The Problem with Tomatoes (There’s good and bad)

By: Cat Ebeling 
Co-author of the best-sellers:  The Fat Burning KitchenThe Top 101 Foods that Fight Aging & The Diabetes Fix

Here in Colorado, we have short growing seasons, and our backyard crop of tomatoes is winding down, but finishing with a bang. We have been picking oodles of gorgeous big, luscious ripe heritage tomatoes, and have so many it’s hard to know what to do with them all!

Tomatoes are considered a health food in most circles; known for having rich supplies of anti-oxidants like lycopene, beta-carotene, folate, potassium, vitamin C, other flavonoids, as well as other nutrients. Tomatoes are most famous for their copious amounts of lycopene, which is well-known as a cancer-fighting substance—especially prostate cancer in men. Lycopene has also been scientifically shown to stop or slow cancerous tumor growth as well, helping to fight against lung, stomach, colon, oral, breast, and cervical cancers as well.

Tomatoes contain other antioxidants as well including zera-carotene, phytoene and phytofluene, that fight inflammation and diseases like heart disease, cancer, diabetes, arthritis and dementia. Their powerful antioxidants also protect against high blood pressure, and help to lower cholesterol, as well as improving blood vessel health.

Tomatoes also protect against macular degeneration, one of the leading causes of blindness in elderly people. The generous amount of vitamin C in tomatoes slows down aging, and keeps skin looking young and wrinkle-free, as well as offering nutrients that protect and help rebuild strong bones.

All sounds great, right? But can tomatoes be bad for you in any way?

Well it depends on the amount of tomatoes you eat, and whether you are sensitive to nightshades. Although tomatoes come loaded with beneficial nutrients, keep in mind that they are a nightshade vegetable that can aggravate health conditions for some people.

Many credible medical establishments, including the Cleveland Clinic, encourage avoidance of nightshades to relieve arthritis pain and other inflammatory diseases. This study shows a positive relationship between the elimination of nightshades and an improvement in arthritis symptoms.

If you already struggle with food sensitivities or allergies, or have any type of inflammatory or autoimmune disease, you should definitely pay attention to nightshades. Symptoms include joint pain or swelling, digestive issues, heartburn, irritable bowels, or any red or inflamed areas of the skin. Some nightshades can even exacerbate asthma and breathing difficulties as well.

Nightshades are a group of plants that are a part of the Solanceae family. Many nightshades are very common—in fact, most of us eat them every day. Tomatoes are a nightshade. The major plants that we eat most of that are in the nightshade family include tomatoes, potatoes, peppers, and eggplant.  There are several others as well, but they are generally not consumed in large amounts by most people.  The 4 listed above are the nightshades most eaten in large quantities.

blankNightshades are known to cause a type of inflammation through a compound called “solanine” which can irritate the digestive tract, and even cause breakdown in red blood cells. Nightshades can cause worsening of arthritis in many people, as well as exacerbating irritable bowel syndrome, heartburn, acid reflux, and other GI issues. Solanine is primarily found in potatoes, while the tomato version of this is called “tomatine”.

This alkaloid is concentrated in the green portions of the plant. While you wouldn’t eat the green leafy part of a tomato, green tomatoes, as in ‘fried green tomatoes’ contain more concentrated tomatine amounts. Tomatine and solanine alkaloids can irritate the gastrointestinal system and even affect brain neurotransmitters like acetylcholine.

Tomatoes can also worsen acid reflux and heartburn conditions in many people and the seeds can be very harmful to those who are prone to diverticulitis (an inflammatory disease of the large intestine).

So while tomatoes can have a lot of health benefits if eaten in moderate quantities, if you happen to have joint pain, arthritis or heartburn, it may be worthwhile to lay off them and the rest of the nightshade family for a month or so to see if they are causing a problem for you, or worsening your symptoms. However, the nightshade family includes a lot of relatives, so its important be sure to include all of them if you are going to avoid them. These include:

  • ­All varieties of tomatoes
  • ­Tomatillos
  • White potatoes (sweet potatoes are OK and are not nightshades)
  • Eggplant
  • ­Okra
  • ­All varieties of peppers—hot or sweet
  • Goji berries
  • ­Sorrel
  • ­Gooseberries
  • Tobacco
  • ­Paprika
  • ­Cayenne pepper
  • Chili powder

Mike’s Note:  To add on to Catherine’s comments, I’d like to add that I think the main harm from nightshades can come from over-consuming them on a regular basis year round… If you think about it, part of studying Paleo principles of nutrition are that many foods would have only been eaten seasonally by our ancestors, and not continuously year-round.  

