Fruits and vegetables from the nightshade family are staple foods for many people. Nightshades are nutritious foods, and the idea that they cause inflammation does not have support from scientific evidence.

Nightshade foods contain solanine, a chemical that some people believe may aggravate arthritis pain or inflammation. However, the Arthritis Foundation (AF) says that this is untrue. That said, if a person feels that certain foods, such as nightshades, trigger their arthritis symptoms, they should avoid them.

In this article, we discuss the effects that nightshade vegetables might have on inflammation and arthritis symptoms, the health benefits of nightshades, and which other foods may have anti-inflammatory effects.

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Nightshade vegetables are part of the plant family Solanaceae. Some species are toxic, including the belladonna plant, which is also called deadly nightshade. However, humans commonly cultivate and eat other species.

Common nightshade vegetables that we eat include:

It is important to note that nightshades contain alkaloids, such as solanine, which is toxic in high concentrations.

Solanine is present in trace amounts in potatoes and is typically safe. However, the leafy stalks of the potato plant and green potatoes are toxic, and eating green potatoes can lead to poisoning.

According to Versus Arthritis in the United Kingdom, there is no evidence of a link between nightshade vegetables and inflammation. People in particular often blame tomatoes for worsening arthritis symptoms.

Nightshade vegetables contain many health-promoting compounds, such as lycopene and beta carotene in tomatoes and anatabine — an alkaloid compound in peppers, potatoes, tomatoes, and eggplant. According to a 2020 article, anatabine has powerful anti-inflammatory effects.

However, a 2020 study suggested avoiding certain nightshade vegetables in an anti-inflammatory diet. Nightshade vegetables, such as potatoes, tomatoes, and eggplants, contain solanine. This substance may increase the leakiness of the intestines and affect the gastrointestinal microbiota, indirectly increasing the inflammation relating to arthritis.

A 2021 review suggests that eating purple potatoes may, in fact, reduce inflammation and DNA damage. These species contain high levels of antioxidants, which may prevent cell damage.

Potatoes also contain high amounts of chlorogenic acids (CGA), which may help reduce high blood pressure and the risk of type 2 diabetes. Red and purple potatoes have greater amounts of CGA than white potatoes.

Despite this, if a person believes that they may have a food intolerance or food allergy to nightshades, they can remove them from their diet and note the effects they have on their symptoms.

If a person wishes to eliminate nightshades from their diet, they can replace them with other nonnightshade vegetables, such as:

Certain nightshade vegetables can be high sources of nutrients, including vitamins, minerals, and fiber.

Eating a varied diet rich in vitamins and minerals can have a powerful effect on a person’s health and improve the symptoms of chronic conditions, such as rheumatoid arthritis.

Nutritious nightshades include the following:

  • Eggplant: This is a popular ingredient in many diets, including the Mediterranean diet. Most grocery stores sell eggplant, which is a high source of fiber, potassium, and vitamins B1, B6, and K.
  • Tomatoes: These are a very high source of vitamins and minerals, including vitamins C, A, and K. They also contain the antioxidant lycopene, which may reduce inflammation.
  • Potatoes: Purple, white, and yellow potatoes all offer nutritional value that includes fiber, vitamin C, and vitamin B6.
  • Peppers: Bell peppers are high sources of vitamins A and C, potassium, and folate.

According to the AF, there is no specific diet that a person with rheumatoid arthritis should follow, but some foods can help control inflammation. Many of these foods are in the Mediterranean diet.

Anti-inflammatory foods that the AF recommends include:

  • Oily fish: These are high in omega-3 fatty acids, which have anti-inflammatory effects on the body. Suitable sources include salmon, tuna, and anchovies.
  • Colorful fruits and vegetables: Examples include blueberries, cherries, kale, and broccoli, which are full of antioxidants to support the immune system.
  • Nuts and seeds: Nuts, such as walnuts, pine nuts, and almonds, contain anti-inflammatory compounds, including certain fatty acids.
  • Olive oil: Olive oil contains antioxidants, monounsaturated fat, and the compound oleocanthal, which can reduce inflammation and pain.
  • Beans: Examples of beans include black beans, pinto beans, and kidney beans, which contain anti-inflammatory and antioxidant compounds.

Incorporating these foods into recipes and daily meals is achievable with various recipes available online and in cookbooks.

Learn more about the health benefits of beans here.

Allergies to nightshade vegetables, such as potatoes and tomatoes, are uncommon but possible. However, some people may be sensitive or intolerant to certain foods rather than allergic. Symptoms of food intolerance include:

  • flushed skin
  • a raised red, itchy rash on lighter skin
  • a raised, itchy rash on darker skin
  • eczema flares
  • abdominal pain
  • diarrhea
  • bloating
  • stomach cramps
  • constipation
  • runny nose
  • breathing difficulties
  • wheezing
  • headaches palpitations

If a person is allergic to a certain food, they may develop a severe reaction called anaphylaxis.

Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:

  • hives
  • swelling of the face or mouth
  • wheezing
  • fast, shallow breathing
  • a fast heart rate
  • clammy skin
  • anxiety or confusion
  • dizziness
  • vomiting
  • blue or white lips
  • fainting or loss of consciousness

If someone has these symptoms:

  1. Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
  2. Dial 911 or the number of the nearest emergency department.
  3. Lay the person down from a standing position. If they have vomited, turn them onto their side.
  4. Stay with them until the emergency services arrive.

Some people may need more than one epinephrine injection. If the symptoms do not improve in 5–15 minutes, or they come back, use a second pen if the person has one.

Learn more about nightshade allergies here.

Nightshade vegetables are very high sources of nutrition, and no research to date has linked them specifically to increased inflammation or other arthritis symptoms.

However, some people may have sensitivities or food allergies involving the nightshade family. Eliminating these foods may help those with sensitivity find relief from their symptoms.

A person should speak with a dietitian if they have concerns about a particular food’s effects on their health.