What’s a nightshade?

Nightshades are a fascinating and important plant family, the Solanaceae. Major nightshades that produce food are potatoes, tomatoes, peppers, and eggplants. Less common family members include goji berries, the pepino melon, ground cherries, and tomatillos. The increasingly popular herb ashwagandha (Withania somnifera)—AKA Indian ginseng, poison gooseberry, or winter cherry—is also a nightshade.

Potatoes, tomatoes, peppers were all domesticated in Central and South America, along with another important nightshade: tobacco. When these nightshades moved to Europe and Asia they profoundly influenced both regional cuisines and agricultural economies, helping to shape the contours of the modern world as part of a phenomenon called the Columbian Exchange. It’s hard to find a contemporary cuisine where nightshades aren’t heavily represented.

The nightshade name comes from deadly nightshade, or belladonna, a poison known at least as far back as the classical Greeks. Like all plants, nightshades produce an amazing array of chemical compounds. These are thought to have evolved to discourage animals from nibbling. Tobacco, another famous nightshade, produces another notorious chemical: nicotine. Other notable nightshade compounds include tropane alkaloids such as atropine (from mandrake, used as early as the fourth century BC) and scopolamine (from henbane, documented in the first century AD).

The nightshades that most of us eat every day also produce poisonous glycoalkaloids. Potatoes are monitored for levels of the alkaloids solanine and chaconine. For a long time we thought that these were related to the greening of potatoes, and that’s why you were advised to remove sprouts and any green peels from potatoes. Research has put that precaution in doubt, but it is clear that improper storage and handling can increase glycoalkaloid levels.

That doesn’t mean these plants are necessarily poisonous. All plants contain many things that, at a high enough dose, are poisonous. It’s the dose that makes the difference. Nicotine is the most infamous chemical of nightshade origin, and while it’s clearly recognized as a poison—it can kill you quickly, not just over decades—it’s also still regularly consumed as a stimulant. Too much scopolamine or atropine could kill you, a smaller dose may make you hallucinate, while smaller doses still may have medical benefit.

Isn’t okra a nightshade?

Okra is not a nightshade. I’ve seen this reported both online and in print, but it is not true. Okra is a member of the mallow family (Malvaceae).

What is the No Nightshade Kitchen?

The primary goal of this site is to create an online resource for people trying to avoid nightshades in their diet. Some people avoid just nightshades, while others may be following a regimen (paleo, FODMAP, autoimmune protocol) where some or all nightshades are discouraged. This site will include recipes and menu planning ideas, and lots of experiments attempting to replace or mimic some of the uniquely intense nightshade flavors. There will be cuisine reviews and product reviews. Because I’m interested in why nightshades cause problems for some people, I’ll also keep an eye on news about the science of food allergies and food sensitivity. I’ll also try to keep tabs on related stories about diet, inflammation, and the fascinating research on the role of your gut flora in this complex equation. And because I’ve found it very difficult to avoid nightshades in restaurants, and in certain prepared foods (meats, sausages, broths, condiments, common snack foods), there will be a three-pronged advocacy component as well to help you in educating and lobbying local restaurateurs, food companies, and policy makers.

What is nightshade sensitivity?

Through dietary experimentation, some people have determined that nightshades in their diet negatively affect some aspect of their health.

What kind of health problems can nightshades cause?

Nightshade sensitivity is poorly understood and poorly researched. That means that most of what we have is anecdotal evidence—in other words, personal stories. The most obvious are tummy troubles: cramping, pain, a sour stomach, GERD, diarrhea, constipation, and blood in the stool. More general symptoms include joint pain and puffiness—what some people, including some doctors, have identified as inflammation. Other people have reported cognitive symptoms: headaches, depression, anxiety, and cognitive impairment.

Is sensitivity the same as a food allergy?

Food allergy and food sensitivity are not the same thing, although the lingo (allergy, sensitivity, intolerance) is used somewhat inconsistently in some of the scientific literature. In food allergy minute amounts of the offending food can trigger a dangerous immune system reaction called anaphylaxis. People with potato allergies, for example, need to worry about the fact that yeast and B vitamins can both be cultured on potato products. Food sensitivity may or may not engage other elements of the human immune system. It’s been observed that many people with food sensitivities can handle trace or even occasional doses of the offending food without significant health consequences, though some people are quite sensitive. But, confusingly, allergy is also called hypersensitivity. Intolerance is when your body can’t process some ingredients in a food, like lactose.

Isn’t nightshade sensitivity kind of a quackish idea?

Yes and no. I’ve read some pretty quackish ideas about nightshade sensitivity, and I’ve also read about nightshade sensitivity on some websites with a dubious relationship to scientific reality. No definitive scientific explanation exists for nightshade sensitivity. I believe that it’s hard to recognize and that science hasn’t looked very hard, partly because we haven’t had the tools and concepts necessary to decipher it. A portion of this website is dedicated to understanding the science of how nightshade sensitivity might work and why it can’t be ruled out.

How do I find out if I’m sensitive to nightshades?

