Killer Tomatoes and Poisonous Potatoes?

Remember the movie “Attack of the Killer Tomatoes”?  That was fiction, but some alarmists would have us believe that the tomatoes and potatoes on our plates are really out to get us.

I recently got an e-mail inquiry from an MD who said he had read that solanine in tomatoes, potatoes, and eggplants could be responsible for essential hypertension and a number of GI complaints, as well as symptoms of rheumatoid arthritis, apparently through their inhibition of acetylcholinesterase. He had looked for supporting scientific studies and hadn’t found any. He wondered if I had seen any such studies. I looked too. I couldn’t find any either.


Tomatoes originated in the New World. They suffered from guilt by association because they were related to the deadly nightshade. Early on, they were used for witchcraft and as an aphrodisiac (“love apples”). They were slow to gain acceptance in Europe and the US, not coming into common use until the early 1800s. Thank goodness they finally did: without them, Italian food just wouldn’t be the same. Potatoes, another import from the New World, were also suspect: they were even accused of causing leprosy. Tomatoes are technically a fruit, although they are generally classified as a vegetable. Remember the attempt to count ketchup as a serving of vegetables in school lunches?

Solanine Poisoning Is Real

Solanine is indeed a poison in large doses, causing everything from gastrointestinal symptoms to hallucinations, paralysis and death. Large amounts are toxic, but the amounts usually found in food are innocuous. It is poorly absorbed and rapidly excreted. It is estimated that it would take 2–5mg per kilogram of body weight to produce toxic symptoms. A large potato weighs about 300g and has a solanine content of less than 0.2mg/gm That works out to around 0.03mg per kilogram for an adult, a hundredth of the toxic dose; I figure a murderous wife would have to feed something like 67 large potatoes to her husband in a single meal to poison him. Unless he’s a phenomenally big eater, arsenic would be a better bet. Potatoes that are diseased with blight or that have sprouted have a larger than usual amount of solanine. They will have a bitter taste and often a green discoloration; such potatoes should be avoided. Even integrative health guru Andrew Weil is not afraid of solanine, pointing out that there hasn’t been a single case of solanine poisoning in the US from eating potatoes in the last 50 years.

Solanine Toxicity Syndrome Isn’t

I found information about “Solanine Toxicity Syndrome” on the website of a chiropractor who uses bogus muscle testing (AK) to diagnose it. He finds that almost all arthritic patients test positive. He claims that in sensitive patients, solanine can:

  • act as an endocrine disruptor especially to the thyroid
  • cause chronic joint pain, arthritis (all forms), joint inflammation- this is due to solanines ability to remove calcium from the bones and deposit it in any weak or genetically predisposed area of the body
  • for the same reason it can be a major contributor to osteoporosis (since it removes calcium from the bones) and arteriosclerosis (it can deposit the calcium in the blood vessels)
  • “leaky gut” as well as IBS
  • appendicitis
  • birth defects including spina bifida
  • depression (correcting it in one patient stopped their strong suicidal tendencies)
  • migraines
  • greatly interfere with calcium and vitamin D absorption, despite supplementation

Scientific Evidence

This will be a very short section. He doesn’t provide references. I looked for credible published evidence to support these claims. I couldn’t find a thing.

Testimonial “Evidence”

He describes his moment of epiphany. While he was treating one of his chiropractic patients, he happened to mention that he had been having pain, stiffness, and swelling in his hands, especially in the mornings (symptoms suggestive of rheumatoid arthritis). The patient asked him if he had eaten eggplant parmesan last night. He had! There you go! That must mean that dietary solanine is hazardous to your health, right?  For someone who believes in AK, that was easy enough to believe. Practice makes perfect: the White Queen in Through the Looking Glass practiced believing as many as six impossible things before breakfast. Believers don’t need no stinkin’ science.

There are a number of testimonials in various places on the Internet from individuals who claim to be unusually “sensitive” to solanine, but no controlled studies to support such claims.

Should We Avoid All These Foods?

Solanine-containing foods from the nightshade family include:

  • potatoes
  • tomatoes
  • paprika
  • eggplant
  • peppers

Foods that are not part of the nightshade family but that also contain solanine include:

  • Blueberries
  • Apples
  • Cherries
  • Sugar beets
  • Huckleberries
  • Okra
  • Artichokes

All these foods can be part of a healthy diet. Their solanine content is not a concern. It’s hard enough to get people to eat their vegetables without this kind of irresponsible fear-mongering.

