What Are Nightshades? List & Impact on Autoimmune Issues

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Nightshades are a group of foods belonging to the Solanaceae family (in the Solanum genus) that are generally classified as a healthy part of a balanced diet. However, for people who suffer from autoimmune diseases, the lectins and small amounts of alkaloids in nightshades can worsen their symptoms.

Below, we’ll discuss why they are called “nightshades,” as well as a list of common edible nightshades that people with autoimmune diseases should avoid.

Are nightshade foods bad? According to a 2023 review, nightshade foods may cause inflammation that may aggravate symptoms of IBS and IBD. Other autoimmune conditions may also flare up when consuming nightshades. 

However, for most people without autoimmune diseases, these are typically safe and healthy foods.

Adhering to an elimination diet is the best medical advice to determine if your body reacts poorly to nightshades.

If you’re in Colorado, searching for a fresh perspective on your autoimmune health or science-based dietary tips, schedule a free phone consultation with PrimeHealth. We have helped countless people treat the root causes of their conditions.

Why Are They Called Nightshades?

The term “nightshades” refers to a group of plants which includes tomatoes, potatoes, peppers, and eggplants. It is possible they were given this nickname because many of these plants bloom in the nighttime. 

It also may have originated from historical anecdotes surrounding certain deadly nightshades.

For example, ingesting even small amounts of the nightshade “belladonna” leads to severe toxicity, causing symptoms such as delirium, blurred vision, and even death. While many nightshades are safe and nutritious for consumption, the nickname persists.

List of Nightshade Foods

Most people eat nightshade foods as a part of their balanced diet with no problem, but some are sensitive to the lectins and alkaloids. For these people, eating nightshades could lead to autoimmunity and inflame preexisting autoimmune issues.

For those with preexisting autoimmune diseases, we recommend eliminating nightshades from your diet.

Nightshades are mostly fruits and vegetables but also include spices and tobacco. You may hear “nightshade vegetables” and “nightshade fruits” as separate groups, but they are essentially the same thing: foods with higher-than-typical levels of alkaloids.

The most common types of nightshade foods include:

  • Tomatoes and tomato products (ketchup, hot sauces, soups)
  • Tomatillos
  • Potatoes (white potatoes, red potatoes, (young) green potatoes, but not sweet potatoes or yams)
  • Peppers (bell peppers, banana peppers, chili peppers, but not black pepper)
  • Eggplant
  • Sunberries
  • Goji berries
  • Groundcherries (not regular cherries)
  • Red spices (cayenne pepper, paprika, red pepper)
  • Ashwagandha
  • Tobacco

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Notably, you may have a potato sensitivity but not a nightshade sensitivity. Potatoes contain multiple potentially harmful proteins and chemical compounds that may impact autoimmunity: solanine, lectin, chaconine, patatin, and a bunch of carbs.

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Are onions nightshades? No, onions are not nightshades. They are often mistaken for it. However, onions are high in FODMAPs, so you may want to avoid them on an IBS diet.

Zucchini and mushrooms are two other foods that are not nightshades, even though they are commonly thought to be.

Beware of hidden nightshade ingredients. Tomato and peppers are found in many foods and spices that you might not expect. Pay close attention to ingredient lists.

Nightshades & Autoimmune Conditions

Nightshades may contribute to autoimmune conditions, where your immune system mistakenly attacks your own body. Many factors can weaken your immune system or confuse it into attacking your own body. Autoimmunity can take many forms.

Here are examples of common autoimmune conditions frequently impacted by nightshades:

Leaky gut syndrome is a common root cause of autoimmune disease. Although the science is very early on this condition, some nutritionists and specialists posit that nightshades weaken your intestinal lining and may lead to a leaky gut, which triggers autoimmunity. 

The providers at PrimeHealth have helped our patients heal their leaky gut with BPC-157 (capsule or injectable form), which supports tissue repair by aiding in collagen production.

Nightshades & Inflammatory Bowel Disease

Nightshades may negatively influence inflammatory bowel disease (IBD) and your digestive tract as a whole.

According to an older study, both glycoalkaloids and solanine (the defining characteristics of nightshades) aggravate IBD, possibly even causing it in the first place. The study points out that IBD is most prevalent in nations that consume fried potatoes, such as French fries.

This 2021 study shows scientific evidence that adherence to an Autoimmune Protocol Diet, which eliminates nightshades among other foods, may improve autoimmune symptoms.

IBD used to be considered an autoimmune disease, but recent research suggests it may not always result from autoimmunity. However, IBD can definitely weaken your immune system.

Nightshades & Arthritis

Nightshades have been associated with arthritis. Although this causation is very uncommon in reality, nightshade foods are indeed associated with autoimmunity. Rheumatoid arthritis is an autoimmune disease.

