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Nightshades PDF Print E-mail
Written by Garrett Smith, NMD   
Tuesday, 30 March 2010 00:25

Read this article in: Dutch

Problems from these Popular Foods Exposed to the Light of Day

The nightshades are members of an enormous family of plants called Solanaceae, represent a huge family of plants. The ones that concern us in the Western diet mainly include tomatoes, potatoes (not sweet potatoes or yams), eggplant and peppers—this means all peppers including chili peppers, habenero, cayenne pepper and paprika (not peppercorns, see sidebar). Paprika is a sneaky one, showing up in lots of flavoring mixes and often under “spices” on ingredient labels. Other nightshades include goji berries (the new darling of the antioxidant crowd), ashwagandha (an adaptogenic herb from Ayurvedic medicine), Cape gooseberries (not normal gooseberries), ground cherries and garden huckleberries (not blueberries).

I’m a licensed naturopathic physician in private practice, and I will admit right off the bat that I am biased against nightshades. I used to eat a ton of foods in the nightshade family, but now I avoid them as much as possible. I am one of those who is very sensitive to these foods. In my medical practice, I treat pain often. My goal in pain treatment is pain relief. In my opinion, pain management—that is, long-term painkillers, without a goal of true pain relief—is for suckers. For me and many of my patients, nightshade avoidance is the answer to long-term relief from pain.

Why should you care about this? It’s likely that you enjoy eating these foods and can’t imagine that they are bad for you in any way. Well, if you suffer from inflammation, joint pain and cracking, avoiding nightshades will lessen your pain, whether or not the nightshades are the true source of the pain. Are you sensitive to weather changes? This can be an indication of nightshade sensitivity. Muscle pain and tightness, morning stiffness, poor healing, arthritis, insomnia and gall bladder problems—these can all be caused by nightshades. Nightshades can also cause heart burn or GERD—a lot of people already know they react this way when they eat peppers or tomatoes.

Like soy, most nightshades are relative newcomers to European/Western diets. The tomato came to North America in the very early eighteenth century. It was termed the “love apple” and grown first as an ornamental. That means people grew it because it is pretty, yet they did not eat it. Why did they not eat it? They thought the tomato was poisonous. The leaves of the nightshade family are indeed overtly poisonous (livestock farmers know this well) and people avoided the fruit as well.

During a famine in 1782, Scottish highlanders complained of dropsy (an old term for edema or swelling, often associated with congestive heart failure) when they ate abundantly of potatoes.1 Russian prisoners of World War II returned with advanced cases of dropsy, which was blamed on heavy potato consumption.2 An old saying in New Hampshire in 1719 was that the white potato shortened men’s lives.

Eggplant was also first grown as an ornamental, a decorative plant. It was not eaten until relatively recent years in North America. According to Dr. Norman Childers, author of The Arthritis Diet, peoples of the Mediterranean area previously believed that the eggplant would cause insanity if it was eaten daily for a month, in fact, it had the nickname of “mad apple.”3 How many foods that you eat have a reputation like that?

It’s extremely easy to overdose on nightshades in Western culture, especially if you are a foodie. Let’s say you have salsa on your eggs at breakfast, potato salad at lunch, and eggplant with peppers along with other spicy dishes at dinner. This is a large amount of nightshades, eaten three times per day, in multiple combinations. It’s very hard to avoid the nightshades, believe me, it’s a lot of work! This can be easily demonstrated by reading the menu at any restaurant— nightshades have become ubiquitous. Nightshade sensitivity, in terms of the vigilance needed to keep them out of the diet, is almost as bad as gluten sensitivity!

For those of you who think you have tried “everything” for your arthritis pain, tried this and tried that but haven’t tried avoiding nightshades— in my opinion, it’s something you do need to try. I can tell you as a naturopathic doctor that I have tried many different remedies for my middle back pain. Nightshade avoidance got rid of 90 percent of it. If you’re one of those people whose pain treatments (be it chiropractic, acupuncture, laser, energy medicine, whatever!) provides only a day or two of relief, you’re quite possibly nightshade sensitive.

A physical therapist once told me that if a patient isn’t responding to treatment, one of the first things to consider is nightshade sensitivity— there is simply nothing else that anyone can do to help somebody in pain when nightshade sensitivity is the cause—because once they eat some nightshades again, their pain will return as it was before. Sad but true, as I have witnessed many times in my practice.


The nightshades are considered a “calcinogenic” plant; that is, they cause calcinosis, which is a toxic calcification of soft tissues when eaten by animals. This happens because they contain calcitriol (1,25-dihydroxy vitamin D), the most active form of vitamin D. Please note that calcitriol is not vitamin D3 (cholecalciferol). This is an extremely important distinction, as you will see.

In humans, calcitriol is normally the end product of vitamin D metabolism, so let me start at the beginning. Cholecalciferol, or vitamin D3, is produced in the skin by the action of sunlight or can be consumed in food or supplements. In the liver, vitamin D3 is transformed into calcidiol (25-hydroxycholecalciferol, the compound that we test in the blood as a measure of vitamin D status); then the kidneys transform calcidiol into calcitriol (1,25-dihydroxy vitamin D).

Calcitriol is an extremely potent hormone, thousands of times more potent than vitamin D3. It has been said that calcitriol is the most powerful hormone in the human body. Production of calcitriol is very tightly regulated by the kidney. Why is it so tightly regulated?