Discovering food allergies and sensitivities can be extremely difficult. Even if you cook everything from scratch, our diets are very complex. The more processed and prepared foods you consume, the more tangled the discovery process is. Medical science can help diagnose some food sensitivities—celiac tests are reliable, and sometimes a food allergy will show up in blood or skin tests. But not always. A low-grade allergy could feel like a sensitivity.

There is no laboratory test that can diagnose a nightshade sensitivity. The gold standard is how you feel when you eat a food compared to when you don’t. The systematic way to do this is through an elimination diet.

What’s the difference between nitrates and nightshades?

Not many people know what nightshades are, but they’ve heard of nitrates. So when you’re educating people about nightshade sensitivity you need to make sure they don’t think that you said NITRATES. Nitrates are chemicals commonly used in the preservation of certain kinds of meats (such as bacon, sausage, and hams) and also in wines and dried fruits. It’s even easier to confuse nitrates and nightshades because many people try to avoid nitrates because of perceived health consequences.

Just what kind of cook are you? How do we know these recipes work?

As food blogs go, the kitchen side of this operation is low key. I’ve worked as a cook before, but that was long ago. I don’t have recipe testers, or a test kitchen apart from my own kitchen. I don’t send the recipes out to someone else to try to make. (Volunteers anyone?) But most everything on here has been made at least a half dozen times, and gets fed to a wide variety of friends and family. And I don’t often lack for guests when I invite people for a tasting.

You’re using footnotes? On a food website?

Yeah, it’s a little crazy. I’m not going to do it everywhere, particularly on the recipe side of things. I am using them where the knowledge is particularly obscure, or where it has been hard won. Popular nutrition books and websites repeat a lot of generalizations and also have a tendency to repeat some accepted wisdom as truth. As a science writer, trying to run these questionable nuggets down has driven me to distraction. Sometimes they’re easy to prove or disprove, or to at least distinguish opinion from fact. But sometimes you have to follow scant breadcrumbs, and in those cases I believe in sharing my work. My training as a journalist includes a belief in transparency. If you know where I found my information it should assist others in the larger conversations surrounding diet and health, and may help readers better understand their own dietary issues.

I have a recipe to share. How can I do that?

In some future versions of this site, there is a forum where that might happen. In the meantime, you can email me here and we can talk about it.

I’d like you to look into this [product/cuisine/ingredient/health claim]

Email me here and we can talk about it.

Are you making any money here?

Not yet. While this is a personal passion and a service mission, this is not just a hobby site. I’ve been a freelance writer for all of my adult life. I’ve now spent thousands of hours developing recipes and doing research into food systems, products, and the science of food sensitivity. I have no plans to charge for the content on this site, but I ultimately hope to find ways to make the site pay for itself, whether through advertising, affiliate links, or related publishing and other business opportunities. Like many people in the publishing world today, I’m not entirely certain how that’s going to work out. I pledge to be transparent about any financial interests that may affect my objectivity, and encourage you to ask questions if you have concerns.

Why is commenting moderated?

One simple reason: there be trolls! I don’t anticipate needing to use a heavy hand here, but we’ve all seen what can happen without it. As a science journalist who has seen a lot of questionable health claims on the web, I’m inclined to keep a tight reign on content posted here. My goal is a helpful and easy to use resource.

Is a diet without nightshades healthy?

Great question. Stay tuned for more thinking and reporting on this topic.

What will my doctor think about this?

I’m not a doctor, and the content on this site does not constitute medical advice. Before embarking on a radical change in diet you should consult with your physician. At that point it may get complicated. Not all doctors are well versed in food sensitivity, and physicians have good reason to be skeptical of fad diets and any health advice you found on the internet. To help deal with this, read up on elimination diets, and be patient in your conversations with your doctor about why you want to do this. In rare circumstances you may need to consult another physician, but I believe if you engage honestly with your caregiver you’ll be able to devise a plan that satisfies both of you.

Does cooking reduce nightshade sensitivity reactions?

Because we don’t know what precisely causes the reactions, this question can’t be reliably answered. We do know that potatoes are rarely eaten raw, so if they do bother you the answer is probably no. In studies of cooked potatoes, tomatoes, and eggplants the glycoalkaloids most commonly suspected of causing sensitivity reactions are not significantly reduced.1

If You Are Nightshade Sensitive, Are All Nightshades Bad?

The short answer is we don’t know. Because we don’t know what precisely causes the reactions, this question can’t be reliably answered. Many people with nightshade sensitivity lump all of these plants together. As documented in this essay, repeated experience and exposure has shown us that our bodies respond similarly. It doesn’t mean we understand how or why.

If your symptoms of nightshade sensitivity and your love of goji berries or tomatillos is strong enough, you may choose to test this on yourself. Or perhaps you’re the kind of person who can have nightshades occasionally, and you can eat them. Autoimmune diseases sometimes can be hypersensitive to triggers. People for whom nightshades appear to trigger autoimmune disease progression or other longer term effects often choose to avoid all nightshades altogether.

Who runs this place?

That would be me. Also me.

  1. “Chemistry and Anticarcinogenic Mechanisms of Glycoalkaloids Produced by Eggplants, Potatoes, and Tomatoes” https://doi.org/10.1021/acs.jafc.5b00818 []


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