Bottom line: Avoid green potatoes; otherwise, no worries!

Posted in: Energy Medicine, Nutrition

Leave a Comment (41) ↓

41 thoughts on “Killer Tomatoes and Poisonous Potatoes?

  1. BillyJoe says:

    Hmmm….fried tomatoes and egg on toast (:

  2. bug_girl says:

    Actually, there is a more recent case of mass potato poisoning–1979.

    Overall, though, agree: don’t eat green potatoes. I’ve seen them in health food stores sold as “extra healthy”. Sigh.

  3. Oh, wow. That is funny! You really gotta love chiropractors. They just make crap up and start “treating” it.

    List of chiropractic invented non-existant diseases:
    – Subluxations
    – Solanine Toxicity Syndrome
    – Ileocecal Valve Syndrome
    – Intestinal Candidiasis
    – Adrenal Fatigue

  4. Sorry to double-comment. Look at this “story” from that chiropractor’s website:

    He clearly has almost no understanding of physiology or pathology. (“My adrenals give out in the fall.”) He honestly has the same understanding of the human body as a child. And this is a licensed “doctor.” That is, in a word, scary.


  5. Angora Rabbit says:

    I’ve long suspected there was something wrong about okra…

  6. WilliamLawrenceUtridge says:

    “Fruit” is a scientific category, “vegetable” is a culinary, and thus arbitrary one. One of my favourite facts.

  7. Scott says:

    There are also (at least historical) legal implications to fruit/vegetable classification. The typical example is Nix v. Hedden, wherein the classification as fruit or vegetable determined the tariff to be applied to imported tomatoes.

  8. Calli Arcale says:

    I’d prefer to say that tomatoes are vegetables, and so are things like apples, because they’re all vegetable matter — that is, they are parts of plants. :-D It’s fair to define a tomato as a vegetable; peppers are usually considered vegetables, and they’re also a type of berry, so obviously this has more to do with the dishes usually prepared from them than anything else. (Though if we considered tomato a fruit, would it change how we serve it? Would we see less use of tomato in savory dishes, and more use of it in sweet dishes, especially desserts?)

    Potato poisoning is probably more commonplace than is reported; mild cases likely wouldn’t trigger medical attention. Frying potatoes destroys much of it. They tend to taste bad if they’re growing more solanine, so one wouldn’t be inclined to eat enough to get sick unless one was short of food or just really stubborn. :-D It helps that domestic varieties have been bred for flavor; this has reduced the amount of solanine in them.

    I’m not sure tomatoes actually contain significant amounts of solanine.

  9. I’m confident that eating 67 potatoes would kill me, regardless of the solanine. :-)

  10. Actually, there is a more recent case of mass potato poisoning–1979.

    But, just to be nitpicky, it wasn’t in the U.S. :-)

  11. Dawn says:

    @SkepticalHealth: I’ve seen people with pulmonary embolisms. 1 lived, one died. I find it VERY hard to believe this man had ” …had at least 8 large embolisms effecting every lobe of the lungs and the hospital physician said considering their size and the average rate of growth of untreated ones, if they hadn’t found them I probably would have died within the next three days.” And this man is an actual, licensed DC? Where on earth did he learn ANY anatomy/physiology? And I’d promptly kick the “hospital physician” out of any practice he/she/it had. Why does this whole story sound VERY suspicious? Pneumonia I can buy. It will show up on X-rays in various lobes. But P.E.s? 8+? I really don’t buy that. I’m not a MD, and would be really happy for any of the MDs on here to tell me it can actually happen this way. But until then…nope.

    And I love just about everything on the “do not eat it will kill you with solanine” list. Okra – meh. It’s OK, I’ll eat it but won’t go out of my way to get it. Any of the others…I’ll happily eat. But I really doubt I could eat enough to kill me…..

  12. Roadstergal says:

    Eggplant, tomatoes, okra, and artichokes? How am I not dead already? :D

  13. mousethatroared says:

    Interesting article, HH. I hadn’t heard of that one. We have a lot of nightshade that crops up around our yard. Unlike potatoes, the resemblance of tomatoes to nightshade is quite obvious. I occasionally wonder who was the brave (or really hungry) soul that decided to brave tomatoes, knowing about nightshade. Glad they did, nothing like fresh garden tomatoes. Although BillyJoe gave me a craving for some fried green tomatoes and I won’t see those for months.

