What to Know About Nightshade Intolerance

Nightshades are a group of vegetables that belong to the Solanaceae family. More than 3,000 species of plants belong to this group. Common varieties are eggplants, tomatoes, potatoes, and bell peppers.

Some people have an intolerance or allergy to nightshade vegetables. There is limited data to indicate how many people are affected, but having a reaction to nightshades is believed to be uncommon.

Learn more about nightshade vegetables, symptoms of intolerance and allergy, alternatives to nightshades, and tips for eating out.

Nightshade Intolerance or Allergy?

An allergy to nightshades is not the same as an intolerance to nightshades. This is because food allergies and food intolerances are two different conditions.

While intolerances and allergies both cause uncomfortable symptoms, an allergy is much more serious. Allergies can even lead to anaphylaxis, a life-threatening reaction.

Food intolerances affect the digestive system. This happens when the body is unable to digest, or break down, nightshades. This could occur for a number of reasons, including:

• A sensitivity to food additives
• Having a reaction to chemicals that naturally occur in some foods
• Having an enzyme deficiency (lack of enzymes that produce primary bile acids needed to digest food)

In many cases of food intolerance, a person may be able to eat a small amount of the food they are intolerant to (like nightshades) without it causing significant issues.

Having an allergy to food involves the immune system. This is the part of the body responsible for defending it from invaders like germs and toxins. If the immune system identifies a food like nightshades as a threat, it will launch an immune response.

This involves producing an antibody known as immunoglobulin E (IgE). This antibody then tells cells to release chemicals that cause an allergic reaction.

Only a healthcare provider can diagnose a food allergy. If you suspect you are allergic to nightshades, make an appointment with your primary care provider or an allergist.

Popular Nightshades

There are a number of foods that fall under the nightshade category. Popular varieties include:

• White potatoes
• Tomatoes
• Bell peppers
• Eggplant
• Spices like paprika and cayenne

Many vegetables from the nightshade family are a good source of nutrients and antioxidants. They even fight inflammation. This includes:

• Eggplant: Eggplant is a good source of fiber and potassium, as well as an excellent source of magnesium, which helps with nerve function.
• Bell peppers: Peppers are antioxidants and a good source of vitamin C. Studies suggest that spicier bell peppers may also boost metabolism.
• Potatoes: Potatoes are high in fiber and also high in potassium, which helps lower blood pressure. They also contain other minerals as well as B vitamins.
• Tomatoes: Tomatoes are an antioxidant and a good source of vitamins like vitamins C and K.

Symptoms of Nightshade Intolerance

Those who are intolerant to nightshades may experience digestive issues. Symptoms may begin within half an hour of eating food, but in some cases, symptoms can take up to 48 hours to appear.

Possible symptoms of food intolerance include:

• Diarrhea
• Abdominal pain
• Bloating
• Nausea
• Flatulence
• Skin rashes
• Itching

Nightshade Allergy Warning Signs

Unlike an intolerance, symptoms of a food allergy will likely appear within seconds or minutes of ingesting a food.

Food allergy symptoms including:

• Swelling of the face
• Swelling in the throat and mouth
• Itchy mouth
• Tingles in the mouth
• Hives
• Nausea
• Vomiting
• Difficulty swallowing
• Diarrhea
• Pain in the abdomen
• Dizziness
• Feeling light-headed
• Wheezing
• Shortness of breath
• Itchy eyes
• Sneezing

In severe cases of an allergic reaction, a person may experience anaphylaxis. This is a medical emergency and can be life-threatening.

Anaphylaxis can come on suddenly with the same symptoms as those above. In addition, people in anaphylaxis may collapse or experience the following:

• Trouble breathing
• Trouble speaking
• Trouble swallowing
• Swelling in the tongue
• Feeling faint
• Tightness in the chest
  

Allergy Tests

If a primary healthcare provider suspects an allergy, they will make a referral to an allergist, a specialist who diagnoses allergies.

Testing for food allergies may involve a number of approaches. These include:

• A skin prick test: This involves placing a small amount of a suspected food allergen on the skin on the arm or back. The skin is then pricked to allow the food to move beneath the skin. The site of the prick is then examined and if a red or itchy bump appears, allergies may be likely.
• Blood test: This will involve checking for the presence of IgE antibodies produced by the immune system.
• Oral challenge test: In this test, an allergist will give a small amount of a food that may be causing your allergy and observe and treat any allergic reaction. If the initial amount is tolerated, increasing doses will be given until a person consumes a full serving size or until a reaction occurs and is treated.
  

Nightshades and Health Conditions

There have been claims that nightshade vegetables contribute to inflammation and, therefore, are unsuitable for people living with conditions like arthritis, lupus, and cancer.

However, there is no evidence supported by scientific research that shows an association between normal levels of consumption of nightshades and inflammation.

In reality, certain ingredients in nightshades may actually be beneficial for inflammation.

Carotenoids are a nutrient in tomatoes and bell peppers, and anthocyanins are a nutrient found in eggplant. Both of these are antioxidants and actually protect cells when there is inflammation in the body.

The Arthritis Foundation says that nightshades can be a valuable part of the diet for those living with arthritis. People who experience pain due to nightshades, however, should eliminate them from their diet, then reintroduce, and watch for symptoms.

List of Nightshade Alternatives

Those who are sensitive or allergic to nightshades may wish to try some alternatives. These include:

• Substituting cauliflower and sweet potatoes for white potatoes
• Substituting mushrooms for eggplant
• Substituting radishes, zucchini, or celery for bell peppers
• Substituting carrots or beets for tomatoes
• Substituting ground white pepper or black pepper for spices like cayenne pepper, paprika, and red pepper flakes

Adjusting to a Nightshade-Free Diet

It can be difficult adjusting to a new diet, but there are some ways to make eating out and grocery shopping a bit easier.

Eating Out 

When eating out, those with food allergies can take some steps to ensure they are safe.

These include:

• Calling ahead to ask questions about ingredients in dishes
• Looking at the menu ahead of time
• Upon arrival, identifying yourself to the manager and explaining your allergy
• Asking about cross-contamination
• Telling your server about your needs, or asking to speak directly to the chef
• Always carrying an EpiPen
• Having a backup plan in case restaurants can't accommodate your needs
• Considering returning to restaurants that have been understanding and helpful in the past

Grocery Shopping

When grocery shopping, those with an allergy or intolerance should avoid whichever nightshade foods they react to.

Be aware there are numerous varieties of nightshades. For example, peppers are a member of the nightshade family. Those who need to avoid all nightshades shouldn't eat bell peppers, chili peppers, or banana peppers.

Those with an intolerance or allergy should also be aware of nightshades in seasonings like paprika, chili powder, cayenne, and curry powder.

It is important to read labels carefully. Nightshades may be hidden in some ingredients like "spices" or "natural flavors." Potatoes may also be found in foods that list "starch" as an ingredient.

Summary

Nightshades are a group of vegetables. Commonly eaten vegetables in the nightshade family include tomatoes, eggplant, white potatoes, and bell peppers. Some people may experience an intolerance or allergy to nightshades, but these are believed to be rare. Those who suspect they have an allergy to nightshades should see an allergist for testing. Alternatives are available for those who can't tolerate nightshades.

A Word From Verywell

Navigating a food intolerance or allergy can be distressing. But you are not alone. If you are experiencing symptoms that are uncomfortable, consider reaching out to a healthcare provider. If you suspect you have an allergy, it is important to get tested.