My personal theory on nightshades is that they have good compounds AND bad compounds in them, but our ancestors probably only ate them for 2-3 months of the year, and not 12 months of the year.  Therefore, it’s not that tomatoes, peppers, and potatoes are bad for us entirely…they’re actually good for us in many ways… But, they’re probably best cycled in and out of our diet, or only eaten once or twice a week as opposed to every single day.  That way, you benefit from some of the good nutrients in them, but without over-doing the bad compounds that nightshades can contain.  

Once again though, if you have Arthritis, severe digestive disorders, or an autoimmune disease, it’s best to avoid nightshades most of the time, or at least for a certain time period to see if they are affecting you negatively.


About The Watchdog

Mike Geary has been a Certified Nutrition Specialist and Certified Personal Trainer for over 15 years now. He has been studying nutrition and exercise for almost 25 years, ever since being a young teenager. Mike is originally from Pennsylvania, but has fallen in love with mountain life and now resides in the picturesque mountains of Utah. Mike is an avid adventurist and when he’s not spending his time skiing, mountain biking, hiking, or paddleboarding on the lake, he has enjoyed skydiving, whitewater rafting, piloting an Italian fighter plane (seriously), scuba diving, heli-skiing, and traveling all around the world, enjoying learning about different cultures. At the age of 40, Mike now feels healthier, stronger, and more energetic than when he was 20... All because of a healthy lifestyle and great nutrition!

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  1. Mike this is a great article by Cat, and also your comments. I love these foods, I eat them everyday. I don’t seem to have any of the problems associated with tomatine and solanine. My question is should I still limit my intake? If the answer is yes this is going to break my heart. This is my go to breakfast, I saute bell peppers, mushrooms, broccoli, spinach, kale, sundried tomatoes, over low heat in coconut oil until they’re perfect, then I crack 3 eggs in there and stir it up until done. Top it with tumeric, black pepper and Louisiana hot sauce (which is more peppers). I love it, my wife thinks I’m crazy, it’s takes me 20 minutes. But my body seems to say Thank you. 😀

  2. There is a lot of sound advice and information in this article. Yet it is not new. George Oshawa, of Macrobiotic fame, 70 years ago, spoke of the dangers of nightshade foods, covering all this ground, and stating that traditionally in South America, where potatoes and tomatoes come from they were eaten as medicine – that is given specifically for a short period time for a specific condition. Consuming them as folk do on a daily basis, creates a serious ”’yin”’ state of being.

    Sometimes when folk talk of the desire and ”need”’ to consume these foods, and tobacco, they cite the case that the foods contain masses of Vitamin C. My answer to that is, yes, so does belladonna (deadly nightshade), so it is ‘doing you the world of good’ on it’s way to killing you, in a short space of time!

    • I stopped eating nightshades over four years ago. I did it as an experiment, hoping it would fail. I loved my tomatoes, peppers, and potatoes. Much to my disappointment, it worked. My severe plaque psoriasis completely cleared up and has not returned! While it didn’t completely take away my pain from the psoriatic arthritis, it helped immensely! Looking back, I feel like I was poisoning my own body. Never going back.

      • You were far more likely to have the skin problems NOT because of the tomatoes but because of the starchy garbage called potatoes that cause that problem.

      • Thanks for your story. Going to give it a try.

      • Hi Paula – I agree. I stopped eating white potatoes 16 years ago and severely limited the other nightshades about 5 years ago. I have a form of lymphoma that affects my skin – red dry patches that can eventually turn into tumors. BUT, once I stopped the nightshades, I have not had a relapse of the skin patches since…5 years!!! I do miss tomatoes and bell peppers so much. It is hard to find recipes without them and my diet is quite boring.

  3. I suffer badly from Nightshade plants so I welcome this great article. I believe it is the first food group you should look at for health issues. I don’t believe our ancestors would have gone near these plants as they were very aware of poisonous plants. They used their bottom lips as toxin sensors. They certainly wouldn’t have eaten a dirty potato root.

  4. I have read that peeling and deseeding tomatoes removes most of the “harmful” elements in tomatoes. I would absolutely die if I couldn’t have my tomato sauce, and I make my homemade sauce w peeled, deseeded tomatoes.