Calcitriol signals the intestines to absorb calcium from our diet. While we absolutely need calcitriol to maintain proper bone density, too much calcitriol, from any source, leads to hypercalcemia, also known as high blood calcium. The body does not like this situation and wants to get the calcium levels back down to normal as quickly as possible, as an imbalance of minerals in the blood particularly affects the heart. The quickest solution for the body is to deposit the extra calcium into the soft tissues. Each hypercalcemic episode likely lasts for only a short while, however, each episode leaves a small deposit behind. Over time, these deposits lead to the condition known as calcinosis.

Overconsumption of calcitriol from nightshade foods can circumvent the kidney’s control and over time lead to calcium deposits in the soft tissues such as the tendons, ligaments, cartilage, cardiovascular tissues, kidneys and skin. Osteoarthritis is basically calcium deposits in the soft tissues of joints. Chronic hypercalcemia can lead to generalized vascular (blood vessel) calcification, which is coronary artery disease. Nephrocalcinosis is calcification of the kidneys.

We are not supposed to bypass the body’s control mechanisms for calcitriol. Nightshades do this to our detriment. Many of us do not notice because it happens so slowly and gradually.

What causes arthritis? The conventional view is that arthritis is the result of the joint “wearing out.” If this were the case, then arthritis would always be accompanied by inflammation. Think of parts in a car. If they “wear out” due to friction, there is heat, which could be likened to inflammation in our bodies. However, osteoarthritis typically has no inflammation, so it really should be called osteoarthrosis.

What if calcinosis could explain most, if not all these osteoarthritic changes? Instead of your joints wearing out, what if nightshades and their calcitriol content were causing the joints (cartilage, tendons, ligaments) to slowly calcify? Bone spurs are calcium deposits in tendons or ligaments. Many people are told that they have “no cartilage left” in their joints, but what if the truth was that the cartilage had slowly calcified? It would be nearly impossible to tell the difference between the two situations unless one knew exactly what to look for.

Scleroderma is a widespread connective tissue disease that involves changes or hardening in the skin, blood vessels, muscles and internal organs. The cause is said to be unknown. Could it be caused by nightshades, leading to calcinosis?

Some physicians are giving calcitriol or its analogs for simple vitamin D deficiency. This is overkill and not good for the system. In bypassing the body’s control systems we are creating the same situation I described above. If your doctor insists on using calcitriol, ergocalciferol (vitamin D2, an unnatural form of vitamin D made by irradiating a fungus with ultraviolet light), or any other expensive analogue of vitamin D other than vitamin D3 (cholecalciferol), you may want to find another doctor who is more educated in vitamin D supplementation.Please note that there are medical conditions where administering calcitriol is necessary, but simple vitamin D deficiency is not one of them.

According to Medline, common side-effects of calcitriol injections include weakness, headache, somnolence, nausea, vomiting, dry mouth, constipation, muscle pain, bone pain and metallic taste.4 Note the muscle and bone pain—do these sound like nightshade problems I’ve mentioned already? The liver and gall bladder can be affected, resulting in pale or fatty stools, an indication you are not digesting your fats well. Yellowing of skin or eyes (jaundice) is another symptom, indicative of liver issues. Hallucinations can happen, and a rare side effect is overt psychosis. Remember what was said to happen when one eats eggplant every day for a month?


Vitamin D Pathway


Solanine is a glycoalkaloid, that is, a non-protein compound containing nitrogen. It is a potent poison found in species of the nightshade family, especially potatoes and eggplant. It can occur naturally in any part of the plant, including the leaves, fruit, and tubers.

Solanine poisoning is primarily displayed by gastrointestinal and neurological disorders. Symptoms include nausea, diarrhea, vomiting, stomach cramps, burning of the throat, cardiac dysrhythmia, headache and dizziness. Hallucinations, loss of sensation, paralysis, fever, jaundice, dilated pupils and hypothermia have been reported in more severe cases.5

Potatoes naturally produce solanine and chaconine, a related glycoalkaloid, as a defense mechanism against insects, disease and predators (humans included). Potato leaves, stems and shoots are naturally high in these glycoalkaloids. When potato tubers are exposed to light, they turn green and increase glycoalkaloid production. This is a natural defense to help prevent the uncovered tuber from being eaten.

In potato tubers, 30–80 percent of the solanine develops in and close to the skin. If the potato looks green under the skin, throw it away; likewise if it has begun to sprout, just discard it.

How toxic are these compounds? The World Health Organization sets an upper limit of 20 mg per 100 grams of solanine per fresh weight of potato. Above that limit, they cannot be sold in stores, as they are considered too toxic for human consumption.6

Solanine and related glycoalkaloids are poisonous because they are acetylcholinesterase inhibitors—they inhibit the breakdown of acetylcholine, resulting in increased level and duration of action of this neurotransmitter. What does this mean? They cause prolonged muscle contractions. This is why people who are sensitive to nightshades or eat a lot of them often feel stiff when they wake up in the morning or sit for extended periods.

Studies with animals indicate that solanine causes cell membrane disruption in the digestive tract—exacerbated irritable bowel disorder in mice,7 gastrointestinal tissue destroyed in Syrian hamsters.8 It affects the gene expression of the human intestinal cell linings and also inhibits proteolytic enzyme activity.9 Solanines also destroy human liver cells in vitro.10

I have found fourteen research reviews linking potato blight in Ireland with birth defects in the following years.11 Potato blight involves a particular fungus growing on potatoes, causing them to kick in their defense mechanisms and make high levels of solanine. In my opinion, it would be wise for pregnant women to avoid the nightshades.


