Nightshades are everywhere

The word “nightshade” sure sounds ominous, huh? Did you read about the 9-year old girl who died from eating nightshades ? I have a feeling the answer is no, but please don’t worry too much. Plants that fall under the family of Nightshade (otherwise known by the fancy botanical name Solanacea ) are some of the most widely eaten foods on earth. Tomatoes and potatoes are the most commonly eaten of the edible nightshades, but there are a few others. Note what is not on the list: sweet potatoes, black pepper, and white pepper are not nightshades. Finally, note the most famous of all nightshades, and destroyer of lungs worldwide: the tobacco plant!


The man who started it all

Waaaaay back in the 1940s, a horticulturist named Norman Childers got the nightshade-pain ball rolling. He noticed that livestock who munched on nightshades had a tendency to develop arthritis. When these nightshade plants were taken away, the animals tended to have reduced arthritic symptoms. This phenomenon was noticed by others, namely veterinarians and botanists, but word didn’t really get out (Internet use was pretty low in the 1940s). More importantly, when Norman eliminated nightshades from his diet, his own arthritis was cured.  The specific reasons why nightshades might be implicated in some cases of arthritis will be explained later. But for now, consider a couple things about Dr. Childers.


A little note about plants

Don’t fall into this trap: “Tomatoes are vegetables. Vegetables are good for you.” First of all, you may be aware that the tomato is botanically a fruit, but legally a vegetable . Second of all, believing that edible plants are all good for you is a very modern way of thinking. Back in the day, before agriculture started, you had to know which plants helped you and which plants harmed you.  Nowadays, we all know which plants might hurt you, if you happen to be sensitive to them. The prototypical example is the ever increasing number of people with peanut allergies . But there are more bad plants than just the occasionally evil peanut and the occasionally trip-inducing mushroom. If you have a severe peanut allergy, you would know it because eating a peanut would lead to an anaphylactic shock and a trip to the ER. But there are many, many people who have reactions to plants that don’t happen right away, and hence are hard to tie directly to the plant. We will get into this in depth in future articles. One more note about these plants. Nightshades were not eaten by your ancestors. Is this important? Ehhhh… maybe yes maybe no.

Now that you know a little bit about nightshades, let’s learn a little bit about how they may affect pain by clicking on the next tab over …


Culprit #1…Vitamin D? 

Dr. Childers blamed the arthritis-inducing tendencies of nightshades on its vitamin D content. I bet you’re a little confused…isn’t vitamin D supposed to be good for you? In fact, the first paper I co-authored was on “Vitamin D and Cardiometabolic Outcomes” . Being entrenched in academia, I was skeptical of Dr. Childers’ claims. I’m still a little skeptical, but the science is pretty legit. Here’s why.

Way back in 1976, a professor of biomedical sciences at Cornell University got a paper published in the prestigious journal “Science”.  His lab found that a South American nightshade plant contained the active form of vitamin D! Other papers have backed up this finding. This is surprising. Too much vitamin D can potentially screw with your calcium balance. And because of the potent form of vitamin D in this plant, it can cause calcium to deposit into the joints of animals that eat the leaves, causing pain and crippling arthritis. Is this the case with humans? Nobody knows. The mechanism is there, but we don’t share the same physiology as these animals, nor do we graze on leaves in South America.  On the other hand, calcification is a big freaking deal. One of the best predictors of getting a heart attack is a high coronary calcium score. You don’t want calcium to be going where it doesn’t belong! If you are concerned about calcification, consider getting more vitamin K2 to help counter it, which is found in cheese, grass-fed butter, natto, and some supplements.


Culprit #2…Nightshades and your nervous system 

nervesYour nerves use certain chemicals to communicate with each other and with your brain. If something bad happens to this communication system, things can go wrong with many different things in your body. One of these chemicals is called acetylcholine, and certain chemicals in nightshades can screw up how acetylcholine gets used in the space between nerve endings.

How does this happen? Nightshades contain a variety of chemicals called glycoalkaloids, which are substances used by these plants to scare away animals that want to eat them. Pretty much like human-made pesticides, but naturally made. But natural is not always good! These natural pesticides, such as solanine and tomatine, can irritate your intestines and cause a variety of other problems by affecting acetylcholine. Thankfully, the majority of these substances are found in parts of the plant we don’t eat, such as the leaves. You don’t eat tomato leaves regularly, do you? Good.


Study #1: Arthritis, fibromyalgia, and the immune system

One study from 1998 looked at the relationship of food sensitivities to joint and muscle pain. It looked at how pain patients reacted to antigens from certain foods. What are antigens? Antigens are simply molecules that make your body mount an immune reaction.