  5. “For some reason, most people don’t seem to care about this topic until it’s too late and they have a heart attack or even DIE”

    Too late or not, I think at that later stage you would be past caring about any particular topic.

    • I am 89. I just found out that I should not eat tomatoes or anything spicy because of my OAB. I love tomatoes & at this time in life, I am not giving them up. I will just put up with the OAB. I was on meds & was getting side effects from them that were worse than the OAB. In fact one side effect was that it could make the OAB worse & it did.

  6. Teena Bezuidenhout

    Solanine is mostly found just under the skin of potatoes especially when they start turning green.

    • Bell peppers are extremely dangerous for me. It took some time to figure out what was causing my severe dizziness and nausea. But even a hint of bell pepper in my food sets off a reaction that lasts at least 24 hours. Tricky because they get snuck into so many foods. I also react to fresh tomatoes but not tomato sauce and goji berries. Avoid all nightshades at this point!

  7. I have need DX with RA. I suffered for two years with swelling mostly my fingers- I have never liked tomatoes and rarely way them but have grown my own to have for summer eating. I have decided after reading this I will obtain from all nightshade foods and see how I feel. Thank you all for your posts. It helps folks make better choices and understand why they cause issues for some people.

  8. #1 cause of arthritis pain is milk, and dairy products like cheese, gout is caused too

    • What a oxy moron (sp?) Milk
      And dairy so good for many things you would think a large % would have arthritis. ?? I am desperately looking for the Perfect diet for myself
      Not weight loss just for being 100 % totally healthy. One thing gets better and something else pops up.. Does this diet for everyday exist?

      • Milk intolerance is quite common…causing gastrointestinal problems and can cause skin problems. I have family who could have cream, whole milk and as they got older, the sensitivity and gastrointestinal problems increased. Most of them had to give up all milk products by age 55-60. My family has one side Italian..severely changed a lot of food..cheeses are dairy as is milk.

    • You may want to describe Mediterranean diet a bit more. That “diet” does use those begs. Maybe a certain region perhaps?

  9. Ashwaganda is a nightshade also.

  10. Actually, our Paleo ancestors would not have eaten nightshades or most other vegetables because they are inventions of modern day man.

  11. Would freshly squeezed tomato juice be safe, as I presume the skins and pips would be discarded?

  12. Hi, Please can you let Cat Ebeling know that gooseberries are not members of the nightshade family? They belong to a different group of plants: Saxifraga.
    Kind regards
    Maria Cash

  13. Isn’t the Mediteranean Diet supposed to be healthy and doesn’t it contain a lot of the nightshades , especially tomatoes and peppers.

    • Veronica PeÒa y Lillo Fuentes

      No , I personally know many of my family and friends had digestive problems and most people suffered from
      arthritis at a very young age!
      they never adressed or knew what the reason was …. hope some one-body will tell them NOW!

  14. Was this published in the Medical Journal sometime? interesting information indeed .

  15. Did not realize how sensitive I was to these nightshades
    Ate fresh tomato sandwiches while visiting my family in CO for several days. Went to our fav Italian Restaurant for Eggplant Parm, could not walk or climb the stairs. My granddaughter reminded me,Grammy too many tomatoes this week
    Took triple my Tumeric for several days until the inflammation went down
    Thank you for this most informative article

  16. Hey just wanted to say you didn’t mention Lectins they are in tomatoes and are not good was just curious. Thank you.

  17. I’ve been aware of the problem with nightshades for many years & would add the following observation. People who are sensitive to solanine tend to be particularly sensitive to eating just one or two of the nightshade vegetables & can eat others w/o significant problems. for my wife it is peppers. she can eat tomatoes & potatoes without any noticeable ill effects but if she eats something with paprika on it she will feel back pain within minutes. for my mother, it was white potatoes.

    If you have any sort of inflammatory condition I would suggest doing the month w/o any nightshades & then (if you notice improvements that would suggest that the nightshades are a factor in your inflammation) individually, sample a nightshade vegetable to see if you notice inflammation. You may well find out that you can eat most of them without ill effect. Of course, you can even eat the ones that exacerbate your inflammation if you desire at a particular instance. It just means that you are the one in charge of whether or not you hurt rather than being a victim of something unknown.

  18. Gooseberries are not nightshades!

    Cape Gooseberries are. Physalis family.