  14. Janet Camp says:

    If you keep your potatoes in a dark place (cupboard is fine–need not be a root cellar!) they won’t turn green. It’s light that activates the solanine as I understand it.

    Okra is the one veggie I will not eat–except in curry for some reason. The Indians seem to know how to keep it from becoming totally slimy!

  15. cervantes says:

    The foliage of tomatoes and potatoes is toxic, however. But also not something anyone would eat.

  16. Geekoid says:

    There are no ‘Vegetables. Its a catch all from “Vegetation’
    So, all plants are vegetables.
    All plant also have finer classifications. Legume, Nut, fruit, bean, etc…

    When used as a noun, it means the edible part of the plant.
    The confusion isn’t whether or not it’s a fruit, it stems(HA!) from trying to put specific plants onto a more ‘legitimate’ pedestal.

  17. rmgw says:

    “Eggplant, tomatoes, okra, and artichokes?”…well, we don’t see okra very much, but – good grief! That’s the Mediterranean diet down the chute!

  18. CC says:

    # Calli Arcaleon

    (Though if we considered tomato a fruit, would it change how we serve it? Would we see less use of tomato in savory dishes, and more use of it in sweet dishes, especially desserts?)

    Ok, now I have to find a recipe where tomato is used the way a fruit would be. And if I can’t find one, I’ll have to make one. Oranges are also acidic and they’re fruits. This has to be possible.

  19. Louise says:

    This is really interesting because I just wrote a paper about this exact issue. I’m a 4th year Toxicology major and in my applied tox class we had to discuss this. I don’t think that the toxin in tomatoes is solanine. All the research that I did and that my tox prof marked as correct show that the toxin in tomatoes is tomatine not solanine. Tomatine is a related glykoalkaloid however it is not as well absorbed as solanine so it is even less dangerous. In my class discussions, we came to the conclusion that if a small child ate a moderate number of the leaves of the plant, they may show some symptoms of tomatine toxicity. Red tomatoes are no problem because the tomatine disappears as the tomatoes ripen. There is a huge lack of research though. Solanine is well studied but tomatine isn’t.

  20. lilady says:

    I just don’t “get” the affection for okra. To me, it looks and tastes like an icky substance.

    I devour tons of tomatoes when they are in season…with basil, fresh ground pepper and drizzled olive oil.

    Does Campbell’s Tomato Soup cake qualify as a dessert made from tomatoes?

  21. CC says:

    Dunno, it said at the end that the tomato qualities disappeared and it was a spice cake. Which is good, but isn’t tomato-as-fruit. I’ve had chocolate beet cake, and it’s also wonderful, but you don’t taste beets in it.

  22. kathy says:

    Botanically speaking, a fruit is anything that contains seed. The plant produces it to protect and disperse the seeds. It can be juicy like a tomato or dry like dry bean pods or spiny/hairy/sticky – the number of variations is many and fascinating if you are into botany.

    Culinarily (is this a word?) the definition of fruit vs vegetable isn’t consistent or logical – it’s mainly a matter of custom. For instance a pumpkin is a fruit botanically but in cooking it’s a vegetable; same for green beans but not for dry beans, or for peas, which are seeds. And many of the grasses are fruits, e.g. wheat, oats, unpolished rice, etc., though they look like seeds (until you dissect them that is).

    It isn’t a matter of the taste either that decides it – sweet oranges are fruits but so are bitter grapefruit (pomelos) and sour lemons.

    Underground storage organs like potatoes, yams and carrots, are always called “vegetables” not fruits.

  23. @lilady, oh, you haven’t lived until you’ve had deep fried okra :)

  24. Scott says:

    @ lilady:

    Campbell’s Tomato Soup barely qualifies as made from tomatoes to begin with, so the cake certainly wouldn’t…

  25. Calli Arcale says:


    Ok, now I have to find a recipe where tomato is used the way a fruit would be. And if I can’t find one, I’ll have to make one. Oranges are also acidic and they’re fruits. This has to be possible.

    Well, salsa is pretty darned close to a fruit compote….


    Culinarily (is this a word?) the definition of fruit vs vegetable isn’t consistent or logical – it’s mainly a matter of custom.

