Not all nightshade plants are safe to eat.

Nightshade vegetables are members of the Solanaceae family of flowering plants. Most nightshade plants are not edible, such as tobacco and the deadly herb belladonna.

A handful of nightshade vegetables, however, are edible. In fact, they are well-known staples in our diets, including:

  • tomatoes
  • eggplant
  • potatoes
  • peppers

All nightshade plants contain compounds called alkaloids. One alkaloid found in nightshade vegetables, solanine, may be toxic in large quantities or in a green potato.

There’s no evidence solanine is harmful in typical food amounts, though.

Thanks to anecdotal evidence, nightshade vegetables have earned a bad reputation for causing inflammation in the body.

But not everyone with painful joints who eliminates nightshades from their diet experiences pain relief. And some evidence suggests that the nutrition content of nightshades may help with arthritis symptoms.

Keep reading to learn how these vegetables may affect inflammation in the body, their potential health benefits, and more.

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According to the Arthritis Foundation, the belief that eating nightshade vegetables worsens arthritis is a myth. In fact, people with arthritis may benefit from the high nutrition content in nightshades.

For example, researchers in one 2011 study found that inflammation and DNA damage was reduced in healthy men who ate yellow or purple potatoes — which are nightshade vegetables — for 6 weeks.

On the other hand, a 2020 study has shown that for individuals with RA, the solanine in nightshade vegetables may weaken the gut’s barrier causing intestinal permeability or leaky gut.

However, more research is needed. To date, there’s little scientific evidence to draw a conclusion either way.

Most nightshade vegetables contain an abundance of nutrients. They’re also readily available and easy to prepare. In some cases, the benefits of eating nightshade vegetables may outweigh any inflammation risk for those who don’t have an autoimmune disease such as RA.

1. Peppers

Peppers, including bell peppers and chili peppers, are low in fat and calories.

They’re a good source of nutrients such as:

  • vitamin C
  • fiber
  • B vitamins

The capsaicin in chili peppers may relieve arthritis pain by reducing a specific pain transmitter in your nerves called substance P, according to 2016 research.

Capsaicin is a common ingredient in many pain-relieving creams. It may cause mild burning or a skin reaction when applied topically.

2. Potatoes

The white potato often gets a bad reputation because it’s a starchy carb, but all varieties of potatoes are nutritionally dense. They can be a part of a healthier diet when eaten in moderation and not fried or slathered in butter and sour cream.

Potatoes are fat-free and a good source of fiber. Fiber helps to keep you fuller longer so you may eat less. Since they contain sodium and potassium, potatoes also help keep your electrolytes in balance.

They’re also a good source of:

  • vitamin C
  • vitamin B6
  • niacin
  • manganese
  • iron
  • copper
  • folate

The healthiest potato is a baked potato. Add herbs and a dollop of Greek yogurt as a nutritious topping. Don’t be shy about trying different varieties, especially since pigmented potatoes may give you an anti-inflammatory bang for your buck.

3. Tomatoes

Tomatoes contain all four of the carotenoid antioxidants, which include:

  • lycopene
  • beta-carotene
  • alpha-carotene
  • lutein

Lycopene is the most powerful carotenoid. It’s thought to help prevent some types of cancer, help prevent heart disease, and boost immunity. Some research from 2022 has suggested that tomatoes have anti-inflammatory abilities, although more research is still needed.

Nevertheless, solanine in tomatoes may have a harmful effect on RA development according to the previously-cited 2020 study.

Tomatoes are a good source of:

  • vitamin E
  • vitamin A
  • potassium
  • calcium
  • vitamin K
  • vitamin B

Add fresh, diced tomatoes to a green salad or make fresh tomato juice. Tomatoes are delicious in vegetable soup and chili, too.

4. Eggplant

Like tomatoes, eggplant is also a fruit. It has no fat or cholesterol. Eggplant isn’t high in any one vitamin or mineral, but it contains small amounts of most essential vitamins and minerals.

According to one 2015 study, eggplant stalk extract may help reduce inflammation. More research is needed to determine if eggplant fruit has the same abilities. Keep in mind that eggplant may be harmful to individuals with RA because of solanine.

To enjoy eggplant in your diet, go beyond eggplant Parmesan, which has lots of calories and fat. Instead, try sprinkling sliced eggplant with olive oil and herbs, then roasting or grilling them. You can also steam eggplant or add sautéed slices to your favorite veggie pizza.

