The Pain Free Diet Blog

Plant-based, Paleo, probiotics, prebiotics, antibiotics, GMO, gluten-free, organic, all-natural, cleanses, detoxification, supplement, don’t supplement. Pretty confusing right? What is truly healthy and what is not? What is missing in the healthcare system that can treat your pain safely and effectively? Weekly articles explore trending topics, dig into the science, and debunk myths while giving you a sustainable approach to eliminate pain and improve your long-term health, function and vitality.


By: Jonathan Tait, D.O.

In a previous article I explained how cumulative dietary injuries can trigger chronic systemic inflammation that can rob you of performance and derail your recovery.

In Part 1 and Part 2 of Foods That Feed The Inflammatory Fire, I showed how the amount of sugar, fat type and content, essential fatty acid profile, and antioxidant score of foods is of critical importance.

Eating the correct foods can shift your body towards an anti-inflammatory state, improving performance and recovery.

Eating the wrong foods will have the opposite effect, promoting chronic systemic inflammation and pain.

Most people know about the toxic inflammatory foods  that can kick up inflammation in the body:

  • Refined foods chocked full of sugar, and trans fats
  • Grain-fed and processed meats
  • Gluten-containing grains
  • Soy
  • Dairy
  • Other chemicals laced throughout our food supply like artificial colorings, preservatives, artificial sweeteners, MSG, sulfites, pesticides and herbicides.

What about certain fruits and vegetables? Can they be even more inflammatory than the list above for susceptible individuals?

I’m not referring to GMO fruits and vegetables. That will be yet another discussion for another day.

I’m talking about nightshades. What are nightshades?

  • Vegetables – Potatoes, Eggplant, Tomatoes, Tomatillos, Hot and Sweet Peppers, Jalapeno Peppers, Pepino, Pimento
  • Fruits – Ground Cherries, Goji Berries, Huckleberry, Naranjillas
  • Spices – Paprika, Cayenne
  • Other – Tobacco
  • Not nightshades – Sweet Potatoes, Yams, Black Pepper

Nightshades are a group of over 2,800 plants – from the scientific order Polemoniales, and the Solanaceae families – that grow in the shade of night. Many of the nightshades species can be toxic when consumed by mammals.

The reason for this is that they naturally contain four different alkaloid compounds (steroid, tropane, pyrrolizidine, indole) produced as a natural protection mechanism, or pesticide, protecting the plant from being eaten by insects and animals.1

The alkaloids are most concentrated in the leaves, green varieties (tomatoes, peppers), and older potatoes.  You have probably experienced a bitter taste when eating potatoes. That is in large part due to the high alkaloid content.

The leaves also contain nicotine. Yes, the same nicotine as in tobacco, albeit in far less amounts.  Nicotine content is highest in eggplant and green tomatoes.

A few theories exist as to why these alkaloid compounds cause trouble:

  • Pro-inflammatory – An immune response is triggered in the gut that can contribute to systemic inflammation. That in turn can cause more joint pain in those already dealing with inflammatory joint pain.
  • Interfere with calcium metabolism – This can cause demineralization of bone as well as deposition of painful calcium deposits in soft tissues, and around joints.
  • Block an enzyme in nerve cells called cholinesterase.2 –  Cholinesterase inhibition can cause muscle twitching or even paralysis. Although the low levels found in nightshades are unlikely to cause this extreme effect, it is theorized that they may have a negative effect on optimal neuromuscular control.

Even if you are buying organic, if you are eating produce from this family of fruits, vegetables, and spices, this could be the reason your joints or muscles hurt, or your performance is tanking.

Well now you should have a fairly good idea about what foods could be potential pain triggers in your diet.

Next time I’m going to share what foods have the biggest potential to soothe your aching joints, help you recover, optimize your health and prevent chronic disease.



1.  Beier, R. C. Natural pesticides and bioactive components in foods. Rev Environ Contam Toxicol. 1990; 113:47-137.

2.  McGehee, D. S.; Krasowski, M. D.; Fung, D. L.; Wilson, B.; Gronert, G. A., and Moss,J. Cholinesterase inhibition by potato glycoalkaloids slows mivacurium metabolism.