This is a great question!
The nightshade, or Solanaceae family, is a truly fascinating one. It is comprised of over 3000 different species, including several common food plants, such as tomatoes, potatoes, eggplants, and all peppers in the Capsicum genus (sweet/bell peppers, hot peppers, paprika). The Solanaceae family also contains some potent alkaloid-rich plants, such as tobacco (Nicotiana tabacum) and Hyoscyamus, from which the drug hyoscyamine is extracted.
Not many folks know that two very common medicinal plants, Ashwagandha and Goji berry, are also nightshades. These are now widely distributed in protein powders, vitamins, teas, superfoods and herbal blends. While decidedly medicinal, both of these herbs are also considered generally safe and “food-like.” However, sensitivity to nightshades as a family is not uncommon, and can present in a few different ways. This is not necessarily a “true” allergy, ie, you might not register as allergic to these substances in standard IgE allergy testing, but rather an inflammatory response to certain components found throughout the nightshade family.
In my practice I have seen two main presentations of nightshade sensitivity: gastrointestinal (GI) disturbance, and joint inflammation.
In cases of GI disturbance from nightshade intolerance, I mainly see reflux, stomach pain, and IBS exacerbations.
Joint pain from nightshades can be distributed throughout the body, to joints already affected by osteoarthritis or inflammation, or targeted to a single joint or area (such as the right hand).
One might also see skin rash, rosacea flares, or exacerbations of other “heat” signs such as eye redness, lip dryness, irritability.
When a client comes to me with these symptoms, particularly the combination of reflux or joint pain, I nearly always recommend starting with an elimination diet that includes nightshade restriction. We comb through their supplements, protein powders and smoothie additives to make sure there is no Ashwagandha or
Goji hiding out; this way, the elimination is complete. Nightshades are treated as a reintroduction after 3-6 weeks (or more) of eating a simple, anti-inflammatory diet.
Sometimes a client is sensitive or reactive to all nightshades; other times, only some nightshades trigger symptoms. If you have improved with the removal of all nightshades, it is worth re-introducing them one by one to see if there are certain that you tolerate. For example, you may tolerate potatoes, eggplant, and Ashwagandha, but react to tomatoes and peppers.
In cases of more pronounced nightshade sensitivity, even the minute amounts of Ashwagandha found in say, a women’s food-based multivitamin, could trigger symptoms. Every one of us is truly unique, with our own set of genetic and environmental influences on health. An anti-inflammatory elimination diet can go a long way in finding out your ideal food supply. I have written an information-packed guide that is full of elimination-diet approved recipes—you can download it here
Lily Mazzarella, MS,
CNS has been a practicing Clinical Herbalist and board-certified Nutrition Specialist for over 10 years. She is owner and lead practitioner at Farmacopia
, an integrative clinic and herbal apothecary in Santa Rosa, California.
Lily’s practice is informed by scientific study, traditional constitutional systems, attention to the latest research, and an intimate knowledge of the “character” of hundreds of herbs, foods and nutrients.
She began her herbal education at Northeast School of Botanical Medicine in Ithaca, and went on to receive her Masters of Science in Herbal Medicine from Maryland University of Integrative Health.