Debunking the shade against nightshade vegetables and inflammation
Many people avoid these fruits and vegetables over concerns about inflammation—but scientists argue that we've got it all wrong.
If there’s one category of food that experts say gets unfairly maligned, it’s nightshades.
Some people avoid eating these fruits and veggies—which include eggplant, bell peppers, potatoes, and tomatoes—based on the theory that they can cause harmful inflammation in the body.
The reality is that, for most of us, the opposite is actually true.
“There’s a belief that these are inflammatory but there are things in these fruits and vegetables that make them anti-inflammatory,” says Joan Salge Blake, a clinical professor of nutrition at Boston University and host of the nutrition and health podcast Spot On! “You don’t want to throw this whole category of foods under the bus and demonize them.”
Nightshade veggies and fruits are loaded with vitamins, minerals, fiber, and antioxidants, which neutralize harmful, unstable molecules called free radicals that can cause oxidative stress and damage to cells and other vital structures inside the body; consuming high amounts of antioxidants from food can reduce chronic inflammation in the body.
So where did the idea that it’s harmful to consume nightshades come from? The answer is based on misinformation and erroneous assumptions about certain compounds they contain.
“It’s been frustrating to me over the years why nightshades have been such a persistent concern,” says Nate Wood, an assistant professor of medicine and director of culinary medicine at the Yale School of Medicine. “Like all vegetables, nightshade vegetables are good for us and they lower inflammation. Like all foods, some people may have specific intolerances to them.”
What are nightshades—and how did they get their bad reputation?
Nightshades are from the Solanaceae plant family, which includes more than 2,400 flowering plants. It’s a diverse family of plants—some edible and some not—that includes chili peppers, goji berries, tomatillos, pepino melons, spices derived from peppers like paprika or cayenne, and even tobacco. (Although potatoes are nightshades, sweet potatoes are not.)
Many nightshades contain small amounts of nitrogen-based compounds called alkaloids, such as solanine, which protect the plants from insects, fungi, and other threats to their survival.
Some people believe alkaloids can aggravate inflammatory conditions. “Alkaloids are a category of molecules that are thought to be dirty because they bind to lots of different receptors in the body so they can have lots of different effects,” says Wood.
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And indeed people with certain digestive disorders may be sensitive to the effects of alkaloids. Researchers have suggested that consuming nightshades could be a trigger for worsening gut symptoms associated with irritable bowel syndrome and inflammatory bowel disease. That’s because the alkaloid compounds can potentially make the intestinal lining more permeable as well as activate mast cells in the gut that release inflammatory substances like histamine and cytokines.
Even people who don’t have one of these conditions may be sensitive to certain alkaloids when they’re consumed in large quantities. “It’s very individual—some people can tolerate tomatoes but not eggplant,” says Keith Ayoob, a registered dietitian-nutritionist in New York City and an associate professor emeritus of pediatrics at the Albert Einstein College of Medicine. “Others can tolerate eggplant but not other nightshades. For people who are triggered by them, small amounts here and there may be okay.”
But alkaloids are considered safe when healthy people consume them in normal amounts.
The health benefits of nightshades
In fact, not only are these fruits and veggies safe for most people, they also offer major health benefits.
Specifically, tomatoes are rich sources of vitamin C, folate, potassium, and lycopene (a potent antioxidant). A study in a 2025 issue of the journal Molecular Nutrition & Food Research found that adding tomato purée to a high-fat meal led to reductions in inflammatory markers among healthy men, compared to when they ate the same meal without the tomato purée.
Red bell peppers contain vitamin C, folate, potassium, niacin, selenium, and fiber. Eggplants have plenty of fiber, potassium, and magnesium; plus, they have anthocyanins, which are anti-inflammatory phytochemicals that give the skin its purple color.
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Interestingly, the Arthritis Foundation lists nightshade vegetables such as red and green peppers on its list of the best vegetables for arthritis because they are rich in antioxidants and other nutrients that can reduce inflammation throughout the body, including the joints.
Fruits and vegetables in the nightshade category are staples in health-promoting diets like the Mediterranean diet, the DASH diet, and the portfolio diet.
“Where would Italian food be without tomatoes, green and red peppers, potatoes and eggplant, or Latin American food without chili peppers, tomatillos or paprika?” says Ayoob. “Whole societies have been eating these foods for years.”
How to eat nightshades if you’re worried about alkaloids
If you suspect nightshades are problematic for you—because you experience gas, diarrhea, heartburn, or other forms of gastrointestinal distress after consuming them—the best way to test the proposition is with an elimination diet. For two to four weeks, avoid eating nightshades. “Then slowly add them back to your diet, one at a time, week by week, and see what happens,” advises Salge Blake. “It’s like what you would do with a suspected food allergy.”
Keep in mind: “Cooking will reduce the alkaloid content and that could minimize the effects if they bother you,” Salge Blake says.
When potatoes are green or have sprouts on them, however, that’s an indication that those areas have higher amounts of solanine and could cause digestive distress if you eat them. Wood’s advice is to avoid eating them—compost them instead—“or be generous with cutting out that green area or sprout.”
The bottom line is: Nightshade fruits and veggies deserve a place at the table. “Nightshades get a lot of heat and they’re actually really good vegetables—they’re known for having a ton of nutritional benefits and anti-inflammatory phytochemicals,” says Ayoob. “It’s really important not to eliminate foods you don’t have to.”