    Yep; and what one country puts in sweet dishes, another may put in savory dishes, and vice versa. Asian cuisine can be quite surprising to people who grew up on European cuisine for this reason.

    The case of the tomato as a vegetable actually goes back over a century, and the stakes were high at that point — it wasn’t just about health, it was about *money*. ;-) A new tax had been introduced, which applied a tarriff to imported fruits. So whether the tomato was a fruit or a vegetable would determine how much it would cost to import it. The judge who decided the case ruled that the division wasn’t about botany but cuisine, and declared that since it’s used as a vegetable, it should be taxed as one.

    SkepticalHealth: I gotta agree about fried okra. Ohhhhh that’s good….

  26. laproxdoc says:

    Okra – there is a wonderful product called Talk O’ Texas Crisp Okra Ickles – comes in regular and extra spicy – they are delicious, not at all slimy, and a wonderful accompaniment to summer barbeque burgers! Try it!

    Some serious solanine toxicity believers hold that the toxic arthritis effects last for about 6 months. A single tomato/potato/eggplant intake resets the clock so that you have to wait yet another 6 months to notice any improvement from eliminating them from your diet. Whew. A yoga teacher once said to me that she could see that I was still eating tomatoes, potatoes, and eggplant and suggested that my practice would be much better if I eliminated them. I changed teachers instead and yes, my practice is much better now, thanks!

  27. laproxdoc says:

    That was Okra Pickles, sorry for the typo…

  28. DevoutCatalyst says:

    Okra Ickles is what lilady calls them. I don’t eat them, they interfere with my mucus free diet.

  29. rmgw says:

    CC – there are plenty of recipes for tomato jam around -“a recipe where tomato is used the way a fruit would be”…………..

  30. lilady says:

    I located a tomato ice cream recipe:

    [devolves into giggling]

  31. CC says:

    And I found a tomato tart. It sounds wonderful, I must try it. Maybe this weekend.

  32. lilady says:

    @ CC: Tarte tatin made with tomatoes…and why not? Tomatoes in season are so sweet they would be a nice substitute for apple or pears.

    I still think okra is soooo icky. And, as much as I love tomatoes, I dislike biting into a cherry or grape tomato…so I halve them for salads.

  33. Our resident chiropractors are strangely quiet!

  34. Chris says:

    Maybe they are neutral on the nightshade issue.

  35. CC says:

    lilady: well, tomatoes aren’t in season right now where I am, but I believe canned whole tomatoes (which are packed when they are in season) might do since the recipe starts with blanching and peeling the tomatoes. This is now officially on my shopping list and I’m going to make it this weekend.

    I was just thinking this discussion of recipes on a medical site was thread drift, but then I guess an article about the (non-)poisonous properties of foods does kind of lead naturally into how those foods are eaten… :-)

  36. lilady says:

    On a *serious* note, I checked our the Chiropractor that SkepticalHealth provided a link to:

    I now know that I suffer from STS (Solanine Toxicity Syndrome)…not to be confused with (a) STD. I thought I had osteoarthritis affecting my hands!

    I am so impressed with this Chiropractor and will be ordering a huge supply of “Body Guard Supreme” which is a miraculous cure for a multitude of ailments.

  37. tmac57 says:

    Congratulation Dr. Hall for getting your say on acupuncture on the NPR piece this morning.Even though the piece was disappointingly skewed toward a pro-acupuncture view.I hope you write about this soon.

    (sorry to be off topic)

  38. Chris says:

    This is coming from my memory from long long ago, so the details might be fuzzy or even completely wrong. When I was in fourth grade (only three channels available on our black and white TV), I checked out a book from the library on myths and legends from the Americas.

    There was a story from the Inca about how the gods gave them the potato. They were fighting another group, and the gods showed them the potato. They were instructed to feed the fruit to their enemy, and for them to eat only the root.

    The fruit of the potato poisoned their enemy, and tubers became the staple of the Inca.

    I grew potatoes last year in a trash can. Being taken with a sale I bought five varieties for the price of four, and noticed there were different flowers on different varieties. The vines have very pretty flowers, and I think some fruit started to be formed. This year I only bought two varieties for my cut up trash can potato growing system.

  39. CC says:

    (Just in case anybody is wondering, the tomato tarte tatin is delicious.)

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