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What is a nightshade? The name itself seems exotic, like a ghost or some kind of mystical entity of the dark. You may have heard of the "deadly nightshade", Atropa belladonna, a beautiful flowering plant sometimes refined and used in medicine but which can be poisonous and, as the name suggests, very deadly. In fact, some cultures historically have viewed all nightshades as poisons and though perhaps valuable for medicinal purposes, would never be a part of nutrition or included in the diet. But you might be surprised to find that the reality is you probably encounter nightshades every day, and very likely eat them at many meals. Like the mysterious name, much of what nightshades are has been clouded in mystery and few people are aware of the pros and cons that nightshades may have on their nutrition and overall health.

Understanding nightshades.

Nightshades can be very nutritionally beneficial. But they also can have a dire effect on health for some people. It is a very diverse family of plants, with over 2,500 species. Perhaps a good way to get an idea of this is with a list of some common nightshades you have, no doubt, encountered. Nightshades include: Potatoes, hot and sweet peppers (not including black/white condiment pepper and peppercorns), eggplant, pimentos, tomatillos, cherries, garden huckleberries and blueberries, goji berries, artichokes, tomatoes, paprika, and cayenne peppers.

Nightshades have been consumed all over the world for thousands of years. In fact, they have even been the staple diet in some cultures and communities. Everyone has heard of the Irish potato famine. Potatoes, being high in carbohydrates and a hardy root vegetable, were an easy way to provide the daily caloric needs of that community. When the crops began to fail, the consequences were tragic. Italian food has long used tomato based sauces. Mexican, Spanish and Indian food often feature hot chili peppers. Everyday restaurants all over the world toss tomatoes and bell peppers into their salads. So does this mean that nightshades are an innocuous and wholesome food? Often yes, but for some, perhaps not.

To understand the real complexity of nightshades, consider this: Tobacco, an addictive and dangerous plant when smoked, is a nightshade. Is it unique? Well, a nicotine addict, in a pinch, could smoke tomato leaves and curb the craving as they contain, in much smaller quantities, the same chemicals the addict is seeking. Clearly there is a powerful drug effect in some nightshades, yet many are foods we eat all the time. So what is it that connects tobacco, tomatoes, potatoes and a deadly poisonous flower? The thing they all have in common, in varying degrees, is a chemical component called an alkaloid. And it is in these alkaloids where the problem may lie for some people.

For most people, including some portion of nightshade foods in the diet poses no problem and there are no adverse consequences. If that were not true, nightshades would not be so popular and so ubiquitous in cuisines across the globe. But the jury is still out regarding some of the possible problems nightshades, and specifically the chemical they contain, can pose for certain portions of the population. More research is needed, and there are currently no hard and fast rules, but there is enough evidence and enough study at this point that perhaps a word of caution should be heeded by some.

So who should be concerned and why?

Again, there needs to be more clinical study to come up with a prescriptive course of action and more data to back that up, but there does exist both a large amount of anecdotal evidence, as well as medical data to indicate that people who suffer from certain types of arthritis, particularly osteoarthritis, ankylosing spondylitis (AS) and rheumatoid arthritis, and to a lesser degree people with other joint problems like gout, can experience significant adverse reactions. These conditions are all inflammatory in nature, and can be aggravated by substances that cause flare-ups in inflammation. Some research has shown that the alkaloids in food nightshades can cause depositing of calcium in soft tissue.

With diseases like rheumatoid arthritis and particularly AS, this is a serious problem, since it can exacerbate the joint problems experienced and over time can make the condition worse. With rheumatoid arthritis, a flare up causes fluid in the joints and consequent joint damage. Ankylosing spondylitis is characterized by the build of calcium in joints, particularly the back and hip. In these cases, alkaloids that cause calcium to deposit in joints contributes to the problem and some have reported that there is a direct connection between eating nightshades and painful episodes of the condition. These alkaloids can cause inflammation and altered mineral status in the joints causing not just pain, but increasing long-term damage. For these people it is sometimes advised to consider limiting, or even eliminating, nightshades from the diet, since these diseases are progressive and avoiding flare-ups is therefore very important in averting continued and increased damage, pain and immobility.

There is also speculation that, aside from those with such conditions, a portion of the population is simply very sensitive to these alkaloids, and can have symptoms that mimic arthritis when too many nightshades are consumed. In fact, there has been medical speculation that some cases of mild arthritis are actually misdiagnosed reactions to excessive nightshade consumption. In such cases, a period of abstinence from nightshades may be used as a test, in which patients avoid all nightshades for three months to determine if the problem is dietary rather than some other ongoing problem.

