat raw.

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Close Up of an assortment of peppers and chillies in a wicker basket on a rustic wooden surface with three scattered peppers in a ground. Focus on a basket. Top view.vanilla_soup/Shutterstock

Nightshade vegetables worsen arthritis pain

Doubtful. Much of the online discussion concerns nightshades and arthritis, and the notion that eating these vegetables causes an increase in pain or inflammation. But no scientific evidence supports that theory. “I’m not aware of any studies in peer-reviewed journals that prove or disprove that they affect arthritis,” says arthritis expert Mark Erwin, an assistant professor of orthopedic surgery at the University of Toronto. “There are a lot of references to it, but the evidence is mostly anecdotal.” There’s also no scientific reason to avoid nightshades even if you have arthritis, says Pamela Piotrowski, a registered dietitian at the Arthritis Society of Ontario. “Many people have food intolerances. If you start to feel achy every time you eat tomatoes, then maybe, for you, tomatoes are a contributing factor,” she says. But even if your symptoms disappear after eliminating tomatoes, it would be hard to pinpoint them as the cause, since many factors can affect arthritis.

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Bowl and spoon filled with dried goji berries over a wood backgroundJeniFoto/Shutterstock

They cause migraines

No. Linking nightshades to migraines is also without merit, according to Dr. Jonathan Gladstone, director of the Gladstone Headache Clinic and director of neurology at Cleveland Clinic Canada in Toronto. “I am certain that headache experts internationally would be in agreement that there is no evidence that tomatoes, peppers, eggplant, and potatoes cause migraines,” he says. Here are 7 migraine tips you won’t believe you’ve lived without.

The health benefits of nightshades “far outweigh any risks,” says Piotrowski. Tomatoes and peppers are amazing sources of antioxidants that lower the risk of cancer and heart disease, potatoes are high in vitamin C, and eggplant is a source of vitamin K. All are high in fiber. If you do want to eliminate them, make sure you get this nutritional value from other foods. Next, learn about the vegetables that actually do have the potential to be harmful.

Best Health Canada
Originally Published on Best Health Canada