Learn more: The 8 Most Nutritious Nightshade Plants

For those living with RA, removing or limiting nightshades from your diet may decrease the risk of complications arising from leaky gut syndrome or other gastrointestinal disorders.

To know for certain how nightshades impact you, try an elimination diet. Stop eating all nightshades for 2 weeks to see if your symptoms improve. If you’re not sure, add them back into your diet and see if your symptoms get worse.

Discontinue eating and call your doctor if you experience symptoms such as these after eating any food:

  • tingling mouth
  • rash or hives
  • itching
  • swelling of the face, tongue, or throat
  • difficulty breathing or wheezing
  • gastrointestinal distress

If you develop these symptoms, go to the emergency room or call 911. You may be experiencing anaphylactic shock, which is a serious medical emergency:

  • struggling to breathe
  • sudden feeling of weakness
  • dizziness or lightheadedness
  • fainting

Food intolerances are different from food allergy symptoms, in that they don’t pose an anaphylactic risk. However, can still produce uncomfortable symptoms like pain, discomfort, aches, and gastrointestinal issues.

A dietitian can help you follow an elimination diet to identify and manage any allergies and intolerances.

Many foods are thought to help reduce inflammation in the body. Eating them regularly may help reduce joint pain and swelling. Some popular anti-inflammatory foods include:

1. Omega-3 fatty acids

Foods high in omega-3 fatty acids may help fight inflammation by limiting two proteins that cause inflammation. Omega-3s may also help reduce your risk of heart disease and help lower cholesterol.

Common options include:

  • salmon
  • sardines
  • mackerel
  • flaxseed oil
  • chia seeds
  • walnuts
  • soybeans
  • spinach

2. Produce

Berries, leafy greens, and other fresh produce are chock full of antioxidants. A diet rich in antioxidants helps boost your immunity and may reduce the risk of inflammation. Eating a variety of fruits and vegetables is one of the best things you can do for your overall health.

This may help:

  • prevent weight gain
  • reduce your risk of heart attack and stroke
  • lower blood pressure
  • reduce your risk of some cancers
  • reduce your risk of bone loss

3. High fiber foods

According to the Arthritis Foundation, foods high in fiber — such as nuts, whole grains, and produce — may help respond to inflammation markers common in arthritis. They do this in a few ways:

  • It helps lower C-reactive protein levels in the blood. C-reactive protein has been linked to inflammatory diseases such as rheumatoid arthritis.
  • Fiber may also prevent weight gain, another factor linked to inflammation.
  • Finally, fiber is the meal of choice for healthy bacteria in your gut. Research from 2021 has shown that a healthy microbiome may help reduce inflammation.

4. Olive oil

Olive oil is a staple in the anti-inflammatory Mediterranean diet. According to an older 2011 study, olive oil contains several compounds with anti-inflammatory abilities. One compound, a phenolic compound known as oleocanthal, was shown to have as potent anti-inflammatory abilities as ibuprofen.

5. Onions

Onions contain a bioflavonoid called quercetin. According to one 2016 study, quercetin has anti-inflammatory and antioxidant abilities. It may help prevent an allergic reaction by stopping the release of histamine and mast cell secretion. However, this study is older, and more recent research is needed.

Other foods that contain quercetin are:

  • apples
  • leafy green vegetables
  • beans
  • grapefruit

Not only is it important to add foods that prevent inflammation to your diet, but you should also avoid inflammatory foods.

Foods high in saturated fat and trans fats are linked to inflammation in the body. Some of these items are:

  • fried foods
  • potato chips, crackers, and other processed snack foods
  • processed baked goods, such as cakes and cookies
  • foods cooked at high temperatures
  • foods high in sugar
  • beverages high in sugar, such as soda and sweetened fruit juice
  • foods high in sodium

Certain dairy products may cause inflammation in some people, especially if you are allergic to cow’s milk but other dairy products such as yogurt are associated with decreased inflammation.

To see how dairy impacts your arthritis symptoms, eliminate it from your diet for 2 weeks.

Learn more: Foods to Avoid with Arthritis

It’s OK to add nightshade vegetables to your anti-inflammatory diet. Unless you eat huge quantities of green potatoes, they don’t contain enough solanine to make you sick. And evidence to date does not support a link between nightshades and inflammation.

If you’re concerned, however, talk with your doctor or a dietitian, if you have access to one. They’re the best resource to determine the diet that’s right for you.