So are nightshades bad?

No, of course not! Many nightshade foods are nutritious, delicious and a safe part of most people's daily diet. However, much is not known about the alkaloids they contain and there is definite evidence that for some they may pose a real problem. As with all the foods we eat, it is important for individuals to be aware, to listen to their bodies and to adapt as needed. Just as many people can eat dairy products with no problem at all, others have varying levels of lactose intolerance that can cause problems from mild to severe. Likewise, for a lot of people, glutens pose no problem, but there are those with gluten sensitivity, or in severe cases celiac disease, for whom glutens must be avoided in the diet. That doesn't mean that dairy or glutens are intrinsically or universally bad, or that all people should avoid them, just that those who are effected need to be aware.

So if you feel fine and love nightshade foods, it would be silly to vilify a group of foods that are often nutritious and good for you in so many ways. But for those people who have the conditions mentioned above, it might be worth considering a test in which you cut back on the nightshades, or eliminate them, and see if that may help. Particularly with some of the more severe cases, in which the condition is debilitating and progressive, knowledge is power and anything you can do that may help the situation is worth some serious thought.

So what should we do?

If you are concerned, but don't want to cut nightshades out altogether, cooking the food thoroughly decreases the alkaloid content by up to 50% so avoid eating them raw. Also, examine potatoes for green and sprouted spots as these indicate high levels of alkaloids. Keep track of what you are eating and how it affects you over time. Vary nightshades in the diet and see if that has any impact on how you feel. If you find that you feel better when you eat less of these food types, then you know you should probably limit your intake.

For those with serious conditions that may be impacted by nightshades, or whose health problems are progressive and causing serious pain or immobility, talk to your doctor, of course, but consider a long test in which you eliminate nightshades, perhaps three to six months. Track how you feel and how your condition responds. Of course there are many factors that can contribute, and it is very important to have appropriate medical care and a doctor's supervision, but on a day to day basis we are all in control of what we eat. As long as you have a balanced, complete and diverse diet, it is unlikely that eliminating nightshades would harm you, and perhaps you may experience some improvement.

Remember, for most people nightshades are perfectly safe to eat, part of a balanced diet and often are a favorite for many people. It would be irrational to give up potatoes if they are your favorite food and you are perfectly healthy and comfortable eating them. Similarly, for many people hot food really is the spice of life, and it would be sad if they gave up their chili peppers for no good reason! Just listen to your body, eat a balanced diet, and if you have a serious condition, or see a reaction to these types of foods, talk to your doctor and consider what dietary steps make sense for you. Knowledge is indeed empowering, but it is important not to misapply it or to find a problem where there is none. For most of us, nightshades are a wonderful part of what we eat, and there is no need to be concerned, so go ahead and enjoy them!

By Louise at Grace 

NOTE: The above article is meant to provide information and to encourage a healthy awareness of food and how it may affect each of us differently. It is not intended as medical advice. Please see a medical professional if you feel you have a serious condition.