All nightshades contain nicotine, which is why they can be addictive. Is nicotine a problem when we eat it? A large body of research shows that nicotine consumption inhibits proper healing. In one study, nicotine delayed tendon-tobone healing in a rat shoulder—the equivalent of our rotator cuff.12 A follow-up study by the same authors showed that delayed healing in tendon-to-bone injuries resulted in inferior permanent healing of the area.13


Capsaicin is an alkaloid found in hot peppers. We hear a lot about capsaicin supposedly having anti-inflammatory properties, but it actually is an irritant for mammals, including humans, and produces a sensation of burning in any tissue it comes in contact with.

Spicy peppers are the only plants that contain capsaicin, to my knowledge. The active ingredient in pepper spray is capsaicin. It can shut down the lungs—this is why some people have died from pepper spray. Asthmatics would do well to avoid capsaicin in general. They actually use capsaicin in animal studies to stimulate something very much like an asthma attack.

Substance P is released from the terminals of specific sensory nerves. It is found in the brain and spinal cord and is associated with inflammatory processes and pain—it acts as a neurotransmitter to carry pain signals to the nervous system. Capsaicin makes your nerves release almost all the substance P they have, and researchers have therefore suggested that drugs containing capsaicin can help reduce pain. For example, there is an over-the-counter cream containing capsaicin that is promoted to help deplete substance P from local nerve endings and relieve pain.

However, inducing massive releases of substance P on a regular basis is like taking speed until your adrenals run out of adrenaline; it leads to a chronic local or systemic depletion of substance P. Substance P is necessary for proper healing. The brain gets a signal from substance P telling it that something is hurt and needs to be fixed. So when you have diabetics using capsaicin cream for their neuropathy, they feel better—the pain signal is gone—but they are inhibiting the healing process.

A recent study looked at the use of capsaicin in insulin-dependent diabetic rats.14 The standard explanation for type 1 diabetes is malfunction and death of the insulin-producing islet cells in the pancreas. Another theory holds that malfunction of the pain nerves surrounding cells in the pancreas can cause type 1 diabetes. Researchers have found that the islet cells in diabetics are surrounded by large numbers of pain nerves that signal to the brain that pancreatic tissue is damaged. When the researchers injected Substance P into the rats, the islet cells began producing insulin normally almost immediately. They also produced insulin for about a month when they were injected with capsaicin.

Capsaicin depletes substance P. Although this study was reported as showing a beneficial role for capsaicin, the proper conclusion is that capsaicin is likely horrible for diabetics and their blood sugar control. I have witnessed firsthand the negative impact of consuming peppers on blood sugar control in some of my diabetic patients (the ones who keep diet and blood glucose logs).

Capsaicin receptors have been found in arthritic joints. When they inject capsaicin into mouse knee joints, it reduces blood flow.15 That’s a bad thing. Blood is what heals us. When neonatal rats were given capsaicin, their immune markers were depressed for ninety days.

In humans, increased consumption of peppers is associated with an increase risk of nasopharyngeal carcinoma and stomach cancer. Researchers found seventeen times (!) the risk of stomach cancer in people who self-rated themselves as high consumers of peppers.16 In people who had tissue biopsies of colon polyps, dysplasia and adenocarcinoma, researchers couldn’t find any substance P in those biopsies. Where would it have gone? What they found was the presence of capsaicin receptors instead.17


How do you find out whether nightshades are causing your medical problems? For many, no relief comes until the diet is totally clear of all these nightshades for at least six weeks. Many people notice an improvement in their pain; sometimes it goes away completely.

If the person has strictly avoided the nightshades for six weeks, yet still doesn’t believe their pain has decreased, I suggest that they do a “nightshade party day”: salsa and eggs for breakfast, tomato and eggplant for lunch, potatoes for dinner—just have it all, and have a lot. Eat as much as you can in one day and then watch for symptoms over the next two days. Often there is a delayed onset reaction—there is for me.

But the real question is, why are some people more sensitive than others? Nutrient deficiencies certainly come into play. For example, if you don’t have enough magnesium, you will be more prone to calcinosis. Deficiency in vitamin D may exacerbate the problem. The speed at which one’s liver and kidneys detoxify these compounds plays a huge role, and this is dependent both on genetics and nutrition.

A key nutrient is vitamin K2—Dr. Price’s famous Activator X. I love this study on vitamin K2: The Effect of Vitamin K2 on Experimental Calcinosis. 18 They gave rats calcinosis by giving them way too much vitamin D2. D2 tends to cause calcinosis anyway. What did they find? A high dose of vitamin K2 suppressed experimental calcification of soft tissues induced by vitamin D2. So if you want to avoid problems with nightshades, be sure to eat goose liver, cheese, fatty grass-fed meats and pasture-fed butter—and take your butter oil.

If you suffer from osteoarthritis and you feel like you have some catching up to do in terms of resolving calcifications, you may want to take a vitamin K supplement. I use Allergy Research Full-Spectrum Vitamin K softgels, which combine vitamin K1 (phytonadione) and vitamin K2 (as both menaquinone-4 and menaquinone-7, known as MK-4 and MK-7, respectively).


Recently after a power-lifting meet, I felt like cheating on my diet. I called it an “experiment.” My old favorite food was pizza—the nastiest combination of all the nastiest foods there are, at least for me. We had it with peppers, sausage containing paprika, tomato sauce, gluten and dairy, all of which I’m sensitive to. I felt that this was my chance to test my vitamin K hypothesis. I took two Allergy Research Full-Spectrum Vitamin K softgels with the meal, along with digestive enzymes and some buffered vitamin C. Normally the enzymes and the buffered vitamin C don’t help me much. However, this time, when I had loaded up on vitamin K2, I had no day-after morning stiffness and none of my middle back pain returned. I’ve only done the experiment once at this point, but that’s what I found.