  19. This amazes me because when I was a child my food allergy test came up that I was “allergic” to Tomatoes and Potatoes. The two foods I love. Now as an adult I suffer with chronic pain from inflamation. I removed gluten as this stopped a major part of it and also getting sick so easily and stopped having sinus infections. But, I still have inflamation and couldn’t figure out why. I will try to remove these foods and see what happens. Im Italian so this is a huge challenge. I just don’t get how ancestors in Europe ate tomatoes, is it the different environment which it grows that makes it better?

    • Tomatoes and potatoes (I don´t know about the other nightshades) come originally from South-America. The ancestors of the other parts of the world could never have eaten them before Columbus introduced them to Europe (from where they later spread to other continents).

      • No. They originated in South America!
        The potato was the first domesticated vegetable in the region of modern-day southern Peru and extreme northwestern Bolivia[1] between 8000 and 5000 BCE.[2] Cultivation of potatoes in South America may go back 10,000 years,[3] but tubers do not preserve well in the archaeological record, making identification difficult. The earliest archaeologically verified potato tuber remains have been found at the coastal site of Ancón (central Peru), dating to 2500 BC.[4] Aside from actual remains, the potato is also found in the Peruvian archaeological record as a design influence of ceramic pottery, often in the shape of vessels. The potato has since spread around the world and has become a staple crop in most countries.
        The tomato ( or) is the edible berry of the plant Solanum lycopersicum, commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word, from which the English word tomato derived. Its domestication and use as a cultivated food may have originated with the indigenous peoples of Mexico. Wikimedia

  20. An attack on tomatoes that doesn’t mention Lectins – What will Steven Gundry say ?

  21. If are reactive to nightshade family, stop eating any for 90 days, not one month, to see better improvement. If make any mistakes, 90 days starts again. It is possible to regain tolerance for offending items using 90-day limit (and this can work for variety of food intolerances).
    Nightshades to be avoided: tomatoes, potatoes, eggplant, capsicum, chillies, paprika.

  22. I take meds for depression and various foods affect my mood, especially chocolate but also tomatoes, soy, cashews, walnuts and pistachios.

  23. Thanks David. I have along list of auto immune diseases and I have found that I can no longer eat potatoes . They upset my insides as if I had eaten a dose of poison. But I never experienced any issue with tomatoes and almost reluctant to give them up. I have the most ridiculously healthy diet in the world as I’m celiac too and tend to avoid grains alltogether. I’ll give them up if someone tells me that they are working against me even if I have no symptoms when I eat them … thanks all!

    • Gio – potatoes absolutely kill my stomach. I finally figured it out when I was 27. I didn’t notice the effects of the other nightshades until I was in my late 30s..they caused me inflammation in my joints and skin rashes. I notice it right away when I eat them now.

  24. I used to eat a lot of tomatoes and I suffered badly with anxiety. Since removing them from my diet, that has significantly reduced. From my own research, I discovered that tomatoes are high in glutamate and that some people have problems with the glutamate/glutamine/GABA pathway, so that the glutamate, an excitatory neurotransmitter, doesn’t get properly metabolised to GABA, a calming neurotransmitter. Tomatoes are also very high in salicylates and histamine, both of which can cause many people real problems. No wonder that they were considered by many Europeans to be poisonous when they were brought over from the Americas!

  25. I don’t believe any of this bad stuff about tomatoes.The natural health book by Dorothy Hall says its not tomatoes giving you pain,its the movement of uric acid being removed from your body.I have had this book since the 70’s and its very helpful and easy to understand about all health

  26. How about the fermented green tomatoes? Do they still contain high amounts of tomatine? Thank you!

  27. I thought I read that tomatoes as sauce are okay. Does anyone know if this is true?

  28. Perhaps there are no two people the same, even when having the same disease. I have arthritis. Since gluten and dairy have such a bad rap for people with autoimmune diseases, I cut them out for about two months. I didn´t feel any improvement at all in my health and I unwillingly lost several kilos. When I introduced them back I recovered my weight, and I didn´t feel any worse either. After reading about the impact of nightshades on arthritis I cut them all out overnight (I used to eat potatoes several days a week and tomatoes every now and then; I didn´t eat much of the other nightshades). The thing is that the pain I had had in my wrists for years diminished considerably in a matter of a week!!!, and it got better and better. I haven´t eaten any nightshade ever since (this is already almost one year ago). If this is the price I have to pay for feeling well, I´ll pay it.