The theory that this paper was based on is that antigens from some foods can leak through your intestine and cause joints and/or muscles to be attacked by your own immune system. Intestines can become leaky because of wide variety of things, including overuse of some medications and a diet high in gut-attacking foods. The authors found that between 56-67% of patients at their clinic who had pain issues were reactive to antigens from various nightshade plants. When patients were tested against antigens from several different foods, fibromyalgia patients had the highest rate of reactivity, followed by arthritic patients and then back pain patients. The study authors concluded that they found “a high correlation between food sensitivities and musculoskeletal disease”.

My take from this study: it doesn’t really mean anything, and is not a very high quality study because of poor study design, few patients, and lack of detail.  So while we may note with interest that there may be something to nightshade antigens and reactions in pain patients, we can’t really draw any conclusions from this paper.


Study #2: Dr. Childers’ report

Dr. Childers made it his mission to help those whose arthritis is caused by nightshades. As part of this effort, he surveyed volunteers to see if they had stopped eating nightshades and seen a decrease in pain. Most of the respondants (94 percent!!) were substantially helped by a nightshade-free diet, when they were rigid with following it. About two thirds had relief when mostly complying with the diet.

Unfortunately, this is another poor quality study. Dr. Childers did not make any claims as to the certainty of this data, which is good. Because this was simply a survey of volunteers who bought a book about nightshades and arthritis. One reason you might buy such a book is if you suspect that nightshades might be causing your pain. While you’re eliminating nighshades from your diet, you might do other things such as lose weight, or even just improve your symptoms from the time you started the book until the time you ended the book. So in summary, this is not a trial; and without a trial, it is hard to make any conclusions about the link between nighshades and pain in humans.


Should you think about eliminating nightshades?

So…are nightshades the cause of your pain? Probably not. But ten billion things can cause pain, so nothing is ALWAYS the culprit. The question is whether it is worth it for you to try an elimination diet. The answer is…definitely! Depending on who you are. No reliable lab test can predict if you are sensitive to nightshades. Those who are under high stress, have previously-injured joints, or have a genetic susceptibility to nerve issues should watch out. Here are some categories of people with pain, and my suggestions for them:


1. Longtime arthritis sufferer

Try a nightshade elimination diet. Just do it. It might do absolutely nothing, but you also don’t want to be taking pharmaceutical drugs with harmful side effects your whole life. Also, arthritis wears down joints over time, and you don’t want to be amongst the millions of Americans getting multiple replacement joints.


2. Sports injury

It might not be worth it. If you haven’t experienced pain before, and have an injury of moderate duration (a week to a couple months), the pain is probably not from nightshades.


3. Fibromyalgia

Try the diet! Not necessarily because nightshades are causing your pain, but because fibro is caused by so many strange things. But try to attack this from multiple angles–do some reading on fibro and massage, fibro and vitamin D, etc etc.


4. Autoimmune disease

Do you have an autoimmune disease? Then think about trying a nightshade elimination, getting your vitamin D level checked by your doctor, and eliminating wheat from your diet. There’s a lot of things to consider in autoimmune disease, and these are just some of them. But there’s no time like the present to become your own Sherlock Holmes, and potentially solve your own illness.


In conclusion, I’d say that nightshades are something that most people with chronic pain should at least learn about. Why? It costs exactly zero dollars to eliminate them, and I’m absolutely sure that at least a few people will be surprised at this seemingly innocent class of plants being the cause of their pain. But for everyone else who tries to eliminate nightshades and fails to see a decrease in pain, please keep your hopes up. There are many other things to consider related to pain, and we will cover most of them in the coming months.



  1. Great breakdown!  I’m glad you presented the evidence with the appropriate balance of reason and concern.

  2. So, the two studies you cited are the only studies ever done looking at a relationship between night shades and arthritis? That seems hard to believe since just about everybody is aware of this believe. I hope more studies are done.

    BTW, I enjoyed your writing style: very clear and not overly scientific

    • Yup, only two studies in humans, at least that I found over an hour or two of searching. There were a couple related animal studies, but you know, different physiologies and all. I don’t think studying nightshades and arthritis is a funding priority for Pfizer and Merck!

  3. Great blog!   I especially appreciate your analysis of the study design.  I like your writing style too- never thought I would chuckle reading an article about nightshades :)  Keep up the good work, look forward to hearing more.  – DJ

  4. Interesting… this makes me wonder if there may be a more evolutionary reason that I have an aversion to tomatoes and potatoes…

  5. I first heard about this connection in Annemarie Colbin’s book Food and Healing. It doesn’t affect me – my joints are stiff from too much sitting more than anything, but I wonder about my mother, who has had so many hip replacements. But she’s not the sort to try this sort of thing, and she really loves tomatoes and potatoes. (Sometimes we crave the things that make us sick.) :(

    • Nightshade elimination is one of the harder eliminations–which may be why so few people have done it and it hasn’t been studied much. I don’t know how much nightshades would contribute to something like hip degeneration, in comparison to some of the more common causes, but it could definitely exacerbate the pain.