Even if you are one of those lucky people who don’t seem to have trouble with nightshades, in my opinion it’s a good idea not to overdo. Avoid having nightshades with every meal; we are far too reliant as a culture on potatoes, tomatoes and peppers. Vary your diet so you are not so dependent on these foods. Sweet potatoes, yams and parsnips are good substitutes for potatoes. You can steam cauliflower and mash it with butter and cream. As a substitute for chili pepper, use wasabi, horseradish, mustard powder, ginger, or freshly ground peppercorns. There’s no good substitute for tomatoes, so learn to use them sparingly.

Cooking does reduce the solanine levels in potatoes somewhat,19 and may even help reduce other toxins. So if you are eating nightshade foods, be sure to cook them, and cook them in butter or poultry fat—this is a synergistic combination because these fats provide vitamin K2. And you’ll end up eating less of the nightshade foods because when you cook in good fats, you are more quickly satisfied and end up eating less.

For those who are sensitive to nightshades, the best strategy is to avoid them completely for a long time, until you can completely heal. That means no potatoes, pizza, tomato sauce or Mexican food—but to live pain-free makes it worth the sacrifice.



Many of the alkaloids in the nightshade plants are extremely toxic; yet they have many uses in medicine if administered in extremely small dosages. They can serve as an antidote to poisoning caused by pesticides and chemical warfare agents such as sarin and VX. They are also used to halt—but not cure—many types of allergic reactions. Scopolamine, a commonly used ophthamological agent, dilates the pupils and thus facilitates examination of the interior of the eye. Nightshade compounds are also used as antiemetics in people prone to motion sickness or receiving chemotherapy.

Some of the most interesting uses of nightshades occur in homeopathy. Belladonna was one of the first homeopathic remedies, developed in 1799 by Samuel Hahnemann for scarlet fever, after he observed that symptoms of deadly nightshade poisoning closely matched those of scarlet fever. Belladonna now serves as a major homeopathy remedy for acute illnesses of sudden, violent onset. Other homeopathic remedies derived from the nightshade family include Stramonium, Hyoscamus, Tabacum, Dulcamara and Capsicum. Note that all of the “food nightshades” are used as homeopathic remedies as well. For those of you familiar with homeopathic theory and the “similimum,” it may start to make sense to you that eating significant amounts these foods could cause symptoms of disease in a healthy person.


Peppercorns are not the same as peppers; they are not members of the nightshade family. Peppercorns do not contain poisonous alkaloids. Fresh ground pepper is the best; pre-ground pepper is not good for you. It doesn’t taste very good and you’ll notice you have to use a lot more of it. Once the peppercorns are cracked open, the protective and flavorful essential oils begin to evaporate. This allows a type of aspergillus mold to grow, which then produces aflatoxin. You may be familiar with aflatoxin already, as it is very toxic to the liver and is the same toxin that occurs with peanuts. If you don’t eat peanuts for this reason, you would not want to use pre-ground pepper either. Freshly ground pepper helps with digestion—pre-ground pepper does not.


Tomatoes contain lycopene, which is one of the first things people mention when I suggest avoiding nightshades. Lycopene is a carotenoid found in almost any red, orange or pink fruit or vegetable; it’s simply highest in tomatoes. As with all of the fat-soluble carotenoids, to maximize absorption you’ll need to eat it with fat. We hear a lot about lycopene supposedly preventing cancer. However, in a study on prostate cancer in rats, when rats were given lycopene by itself, there was no observed decrease in cancer mortality when compared to the controls.20 However, when given tomato powder, there was a significant decrease in mortality rates from the induced prostate cancer. So there’s something in the whole tomato that protects against cancer and it’s not lycopene by itself.

The new theory in this reductionist way of thinking is that the anti-cancer substance in tomatoes is another glycoalkaloid called tomatine. While tomatine has been shown to inhibit and destroy cancer cells, it has also been shown to do the same to normal cells!21 This is the likely reason why many people get heartburn after eating tomatoes, not only because they are acidic (they are), but because the cells that line the stomach and esophagus are being destroyed. Can you really blame the stomach for sending you a signal that it isn’t very happy?

By the way, epithelial cells are what line the urethra as it passes through the prostate. Eating tomatoes in the hopes of reducing prostate cancer is similar to friendly fire—it destroys the cancerous cells and normal cells at the same time. Does destroying your normal and healthy cells sound like a good idea? Not to me. Actually, it sounds very similar to chemotherapy and radiation—trying to kill cancer cells while hoping that the normal cells survive the process. While there is a time and place for that type of approach, I don’t think I’d want to be eating such a potentially cell-destructive substance every day in my food.

Scientists are currently studying tomatine to use as an adjuvant in vaccines, in order to make the vaccine more effective by stimulating a massive immune reaction. The immune reaction happens because the body is reacting to the cell destruction that occurs when tomatine comes in contact with human cells.

Tomatoes also contain tomato lectin (another well-known lectin is gluten) which has been shown to agglutinate human, mouse and sheep erythrocytes—it can cause red blood cells to clump together. Combined together with tomatine, these compounds can cause leaky gut syndrome and potentially be a major issue in autoimmune diseases of all sorts.

For those of you have gone off gluten and you’re wondering why you still have digestive problems, it may be because of tomatoes. Potatoes can be another culprit, as many gluten-free products are filled with potato starch.