By: John
On: 05/01/2014 05:29:50
Truly enlightening article and I thank you for it. I had mentioned this in a comment on another article on the Grace Cuisine blogs - but didn't actually know much about it. I have several people in my life with arthritis, and am a candidate for it myself if genetics plays a role, so always looking for info on what I can do. A nice surprise to find an article on it here. I had heard this, that something about nightshades played some kind of role, but didn't know that it could have a big impact in that way. I am going to have my dad do the sic month challenge the article mentions, and see if that helps. It will be tough, since potatoes are his go-to, feel good food of choice, but anyone who has dealt with severe arthritis knows that giving up a food is a small sacrifice if it will cut down on the pain and maybe slow the progress, or at least not speed it up! Again thanks!
By: Anna
On: 05/02/2014 09:49:05
Great article! I know people with arthritis and I think a lot of people don't realize that it is so progressive and that flare ups do actual damage that you can't reverse. So it is important to avoid it. But then people don't kow what causes it, so what can you do? I think that there is a lot of interplay between food and various illnesses, particularly any autoimmune disease ( which some forms of arthritis are) and so it is good to look at the connections between food types and health conditions. But you never hear this warning. So thanks - helpful info!
By: Catherine
On: 05/03/2014 11:31:40
Yes, more study is needed. I hope some doctors see this article and get to work on that. Till then though, I agree with the other 2 comments, and with the article. Arthritis is really nasty, especially the types that progress and cause damage. Better safe than sorry. I know nightshades are awesome - and I would hate to give up some of them, but there are so many types of food in the world. If in doubt, leave it out, that is my motto when it comes to stuff like this. Good article!
By: Mike Grant
On: 05/09/2014 11:39:52
I had no idea what a nightshade was. I had heard that term before, but never even thought there was a connection between things like tobacco and tomotoes. It's a little scary actually. I sometimes get joint problems, though I haven't been diagnosed with arthritis, and never know what it is. I take joint supplements to help. Maybe I should do the little test they mentionin the article and see if it helps. Food for thought. GRACE CUISINE: Hi Mike. Thanks for the comment. If you decide to give it a go make sure to report back, we'd be interested to see how you get on. Good luck!
By: Mike Grant
On: 05/10/2014 08:25:52
Hi Grace Cuisine- I will do that! I actually just started today. NO nightshades for me for the next 3 months! It will be tough, but I am going to try it and see if that helps with the joint problems I seem to get from time to time. I will let you know how it goes. It will be an interesting little study.
By: Jasper M.
On: 05/11/2014 19:32:40
I am a retired doctor and did some work with arthritis patience many years ago. It is very important that they be aware of how food can impact the condition. Nightshades really do cause some problems for some patients and I always suggested they should treat it as though they have a food allergy. There really does need to be more work done on alkaloids. Great article!
By: Kevin
On: 05/17/2014 14:30:55
Helpful stuff to know. I have suffered with mild arthritis for years. I have tried exercise, yoga, and every kind of medicine in the book. I currently take anti-inflamatories and pain killers on the bad days, along with a number of joint support supplements. If cutting back on a certain kind of food would help, that is easy! I will think twice next time I go for a super hot curries with potatoes! If it makes the pain worse - not worth it. Thanks for the info!
By: Matt
On: 08/25/2014 23:42:57
The thought of giving up potatoes is almost enough to bring me to tears- nope, can't do it. But there is arthritis in my family. I will see how I go, I guess. It's easy to say never when you aren't in any pain. At least if I do end up developing arthiritis, I know about this now and can keep an eye on it and talk to my doc about it. Till I do, I plan to eat as many potatos and hot chilli peppers as i want - just in case I ever have to give them up - may as well indulge while I can!
By: Steve
On: 09/12/2014 17:27:09
Its name isn't a nice name. Why do they name all these foods something that is scary. Why is it named that anyhow. I eat potatoes almost all the time. I hope it's ok to eat so many. I don't think I have the thing it talked about though the ankle thing. AS. Lots of things to know about when I eat. I am glad I know this now. I will sometimes have other things then potatoes. I like pretzels so that is ok instead of chips.
By: Greetings from my planet
On: 09/13/2014 20:02:28
Steve, do not be afraid. It will be ok.. It sounds like you are fine and can have your chips at will... It is just talking to people with extreme conditions.

Ok, so I love all these foods. I don't have arthritis, though maybe one day I will - who knows. I am young now so plan to eat my fries, my super hot chilli sauce that burns from beginning to end and puts hair on a man's chest, as my deal old dad would say, and don't even think about taking away my potato chips cuz thems fightin words! I have spoken. MTFBWY and LLAP!!!
By: Steve
On: 09/14/2014 15:54:56
Hi Greetings from planet, thank you for your kind words. I like my chips a lot and don't want to not eat them. I am glad to think Im not making problems for my health. I make sure I eat good each day and I make sure I have all food groups. I like potatoes a lot too and chips are my favorite snack. I like mashed potatoes best of all and my mom makes that really good too. I like that I can eat these. I hope you don't get arthtrist like you said and will hope you don;t in your future. GRACE CUISINE: Welcome Steve, can we recommend if you ever wish to follow one of our recipes on here, you stick to the salads. We don't want your mum returning home one day to find the house burned down.
By: Steve
On: 09/14/2014 16:20:35
Thank you Grace Cuisine. I think your right. My mom lets me help a lot in the kitchen. You are right and my mom says that too that I shouldnt try to make stuff all on my own. I like to make food but my mom says when Im older I can make it all on my own and once I made macoroni and cheese by myself and didn't have any help but my dad was in the kitchen watching but didn't help so it was on my own. It got a little bit burned on the bottom but it was still good to eat and i ate lotsof it because I like cheese a lot. I could make salad really good i think and don't wnat to burn stuff down so thats pretty good idea you have. I like this message board a lot and it has good ideas.
By: James Robson
On: 01/20/2015 21:03:08
I gave up all nightshades (including quitting smoking - yay me!) 6 years ago. I have severe arthritis and it can be crippling. I don't want to claim a magic cure, and I still have arthritis, but I am pretty sure that the nightshades were making it worse, and it is more manageable now. Like the post says, it's probably fine for most people but if you have arthritis, you really should try the test suggested

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