  6. Hey Kamal you didn’t talk about the fact that saponins in nightshades upregulate lectins. Certain lectins cause intestinal permeability. I don’t know why you paint such a broad stroke here with it all.  Why not say hey take them out and see if you notice improvement depending on what you are eating with the nightshades. Maybe your genetics don’t like the combo of nightshades with _______.  If you still don’t notice any improvements then test them back in and see if you notice any issues. Do this over a long period because like you say it is hard to determine in a day or week the relationship or cause and effect. Sometimes the individual’s threshold will vary. I sort of like your website but I do think you are basing so much on published research and as I have found so much has yet to be researched in animals let alone humans. I think the real info is coming from individuals running their own in home labs without bias. I also challenge the idea that digesting vitamin D is a good option. Our ancestors didn’t digest it but were outside and got it that way for the most part. It is like saying we all need protein so lets eat lots of rice and beans. I think genetically there are many ways our genetics have adapted and all the more reason any studies are just snap shots of those individuals who were part of the study and by no means the final say on what works for my genetics. That is why a more broad approach to all of this is a better approach. I have moved on beyond Paleo and Cordain and his hanger oners  like Wolf and Sessions et al. They got an idea and then ran with it and it turns out the path splits up down the road into millions of paths. They have delayed this info much too long to keep the Paleo plates spinning in the air and it is a huge disservice to those with chronic health issues.

    • Interesting points, turnip. So what is ur nutritional philosophy if u “moved on beyond paleo and cordain”? Like u, I’m trying to decipher thru the nutritional muck

  7. This is a great summary with easy-to-follow logic! It encourages people to think for themselves, which I think is the best way to look at health issues. I might try reducing nightshades and see what happens.

  8. Kamal please see , and the links for these on the NIH site for relevant IgE mediated “allergy” responses.
    NB for patients suffering arthritis symptoms you’ll need to search “food intolerance”. Arthritis isn’t a widely accepted “allergy” response because the generally rapid onset and resolution of IgE responses isn’t an obvious fit with a chronic degeneratve condition. The NIH articles cited above have symptoms that conform to the “allergy” profile timeframe, but note that the 1st one is explicitly a non IgE response.

    • Interesting! I’ve heard of people who have mild allergic responses to tomatoes. Will have to do some digging into this area. If there’s more stuff, I’ll update the article. Thanks for the links.

  9. Thank you for your simple break down. Very well written. I did a full elimination diet for general health purposes this summer and was very surprised to find the tendinitis in my knees disappeared with the elimination of nightshades. I had never heard of this type of vegetable and had assumed the pain was an over use injury from years of playing soccer. I also had the added bonus of resolving my adult acne. Now I find that if I eat any night shade I break out the next day. If I eat nightshades two days in a row the pain in my knee returns. I do wish there were more studies done on the topic, mostly because my Italian family doesn’t want to accept a tomato intolerance…nor do many others want to believe.

  10. “Now that you know a little bit about nightshades, let’s learn a little
    bit about how they may affect pain by clicking on the next tab over …”

    Where would that tab be?


    • Right below the ratings box with the stars, there are four tabs called “Nightshades”, “Nightshades and pain”, etc. If you click on a tab, the information will come up. But now that you mention it (and a couple others have as well), the tab system kinda sucks, so I’ll switch it to regular text or a more logical system soon. Thanks!

      • Thank you. I saw that after I posted (smacks head) which is why I deleted the comment. I went to a couple of seminars on how to forage for plants in the wild. What a difficult and potentially dangerous task. Hemlock grows everywhere and by late spring many plants have become stringy and tough.

        The course in wild foods lead me to the conclusion that farmers are wonderful. Domestication really does take the edge off of nature. I have never seen a tomato in the wild. I wonder if they are safe to eat.

  11. I had fibromyalgia since childhood. I went on the guaifenesen protocol seven years ago and got my life back. The brain fog, irritable bowel and bladder, depression and pain went away. Then about 3 years after being on the protocol the nerve pain started, mostly with my back them eventually spread to my whole body. Turns out I am intolerant to nightshades, gluten. They cause debilitating pain for me.

    • Awesome! I tried guaifenesen even though I don’t have fibro and…no dice. But worth a try.

  12. Hello! I’m wondering if you personally have tried the nightshade-free diet, and if it helped your pain. I ask because my condition is the same as yours– Ehlers-Danlos. It’s been driving me crazy trying to see whether there’s a correlation between nightshade consumption and pain. There have been many times I’ve eaten a spicy meal and had a bad pain reaction afterwards, which makes me want to avoid these foods, but then I’ll eat other foods that certainly do not have nightshades, and have a pain reaction too, so it’s hard to pinpoint. Anyway, would love to hear your thoughts/personal experience regarding EDS and nightshades. Thanks!


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