As someone who works closely with clients navigating thyroid and autoimmune conditions, I’ve seen firsthand how nutrition can play a powerful role in healing—or in aggravating symptoms. One group of foods that often comes up in these conversations is nightshades.
What Are Nightshades?
Nightshades are part of the Solanaceae family and include familiar foods like:
- Tomatoes
- White potatoes
- Peppers (bell, chili, cayenne, paprika)
- Eggplant
- Goji berries
- Tomatillos
- Ashwagandha (a popular adaptogenic herb)
While nutrient-dense for many people, these foods can cause issues in those with autoimmune conditions—especially Hashimoto’s Thyroiditis and Graves’ Disease.
The Inflammatory Side of Nightshades
Nightshades contain natural plant compounds that may provoke inflammation in sensitive individuals:
- Lectins, which may damage the gut lining and increase permeability
- Glycoalkaloids, like solanine and tomatine, which may interfere with gut health and nerve function
- Capsaicin, which can trigger acute inflammation in some people
For individuals with autoimmune conditions, a compromised gut barrier (“leaky gut”) often precedes immune dysregulation. Several studies highlight how compounds in nightshades may exacerbate this process.
Source – Frontiers in Immunology
Source – NIH Glycoalkaloids
So… What About Nicotine?
Here’s where it gets interesting. Nightshades also contain trace amounts of nicotine, especially tomatoes and eggplants. Nicotine is often associated with smoking, but in small amounts from food, it behaves differently.
Some studies suggest that nicotine may have anti-inflammatory effects, particularly by modulating the immune system via the cholinergic anti-inflammatory pathway. For example, it’s been explored for its ability to reduce inflammation in conditions like ulcerative colitis.
Source – Nature Reviews Immunology
So should we see nicotine in nightshades as a good thing?
Possibly—but not universally. While trace dietary nicotine may benefit some, it doesn’t outweigh the potential downsides for those already struggling with inflammation, autoimmune issues, or gut dysfunction. Most of the nicotine research showing benefit is done under controlled settings, often with pharmaceutical-grade nicotine—not via nightshade foods.
How to Know if Nightshades Affect You
Not everyone with thyroid or autoimmune issues reacts to nightshades. But if you’re experiencing:
- Joint or muscle pain
- Skin rashes or acne
- Acid reflux
- Brain fog or fatigue
…it might be worth eliminating nightshades for 30 days to see if symptoms improve.
Then, slowly reintroduce them—one at a time—over three days each. Track your body’s response closely.
What About Ashwagandha?
Ashwagandha is a nightshade that I’ve often recommended for stress and thyroid support. Most of my clients tolerate it well, but if you’re following a strict autoimmune protocol and still have unexplained symptoms, it may be worth taking a short break from it to test your response.
Final Thoughts
The idea that “healthy” foods can still be harmful to some people is a powerful reminder that bio-individuality matters. While nightshades offer nutrients and even small amounts of beneficial compounds like nicotine, for those with autoimmune thyroid conditions, the inflammatory potential often outweighs the benefit.
If you suspect nightshades may be contributing to your symptoms, try a short elimination. It’s a simple, effective way to listen to your body and make empowered decisions around your healing.
References:
- Frontiers in Immunology – Lectins and Autoimmunity
https://www.frontiersin.org/articles/10.3389/fimmu.2017.00598/full - NIH – Glycoalkaloid Toxicity Review
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7770496/ - Nature Reviews Immunology – The Cholinergic Anti-inflammatory Pathway
https://www.nature.com/articles/nri1348 - Dr. Loren Cordain – Nightshades and Autoimmunity
https://thepaleodiet.com/wp-content/uploads/2019/03/AutoimmunityNightshade.pdf
