Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
12 Jun


NightshadesAs you (our gracious company of Apples) know, we unequivocally love our vegetables. Powerhouses of nutrients and antioxidant action, they’re the backbone of a good Primal Blueprint diet. But the issue of nightshades has come up a few times recently. Nightshades, those vegetables that find their roots in the Solanaceae family of plants, include a host of reputable veggies and spices: eggplant, potatoes (yes, we know, not so reputable), peppers, tomatoes, tomatillos, pimentos, paprika, cayenne pepper, Tabasco sauce, et al. (Black pepper isn’t included in this list.)

Nightshade, you might exclaim? Isn’t nightshade those plants (many with alluring little berries) our camp counselors told us never, ever, to so much as put our grubby hands on? Quite possibly. The kinds of nightshade plants growing wild in the woods can be highly toxic. Some can cause death if ingested. Some actually have psychotropic properties. Inherent in this power is pharmaceutical potential. Very minute amounts of some nightshade components are prescribed to successfully treat a few kinds of allergic reactions or chemical poisoning as well as nausea related to certain conditions.

These potent little components are alkaloids, chemical substances that have one or more circular structures containing nitrogen. Essentially, they act as natural pesticides. (Evolution wasn’t just our gig after all. A plant’s gotta protect itself!) Four kinds of alkaloids in the Solanaceae family include the steroid alkaloids (the alkaloid found in most nightshade foods), tropane, pyrrolizidine and indole alkaloids. Steroid alkaloids have been shown to block certain nerve activity that can, at high levels, cause muscle shaking, paralysis and respiratory difficulty. They have also been associated with inflammation, particularly in the joints. Finally, some nightshade foods like eggplant and tomato contain trace amounts of nicotine.

But what does this mean for the tomato salad I always serve at our 4th of July barbeque? Should I give up eggplant parmigiana? No peppers or Tabasco? I thought hot food was good for me!

Before you raid your kitchen and gardens, let’s stop and take a closer look here. First off, nightshade foods contain a very small fraction of the alkaloid levels found in other “toxic” nightshade plants. If nightshades presented a major health threat to humans, we would’ve stopped eating them a long time ago or died off from the inability to learn from our neighbor’s experience. Even when nightshade foods are common ingredients in certain ethnic diets (peppers in parts of Latin America or tomatoes in Italy, to give some basic examples), the population as a whole in those parts doesn’t seem to suffer ill effects.

So, what gives? Are they bad, or are they O.K.? Our simple answer: eat them (and enjoy them) in moderation if you don’t feel any ill effects. While research hasn’t yet turned up any definitive evidence that the alkaloid-containing foods in question harm the human system, it’s generally accepted that some people are much more sensitive to them than others. Nightshades, in those with this sensitivity, have been associated with symptoms like stomach discomfort, digestive difficulties, joint pain, and muscle tremors. These reports have been enough to influence medical care professionals and some organizations to advise those with certain conditions like GERD, gout, or arthritis to avoid nightshades. If you don’t have these conditions but are concerned, it’s a good idea to take a full 2-4 weeks off from nightshade foods and see if you feel any differently. Some of us have mild enough reactions that we may not feel the difference until we set our own “control” scenario for comparison.

Finally, if sensitivity doesn’t seem to be a problem but you’d like to take some reasonable precautions, know that cooking nightshade foods (steaming, boiling, baking) can reduce the alkaloid levels to nearly half. And yet another reason to avoid potatoes: sprouted potatoes (and their associated green parts) have higher levels of alkaloids than other foods.

And, finally, we’d like to put in a plug for a widely varied diet. As much as we love our tomatoes, eggplants, and peppers, we wouldn’t recommend making them the sole or primary vegetables in your diet. Variety offers the best in nutrient-rich and low-risk nourishment.

What are your thoughts on nightshades? Do you choose to embrace or avoid them? What influences your decision?

willsfca Flickr Photo (CC)

Further Reading:

Smart Fuel: Eggplant

Flame Thrower: 10 Ways to Reduce Inflammation

Health Benefits of Peppers (10 Peppers You Need to Try)

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You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. When I quit nightshades, it was like a miracle! I have eliminated almost all of the joint aches, tendonitis and reflux. Still struggling with food options since I don’t really like the flavor or texture of most fruits and vegetables.

    Gluten is next as it impacts your body’s absorption of Vitamin D and calcium when you are sensitive, often not diagnosed other than low D in a blood test.

    Isabel wrote on March 6th, 2012
  2. Nighshades are potentially the sneakiest cause of joint pain–gluten can cause joint pain through leaky guts, but nighshade effects tend to come on quicker. I run a website all about pain, and just wrote up an article about the evidence for and against nightshades and pain. Check it out at!

    Kamal Patel wrote on March 10th, 2012
  3. I have been nightshade free for three years and the difference is amazing. I no longer have the episodic knee and joint pain, but also the general stiffness that I had just accepted as normal went away as well. Also, most of my mother’s family thought they suffered from arthritis, but for those that have implemented a nightshade-free diet, this has completely went away.

    Although, I do have to note on your post that it generally takes longer than 2-4 weeks to see a difference. Most research says to try it for 6 months. I didn’t see the full result until 4-5 months into a nightshade-free diet – so don’t give up if you don’t think it works after a few weeks.