1. Famine, Mortality, and Epidemic Disease in the Process of Modernization, by John D. Post © 1976 Economic History Society,

2. Childers NF. Arthritis-Childer’s Diet to Stop It. Nightshades, Aging, and Ill Health, 4th ed. Florida: Horticultural Publications, 1993; 19-21.

3. Ibid.



6. World Health Organization, Toxicological Evaluation of Certain Food Additives and naturally Occuring Toxicants, Thirty-ninth Meeting of the Joint FAO/ WHO Expert Committee on Food Additives (JECFA) WHO Food Additives Series, No 30;

7. Patel B and others. Potato glycoalkaloids adversely affect intestinal permeability and aggravate inflammatory bowel disease. Inflamm Bowel Dis. 2002 Sep;8(5):340-6. PubMed ID: 124796498.

8. Baker D and others. Lesions of potato sprout and extracted potato sprout alkaloid toxicity in Syrian hamsters. J Toxicol Clin Toxicol. 1987;25(3):199-208. PubMed ID: 3612898.

9. Ruseler-van Embden JG and others. Potato tuber proteins efficiently inhibit human faecal proteolytic activity: implications for treatment of peri-anal dermatitis. Eur J Clin Invest. 2004 Apr;34(4):303-11. PubMed ID: 15086363.

10. Friedman M and others. Anticarcinogenic effects of glycoalkaloids from potatoes against human cervical, liver, lymphoma, and stomach cancer cells. J Agric Food Chem. 2005 Jul 27;53(15):6162-9. PubMed ID: 16029012.

11. Masterson JG and others. Anencephaly and potato blight in the Republic of Ireland. Br J Prev Soc Med. 1974 May;28(2):81-4. PubMed ID: 4604097.

12. Galatz LM and others. Nicotine delays tendon-to-bone healing in a rat shoulder model. J Bone Joint Surg Am. 2006 Sep;88(9):2027-34. PubMed ID: 16951120.

13. Galatz LM and others. Delayed repair of tendon to bone injuries leads to decreased biomechanical properties and bone loss. J Orthop Res. 2005 Nov;23(6):1441-7. PubMed ID: 16055296.

14. Razavi R and others. TRPV1+ sensory neurons control beta cell stress and islet inflammation in autoimmune diabetes. Cell. 2006 Dec 15;127(6):1123-35.PMID: 17174891.

15. Keeble J and others. Involvement of transient receptor potential vanilloid 1 in the vascular and hyperalgesic components of joint inflammation. Arthritis Rheum. 2005 Oct;52(10):3248-56. PubMed ID: 16200599.

16. LĂłpez-Carrillo L and others. Chili pepper consumption and gastric cancer in Mexico: a case-control study. Am J Epidemiol. 1994 Feb 1;139(3):263-71. PubMed ID: 8116601.

17. Dömötör A and others. Immunohistochemical distribution of vanilloid receptor, calcitonin-gene related peptide and substance P in gastrointestinal mucosa of patients with different gastrointestinal disorders. Inflammopharmacology. 2005;13(1-3):161-77. PubMed ID: 16259736.

18. Seyama Y and others. Effect of vitamin K2 on experimental calcinosis induced by vitamin D2 in rat soft tissue. Int J Vitam Nutr Res. 1996;66(1):36-8. PubMed ID: 8698544.

19. Tajner-Czopek A and others. Changes in glycoalkaloids content of potatoes destined for consumption (2008) Food Chemistry, 106 (2), pp. 706-711.

20. Boileau TW and others. Prostate carcinogenesis in N-methyl-N-nitrosourea (NMU)- testosterone-treated rats fed tomato powder, lycopene, or energy-restricted diets. J Natl Cancer Inst. 2003 Nov 5;95(21):1578-86.PubMed ID: 14600090.

21. Friedman M and others. Tomatine-containing green tomato extracts inhibit growth of human breast, colon, liver, and stomach cancer cells. J Agric Food Chem. 2009 Jul 8;57(13):5727-33. PubMed ID: 19514731.


This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly journal of the Weston A. Price Foundation, Spring 2010.

About the Author


Comments (37)Add Comment
Incorrect information...
written by Marcia, Apr 19 2014
The author states that calitrol increases calcium absorption from the gut, and then deposits this "extra calcium" in the joints, and that's why nightshades are a problem.

