09/04/2026
Imagine this: someone with rheumatoid arthritis says, “Every time I eat pizza, fries, or tomato sauce, my joints feel worse the next day.”
It’s easy to blame tomatoes or potatoes immediately. But the science is more nuanced.
Tomatoes, white potatoes, peppers, and eggplant belong to the nightshade family (Solanaceae). These foods naturally contain plant alkaloids, including solanine and related compounds. That’s where the concern about inflammation comes from.
But here’s the important part:
Current research does NOT show that nightshade vegetables universally cause inflammation or arthritis flares. In fact, tomatoes, peppers, and eggplant also contain fiber, vitamins, antioxidants, and other compounds that can be part of an anti-inflammatory diet. The Arthritis Foundation specifically notes that there isn’t solid scientific evidence proving nightshades trigger arthritis pain in everyone.
So why do some people swear they feel worse after eating them?
Because individual responses can be very different.
For someone living with rheumatoid arthritis, psoriatic arthritis, chronic joint pain, or digestive inflammation, certain foods may genuinely seem to coincide with more stiffness, swelling, bloating, or pain. Researchers are still studying the relationship between the gut, immune system, inflammation, and joint symptoms.
The foods people usually mean by “nightshades” include:
🍅 Tomatoes and tomato sauces
🫑 Bell peppers and chili peppers
🥔 White, yellow, red and russet potatoes
🍆 Eggplant
🌶️ Paprika and some pepper-based spices
Sweet potatoes are not nightshades.
And one useful safety note: green or heavily sprouted potatoes can contain much higher concentrations of glycoalkaloids and should be avoided.
So should you cut all of these foods out?
Usually, no — not automatically.
A better approach is to treat your body like an experiment.
If you repeatedly notice more joint pain after nightshades, try removing the whole group for about 2–3 weeks while keeping the rest of your diet relatively stable. Keep a simple symptom diary: morning stiffness, pain, swelling, digestion, energy.
Then reintroduce them one at a time.
For example:
Week 1: add tomatoes back.
A few days later: try peppers.
Then potatoes.
Then eggplant.
If symptoms clearly return every time you reintroduce one particular food, that information is far more useful than eliminating an entire nutritious food family forever based on a general rule. This elimination-and-reintroduction approach is also suggested by arthritis-focused health organizations.
And don’t forget the bigger picture.
If your “tomatoes” are usually on pizza, your “potatoes” are usually French fries, and your “peppers” are in highly processed meals, the problem may not be the nightshade at all. Overall dietary pattern, excess calories, saturated fat, refined carbohydrates, sleep, stress, gut health, weight, medications, and disease activity can all affect how you feel.
The goal isn’t to fear food. It’s to learn which foods work for your body.
If you live with rheumatoid arthritis or chronic joint pain and you’re constantly trying to figure out what’s triggering your symptoms, talk with your physician, dietitian, or pharmacist before making a very restrictive diet.
💚 Ask Omar the Pharmacist at Welltopia Pharmacy about supplements, medications, nutrient deficiencies, and other factors that may be contributing to inflammation or joint symptoms.
📞 262-429-9429
🌐 welltopiarx.com