Therefore, nightshades could inflame joint pain and arthritis in sensitive individuals.

Nightshades Allergy/Sensitivity

You may simply experience allergic reactions to nightshades but not autoimmunity. Children with asthma or other food allergies are at most risk of developing a nightshade food sensitivity.

A simple nightshade allergy may cause these symptoms:

  • Itchiness
  • Rash
  • Trouble breathing
  • Nasal congestion
  • Nausea

If you have a severe allergic reaction, you may need to contact your healthcare provider. If you have a lot of trouble breathing, call 911 right away.

How to Safely Consume Nightshades

To safely consume nightshades, you need to reduce the alkaloids and the lectins. I’ve separated my nightshade prep tips into alkaloid-reducing and lectin-reducing.

Nightshades contain small amounts of alkaloids, which may cause health problems if certain people consume them. Check out these ways to reduce alkaloid content in nightshade foods:

  • Cook them; don’t eat them raw.
  • Allow them to ripen because unripe nightshades contain more alkaloids.
  • Peel potatoes before cooking and eating.

Nightshades contain lectins, which may trigger autoimmune or inflammatory reactions. To reduce lectins, you can cook or prepare nightshade foods in the following ways:

Health Benefits of Nightshade Vegetables

The potential benefits of nightshade vegetables, fruits, and herbs depend on the food. Most nightshade foods are dense with nutrients, and many have anti-inflammatory properties.

Tomatoes are heart-healthy, great for your skin, and may even help prevent cancer. They are excellent sources of vitamin A, vitamin C, and the antioxidant lycopene.

Potatoes are a great source of vitamins, potassium, and fiber and contribute to antioxidant activity.

Many peppers contain capsaicin and are anti-inflammatory. They also increase metabolism, which can help fight obesity and prevent heart disease or diabetes.

Ashwagandha is a potent adaptogen that may contribute to a healthy reproductive system and immune system.

However, for those who are sensitive to nightshade foods, the risks probably outweigh these potential benefits.

Related: Adaptogens For Stress Management & Mental Wellness 

Substituting Nightshade Vegetables in Your Diet

You may want to substitute nightshades in your diet because you’re sensitive or because you want to be cautious. I’ve got some great tips for you to substitute nightshade vegetables, fruits, and herbs.

First of all, don’t feel like you really need to substitute these foods. Instead, try exploring new flavors. There’s no way you’ve tasted every yummy food on the planet. That said, below are some handy substitutes for the most common nightshade foods.

Common tomato substitutes include:

  • Chicken stock and vinegar
  • Olive paste
  • Cheese
  • Cucumbers covered with non-tomato-based hot sauce
  • Strawberries (especially on salads)
  • Tamarind paste

I love this “nomato” sauce recipe, which tries to capture that tomato sauce taste and mouthfeel without nightshade plants by using a lot of garlic and Italian seasoning.

Common potato substitutes include:

  • Turnips
  • Zucchini
  • Cauliflower
  • Celery root (celeriac)
  • Rutabaga
  • Daikon

The best non-nightshade herbs and spices include:

  • Garlic
  • Ginger
  • Salt and pepper
  • Oregano
  • Cinnamon
  • Cumin
  • Cilantro


Are blueberries a nightshade?

No, blueberries do not belong to the nightshade family. They are part of the Ericaceae family and are unrelated to nightshade plants like tomatoes and peppers.

Why should nightshades be avoided?

For some people, nightshades should be avoided due to the presence of alkaloids, such as solanine and capsaicin, which can cause sensitivities or autoimmune reactions. However, nightshades are generally safe and nutritious for the majority of individuals, and any avoidance should be based on specific health concerns or sensitivities.

What are the effects of nightshade foods?

The most relevant negative effect of nightshade foods is the inflammation triggered by the alkaloids within them. 

Are nightshades considered fruits or veggies?

Nightshades, as a plant family (Solanaceae), are generally flowering plants. This part of their reproductive process botanically classifies them as fruits. The term “vegetable” is often used in a culinary context rather than a botanical one. In the case of common nightshade vegetables, such as potatoes, bell peppers, and tomatoes, they are fruits from a botanical sense since they flower.

Do You Have to Give Up Nightshades Forever?

You may not have to give up delicious nightshades forever if you are able to address the root cause of your sensitivity. However, just as with any allergy, some people may be better off avoiding nightshades long term in order to live their healthiest life.

If you’re concerned about autoimmune diseases or dietary issues, we specialize in those areas. PrimeHealth is dedicated to helping Colorado residents like you with non-invasive, as-natural-as-possible treatments on an individualized basis.


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