I think that's incorrect. If one is not getting sufficient calcium from the diet, then the calitrol will pull the calcium FROM THE BONES, which then causes the bone spurs, the joint problems. A google or other search will turn up how bone spurs are the result of insufficient calcium, not the other way around.
written by Arlene Cocke, Apr 13 2014
I will try anything for this pain.
I take very little Tylenol, what my GP recommens.
Thank you for a possible relief, naturally.
written by Jennifer Harley, Apr 13 2014
I cut out all nightshades for 30 days after reading some things on here and other sites about how they might be contributing to all the inflammation and the morning stiffness and back pain and leg/feet swelling/inflammation. It was really hard to cut them out completely because they are in EVERYTHING - there is 'potato starch' in many commercial breads. There is tomato paste and tomato powder that flavors nearly all commercial foods. There are peppers and tomatoes in most restaurant foods. Even deli meat has potato starch in it. I cut out everything, including 'natural flavors' and 'spices' and 'food starch.' This meant I really ate very simply, mostly all whole foods that I prepared at home, with a few exceptions. I didn't eat out in a restaurant at all during that month. Well, the 31st day I ate a piece of pizza with tomato sauce and crushed red pepper and my throat swelled up (inside) instantly. I could barely breathe, and the tears were pouring down my face. I LOVE crushed red pepper and previously would put it on everything. I love salsa, I love tomatoes, love potatoes, etc. Anyway, the next few days I felt drugged. I realized that my morning stiffness had returned and I was sluggish and just felt, well, drugged! Like a foggy head and extremely tired all the time. I started eating out again but tried to avoid nightshades generally, at least in their macro form. Then a few weeks later I ate a potato taco with jalopeno salsa and some jalapeno salsa with chips. My stomach hurt afterwards and I felt drugged again for the next few days. Now I avoid tomatoes, potatoes and peppers as much as possible and my friends think I'm just making it all up. It's really frustrating. So it's hard to want to eat out with anyone - if I ask the restaurant to hold the tomatoes, my friends ask me why and when I tell them they said that's not possible, that tomatoes are good for you.
Thank you!
written by Toby B, Apr 02 2014
I am excited to finally find a potential cure to my middle back pain. There is hardly any information out on the net for this type of back pain. It sounds like other people have had success with elimination. I will give it a shot. Again, thank you for posting this information!
written by Emery, Jan 16 2014
Don't forget tobacco smoke. Tobacco is also a nightshade.
written by Sara, Sep 23 2013
Thank you for this. I have attempted this nightshade free diet once for a week and I know it helped. My pain seemed to diminish. Why only a week? I guess I fell to my baser instincts. I've been wary of them since that but just recently I went on a potato salad kick and made it for two parties. I ate potatoes constantly for breakfast lunch etc...guess what. I got jacked up--bad. My joints were popping everywhere. I'm done with them, potatoes especially. It's been 3-4 days with out and there does seem to be an improvement. This article is what I needed. I can't thank you enough for writing this. I just wonder if small amounts of pepper/paprika will ruin the good effects I am seeing. I also wonder if potatoes are worse (have more) that tomatoes in terms of the solanine content.
written by debbie, Sep 19 2013
What about solanine in non-nightshade foods. I have happily eliminated nightshades which I know cause me to have muscle pain. I recently had a painful day after eating artichokes. My google research talks of several foods (artichokes, beets, blueberries) that have solanine in them. Has your research found a problem with these foods?
written by Ian, Sep 02 2013
Interesting! I recently stopped all forms of caffeine and any form of natural sweeteners/fruits/refined sugar. I decided to get some tomatoes and thought it was low glycemic enough and wouldn't be a problem for me. I had one tomato and then found myself wanting to eat every tomato I bought like Golum in the Lord of the Rings. So my experience backs up this article.

I was told I need to remove all forms of caffeine, fruits/sweets, alcohol for a long period of time to recover from severe hypoglycemia, adrenal burnout, low DHEA, with low thyroid to boot. It manifests as emotional/financial instability and bipolar like craziness! I've already experience how awesome life is when I stick with it. The hard part is the uncomfortableness and addiction I have to these things. I was told that what awaits me on the other side of "the forest" of withdrawal is beyond my wildest dreams and "so good"! I want that and keep reminding myself when I want to go eat fruit that real love, confidence, and feeling like myself again is worth the wait!

You are so right
written by Kbeadle, Aug 13 2013
I have great pain when I break my night shade restricted diet. I have AS and this seems to somehow be tied into my sensitivity to night shades. Thanks for the great information.
written by Amy Waczek, Jul 13 2013
This is a great article! Through years of food elimination and several Chronic Fatigue diagnosis, night-shades are the main culprit. Every symptom of my illness is gone with the elimination of nightshades, gluten, soy, dairy and corn. Okay, it's not easy, but nor is living with pain. Thank you for such a technical, yet accessible article.
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written by James Carver, Jun 20 2013
I recently developed Inverse Psoriasis and identified nightshades as a source of pain. The pain increases within 24 hours and last 1-2 days after eating nightshades. Avoiding nightshades makes the psoriasis more tolerable.
written by anon, Jun 09 2013
I get tired and I get severe brainfog from eating potatoes. I've been almost addicted to potatoes all my life, maybe it has something to do with the toxic compounds in it. It has always been my favorite food (except for fast food), I've even had dreams and wrote stories about potatoes in school. Potato chips is the only fast food I have major difficulty in giving up.

Nightshades and Appendicitis Pain
written by Cassie, May 28 2013
I finally worked out why I had a pain in my appendix for the last couple of years. Nightshades! I eliminated them and the pain went. Start eating them again and the pain comes back. Wonderful as it was just luck I worked it out
nightshade reaction
written by Priscilla Newcomb, Apr 24 2013
I experienced a toxic response to Cipro, one of the quinolone antibiotics (Levaquin, Avelox also in this class). I was unable to walk re severe tendonitis and joint pain. I had significant relief (75-80%) of joint pain and tendonitis within 48 hours of eliminating nightshades.
written by George Marks, Mar 22 2013
I have been eating a healthy, whole foods diet for over three years now. Just eliminating vegetable oils, grains, and processed foods from my diet has made a huge change in every other area of my life.

But after several self-experiments where I avoided nightshades for long periods and then reintroduced them (an experiment I've done several times now), I can confirm that the results are exactly as you report in this article. It seems that potatoes are the worst for stiffness and random achy joints. Other nightshades (esp. fresh organic tomatoes) seem to cause slightly different symptoms in me, including itchy red patches on various areas of my skin, and red bumps with pustules.

I wonder if anyone has ever heard of fresh garlic cloves or yellow onions causing similar symptoms in some people? I ask because this week I had both achy joints and red itchy skin patches, but the only thing I can think of that changed in my diet was that I ate chicken that was roasted in onions and garlic.