  29. There is a gene that I carry “atypical BuChe”, (this same gene is connected to those that had Desert Storm syndrome), it actually makes it problematic for me to consume nightshades and tolerate organophosphates i.e. glyphosate/pest control/chemical sensitivities – which all my life I’ve had reactions to these exposures when no one around me did. So for some of us, there”s a legitimate reason behind these problems. I did the 23andme and then ran my raw data through another site for health info, unfortunately the site was bought out and no longer does this, it was so reasonably priced too – but it provided some very enlightening info for me. Most importantly keep a food diary and listen to your body.

  30. I think that people need to realize that not everyone is the same and that nightshades affect everyone differently. I eat a lot of tomatoes, because of their health benefits and do not notice any side effects, although I may be susceptible to joint pain from other foods. I don’t think that tomatoes, pepper, potatoes should be given a bad rap totally, since food can be eaten in moderate amounts, seasonally or in conjunction with other hers, spices, etc. which may mitigate the possible effects of nightshades. Dr. Gundry and other health experts do a disservice by making all of these statements in very broad, sweeping generalizations and don’t pay enough attention to other research which may conflict or shed further light on the way nightshades operate. I think the Mediterranean diet works despite the fact that contains nightshades.

  31. In my own opinion, I feel that people who experience problems with certain foods, either eat too much of them, or have some kind of digestive, or vitamin deficiency, or both. An allergy to foods, that are normally healthy for most of us to eat, is a warning sign, not to avoid the food; But, to find out why the food, especially a natural food like tomatoes, is causing the problem.

  32. The poison is in the dose. The watch-word is MODERATION.

  33. I once had a professor at Harvard who used to say: Nothing to excess…especially moderation:)

  34. ‘ happy to see tobacco included. Though tobacco for smoking and chewing is subject to the most rigorous testing for residual agro chemicals, I have never seen other than here, comment on the toxic fractions of the plant. I wonder therefore if there may be compounds that are cancerous, neurotoxic and otherwise.
    Decades ago, insinuations outside the industry would be vigorously attacked, even to the blatant untruth that: “it’s good for you.”
    What some people will do for a dollar is putting it politely, shameful.

  35. Interesting article, thanks. Like some others, I’m surprised it doesn’t mention lectins, about which Dr Steven Gundry has given stern warnings. My take on it is that the skin and seeds are the parts to avoid. So in summer I like to eat gazpacho, the Spanish cold tomato soup. This is smooth and well-filtered, and I hope I don’t get any of the bad stuff!
    And home-grown cherry tomatoes are so delicious that I’m convinced they do more good than harm.

  36. mike.are bell peppers of any color and yukon gold potatoes(not white), included in your category of niteshade? aldo paprika, chili powder, and cayenne in moderation okay?

  37. i would like to send this item to my daughter but cannot manage to find a method to do so.
    Is there a method I can use to forward it?

    • Try printing article, scan it and save to your documents. Then you can email it to your Daughter or you can right click on article and send link by email. Your Daughter might have to copy the link to her browser to open. Hope this helps.

  38. Okrs is not a nightshade. It is a mallow.

  39. I never had any allergies until about eight years ago. Then something triggered systemic inflammation and ever since I’ve been allergic or sensitive to nightshades, all grains, tapioca, alcohol, vinegar, the tannins in coffee and tea, apricots and a slew of other things. Ever since reading Dr. Gundry’s book back then, I stopped eat fresh tomatoes and when I make sauce or chili I open up the canned tomatoes one by one and rinse all the seeds out before using them. But every time I eat something with tomatoes, peppers, paprika, chili powder or any of the above mentioned foods, my face gets slightly swollen, particularly under my eyes, and I get itchy. If I eat the food two days in a row, it gets worse and triggers eczema. If I don’t eat the foods I don’t have a problem. I find the nightshades particularly problematic and try not to make dishes that include them very often, but do occasionally have to make spaghetti sauce and chili to appease my husband. As it is, I’ve been able to stay healthy and avoid further problems by keeping away from these foods for the most part.

  40. Foods containing “anti-nutrients” can be safely consumed if prepared the right way. Lectins are destroyed by cooking, especially pressure cooking them. Peeling and removing the seeds also decreases toxin ingestion. Another method is fermenting. Steaming also reduces oxalates. Blending raw leafy greens and adding powdered calcium will neutralize oxalates and make them safe to eat. Don’t demonize these wonderful foods just because “experts” are unaware of how foods should be prepared. Ancient humans knew those secrets VERY WELL.

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