    Mckenzie wrote on June 27th, 2012
  4. Unfortunately for me, nightshades cause eczema on my hands and eyelids. And they also create a dazed and confused condition that I believe is another symptom of this allergy. It is as if the eczema is the visible sign of neurologic distress in my body (who knows what’s going on inside where you can’t see). An allergist discovered this when I was a child and we did a food restriction diet and my eczema went away. It was just tomatoes in the beginning, but now that I’m in my 60s, I get the symptoms when I eat any nightshade. So, bottom line…Eczema sufferers, try dropping the nightshades!

    Erin wrote on June 27th, 2012
  5. I have a skin condition called Hidradenitis suppurativa. It’s extremely painful and very difficult to treat. I have never heard of anyone successfully putting it into remission until I read about a woman named Tara (aka Primal Girl) in one of Mark’s books. I googled here and read her story about putting her HS into remission here ( Never been so excited to read a blog post in my life! I was already cutting back on nightshades as I felt they were impacting my digestion, but I finally gave them up completely once I read Tara’s story. I was flare-up free for a couple weeks, then “tested” a myself, eating peppers, and had a flare up within 24 hours.

    Chris wrote on August 13th, 2012
  6. Hi What are the night shade veg. I know Tomatoes are one. thanks

    julie wrote on February 16th, 2013
  7. Just revisited this post.. Might be worth noting Goji berries are included in the nightshade family also.

    Phill T wrote on March 1st, 2013
  8. My six-year-old daughter has had stomach pains and diarrhea since she first started eating solid foods. At first, we took gluten and dairy out of her diet, but that only cleared up the diarrhea, not the pain. The doctors tried several types of medications, and scoped her stomach. She had open sores in her stomach, but they couldn’t find a reason for them. About two months ago, I read this article on nightshades (as well as one from and decided to try removing them from her diet. Her stomach pain is completely gone now. I’m hoping to get another scope done this summer to see if the sores have also healed.

    Celeste wrote on May 24th, 2013
  9. I recently ate too many potatoes and every joint in my body had become inflamed. My Holistic Practitioner confirmed I have an intolerance for nightshade. I have totally cut out nightshades from my diet and did a 3 day water fast which resulted in great improvement. It has been about 3 weeks and I still have some inflammation and discomfort in my elbows, knees and hips. I am very healthy and eat mostly raw and organic or all natural foods. I had no joint issues before the potato episode. Does anyone know of a cleanse to remove all the alkaloids? I tried googling but can’t find anything.

    JC wrote on May 31st, 2013
  10. I pretty much only eat what I can grow- tomatoes, peppers, eggplants. All organic and mostly cooked. I rarely ever buy those in the store. No problems! I make amazing tomato based dishes with eggs, middle eastern. Wonderful!

    nancy wrote on August 2nd, 2013
  11. I just want to add that golden berries also known as gooseberries and inka berries which have been touted as being anti-inflammatory also are in the nightshade family which can actually be pro-inflammatory to sensitive people. They are in the family of physalis of which all are night shades.

    Dan wrote on January 15th, 2014
  12. I have a nightshade allergy, it backs up my system, and is very painful. I miss tomates and potatoes sooo so much!!!

    Amanda wrote on January 30th, 2014
  13. My husband has had joint pain since his early 20’s… he’s now 44. Years ago someone mentioned nightshades as a possible reason for them, but we were young and found it too hard to give up potatoes and tomatoes….. About four years ago we did, along with sugar, and the lessening of his joint pains has been amazing! Sometimes we fall off the wagon, but by and large if he stays away from these things, he is pain free. Unfortunately, I have no ill effects from these things but now can’t have them either! Sa la vie…. all in the name of love xx

    Tyler wrote on June 2nd, 2014
  14. I think I may have found the answer. FIVE YEARS of joint pain, muscle aches, head aches, shoot pains through my bones, horrible fatigue, headaches, digestive issues.

    I am 23. I limp everywhere. My friend mock me with the Cards Against Humanity card: Moderate to Severe Joint Pain. It’s my card.

    I did a three day fast and broke into Primal a week ago. My joint pain dropped by 80%. Then I made a spicy salad with chipolte dressing and my pain was up again. Figured out the connection. Finally. I have literally looked into everything. This explains so much. Sensitivity to cigarette smoke. My poor teeth (Granted, sugar and grains weren’t helping). Why Taco Bell or Pizza were the worst.

    Why my pain stopped for little while when I did Gluten Free…Because I was cooking Asian everything with no peppers.

    This is…amazing. But also frustrating. I love my spices….

    Thank you for addressing this with the community.

    Jade wrote on June 4th, 2014
  15. I recently discovered that I’m allergic to nightshades. In researching them, I learned that the popular supplement, ashwagandha, is a nightshade. It was in a compound that I took every day.

    Judy Barnes Baker wrote on June 10th, 2014
  16. Ive got IBS so there’s a lot of vegies I cant eat. I really rely on eggplant, tomatoes and capsicum (peppers in America?) to add flavour to my diet and variety. I eat them everyday…could this cause some kind of long term damage? :/

    Anzju wrote on May 26th, 2015

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