Thanks for this valuable information! It's so sad to know how many people are suffering and have no idea why, and are not getting any help or relief from most of the medical community.
written by Juliana Limones, Feb 06 2013
I just found out that I have a high level of solanine which is causing my back pain. In disbelief I have been doing a lot of research on the subject and getting very frustrated since being of Hispanic and European descent my diet is largely based on tomatoes, potatoes and PEPPERS. Just as I was coming to terms about what I must do, someone in the "health" field sent me this article contradicting EVERYTHING I read!!!
Who do I believe???
could touching a night shade cause pain?
written by Marielle, Feb 05 2013
Hello. I, as well, get joint pain from eating night shades. And like many, got my life back when I found out! Absolutely fantastic really. But the other day, I picked up a red pepper (for my kids) and a few seconds later I had shooting pain doing down my arm. Incredible. My daughter saw the pain in my face and asked me what was wrong. I smiled. It came and went within seconds. But could it be? I just dont believe it! Do you think it could be psychological? Has anyone experienced this?
Thanks for your help.
Nightshade questions
written by Kay M., Dec 14 2012

Thank you for the great information on nightshades. About one year ago, I developed immediate and delayed food allergies to dairy, wheat, eggs, and a host of others. (Note: I have been on a whole foods pure diet, no sugar for about 3 years). After removing the allergen foods from my diet and eating clean for a year, I was still not feeling well. Anxiety, stiffness, popping in my joints, feeling unsettled, bloating, etc. I've been keeping a food diary lately and noticed that I have been eating a good amount of peppers, potatoes, and tomato sauce, along with paprika and spices. I have been really craving potato chips for about 6 months and was eating them regularly - not my normal eating habit, so it was strange. (My nutritionist said that it was fine as long as they had sea salt and olive oil - go figure). I was wondering if anyone else has had weird anxiety and tingling in their face or body from this? I am also wondering if anyone knows how long it takes for the toxins to leave your body after one stops consuming any of the nightshade foods? Is there a vitamin that can help to detox from this as well? Thank you again!!
Nightshade allergy
written by G Bennett, Dec 10 2012
In 1997 (a nurse, age 46 and in good health), I was almost in a wheelchair due to sudden onset of arthritis in all joints and severe pain in my whole body. For three months I saw doctors who had no idea what happened to me and I studied on the internet to diagnose myself. It finally became clear that I was allergic to solanine in the nightshades. If a restaurant lets a tomato touch my salad but then removes it when noticing that I requested no tomatoes touch my food, and I eat the salad, within 20 minutes my pain and joint swelling starts. I believe if I ate a potato I would be disabled for a couple of months. Once exposed, it takes about 2 months for my symptoms to leave. I will do anything to avoid the nightshades and have for 15 years. I'm just grateful that I learned years ago what I had to avoid. I believe that many of our bedbound residents in nursing homes could be well if someone knew to take them off nightshades. The lack of knowledge of this subject by the general public is astounding. Thanks to all for sharing the information with others.
written by Siobhan Richardson, Nov 03 2012
Thank you for a tremendously informative article on nightshades! I have an "allergy" to nightshades (ie. I produce no anti-toxins for them), and it's rather difficult to find information. I am starting to collect information in one place, including recipes and substitutions:
I'm particularly interested if you have a list of peppers that are not nightshades. I know they exists, but it is proving to be a bit a of process to find them.
Thank you again. It's great to have good information, as well as your suggestions for treatment.
Can nightshades be okay if grown differently?
written by Salem, Sep 17 2012
So, if it is exposure to sun that creates the issues with nightshade plants, is there a way to grow & harvest these plants with little or no exposure to the sun? I know plants need sunlight to grow, but would it be possible to avoid issues with potatoes if they were harvested at night (for example)? Should everyone avoid nightshades or just those that are sensitive to them? In order to have pain reduced (if a person is sensitive to nightshades), would it work at all to reduce the intake of these or would they need to completely avoid them?
written by Tel Tofflemire, May 28 2012
Thanks so much for this valuable information Neinah. I used to know all this then went more mainstream...Duh !
Thanks again, I'll try to sty on the right track. I have many of the issues you wright. & I Love peppers of all kinds ?
Also potatoes. This is all about the way I live.. Thanks so much for sharing Gravett Smiths papers.
Tel Tofflemire
written by Miriam Katz, Apr 23 2012
I am a nutritionist working at The Jwalan Muktika School for Illumination in Whitefish, Montana. We don't recommend eating nightshades because of what was mentioned in the article. I am excited about the article. It has a lot of valuable information. I learned a lot and will pass it on to my students and clients. Thank you for that.

I have coauthored a cookbook with the school and the recipes are gluten , dairy, sugar and nightshade free.
written by James Benson, Apr 13 2012
I have been suffering from insomnia, low back and intermittent severe joint pain for years without being able to localize a cause. Yesterday, I went to a new doctor and he suggested that maybe I am suffering from nightshade toxicity and suggested removing them from my diet. Being a vegan, it is hard to remove all of these that I eat daily, but I am going to try. If there is a cookbook out there, I would love to know about it.
written by Elizabeth Parashis, Mar 26 2012
Why would you recommend a product that contains soy lecithin? Also tuna and skipjack which have heavy metals?

Other Ingredients: Sunflower oil, gelatin, glycerin, water, yellow beeswax, carob extract, soy lecithin, zinc oxide.
written by Marilyn, Feb 24 2012
great article thanks
written by Marilyn, Feb 24 2012
I have had udiagnosable various illness symptoms most of my life. At certain times these things were life threatening. After eliminating glutens and nightshades every adverse condition disappeared. My doctors (those dummies) were shocked but of course happy. It is sad that most conventional doctors think the DASH diet is a great idea and that a diet of grassfed grassfinished beef, lamb, bison, pastured eggs etc and nightshade free veggies and fruits is going to cause heart disease. Their diet reccommnedaitons are loaded with gluten and nightshades, does not contain healthy fats, does not contain enough fat for normal osmotic pressure in the blood in veins returning blood to the heart--which causes heart failure and also varicose veins---It seems as though the doctors do not fully understand how the entire body works---in any great biochemical detain and definatley know nothing baout nutrition. By the way the AMA has changed the Hippocratic oath so that it no longer includes "Let food be thy medicine"
Thank you.
written by Syntk, Nov 03 2011
Thank you for this article on nightshades. I will certainly forward it along. I've been nightshade free (except when it sneaks into me via restaurant food, in spite of my best efforts to question servers and eat carefully) for more than 5 years now, and it has changed my life. I've had joint pain since I was a kid, and a whole host of other health issues as well. Giving up nightshades eliminated at least 95% of all my health issues! I would have NEVER thought I had a problem with nightshades, as they were my favorite foods my whole life. I craved them, enjoyed them, and what could be healthier than eating out of grandma's garden? I loved healthy food and ate a mostly vegetable diet. I was devastated when the very thorough elimination diet my doctor put me on yielded the results on nightshades. I didn't know how I could live without tomato, peppers, potatoes and especially eggplant! I can tell you it was a sacrifice, a true sacrifice for me, and it was WORTH IT! Now that I'm so many years out, I occasionally eat potatoes, but when I start getting sore, I avoid them, too. I avoid the others like they were poison (they are!). I urge everyone to try this diet. It will help with so much, not just with chronic pain, but with all kinds of things!
Holistic Health Practitioner
written by Marilynn Freeman, Apr 11 2011
Thanks for one of the most comprehensive articles I've seen on the subject. I can't wait to start the 6-week trial, which I'm sure will prove to be very illuminating! Great work!
written by sheri, Dec 16 2010
I have suffered with chronic neck pain and shoulder joint pain for the past 3 years. The pain is so intense it wakes me up several times a night. I have tried physical therapy, chiropractic care, acupuncture, estrogen therapy, and finally an epidural. My pain mysteriously disappears some days, but comes back all to soon. All my life I have eaten large amounts of tomatoes, potatoes,artichokes,chile peppers, and i recently added eggplant to my diet. When I did not respond to the acupuncture as expected my acupuncturist suggested maybe I have a nightshade intolerance. I could not imagine that eating these "healthy foods, oould cause such problems. Last year i even suffered with an autoimmune disease which I was fortunate enough to get over. Now, I wonder.....could nightshades be causing all this pain and suffering? I will try the elimation diet and keep you posted.
written by Elena Yates, Nov 04 2010
I would really appreciate if you could recommend a good cookbook which is free from nightshade ingredients. I find it very difficult to avoid pepers and tomatoes. Many thanks

with gratitude
written by amy_lifewithsoul, Oct 09 2010
Thank you for shedding some light on this for us! I have tested the theory and I am glad to say that I have found the culprit for my 10 year back pain. Unreal. Unreal that it is not more widely known. Kind Regards, Amy
written by Anne Hoelz, Sep 15 2010
a lesser known effect of nightshade foods is benign myoclonic seizures. Not proven by the western medical community . . . I can barely get them to even consider the idea . . . but my son is living proof. What's even more amazing is that he has Down Syndrome. All of his delays are blamed on Down Syndrome . . . yet when we eliminated the nightshades, not only did his seizures stop, but his cognitive & motor development took off at a phenomenal rate! We think that nightshades may have something to do with the dvelopmental delays as well but the only way to find out for sure is wait and see. I'm sure not going to re-introduce nightshades to find out if his cognitive development stops again!! I wish more people would just TRY eliminating nightshades from their diet. Just try it, it doesn't cost anything.
written by Veronica Hayduk, Jun 02 2010
As a naturopathic doctor myself I ask my patients to avoid nightshades for more than just pain relief. I see a lot of challenges women face with hormone balancing and some basic food changes make huge differences. I tend to see that the ones that whine the greatest about not eating tomatoes or potatoes are the one most sensitive to them. Heck, it's easy enough to try and best of all, no money needed to see how well not eating nightshades works! It can be the magic fix you have been searching for.
Nutrition Consultant
written by Laura Knoff, B.Sc., Apr 11 2010
I too have noticed that I am very sensitive to nightshades, even in trace amounts. After having not eaten nightshades generally and potatoes specifically for many months, I ate some vegetables that had contacted potatoes at one dinner and spent the next 24 hours with my right wrist in agony. The pain disappeared in 24 hours. I would not have understood the cause if it did not happen again at a buffet. I ate some zucchini that had been roasted with eggplant and peppers and again I had extreme wrist pain for 24 hours. I am convinced to not have these foods in my diet ever again. I tell my clients to avoid them for at least 3 months then reintroduce them and monitor their results. Glad to hear others are discovering the cause of their distress.
Nightshades/Food features
written by Linda Douglas, Mar 31 2010
As a patient of Garrett Smith's I am commenting to say I'm glad you got this out on the web Garrett. Much success to you. P.S. Cutting nightshades out of my diet helped a great deal with cronic pain!!

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Last Updated on Monday, 31 December 2012 19:35