Aidan:
Hello and welcome to the Ideal Nutrition Podcast. My name is Aidan Muir and I’m here with my co-host, Leah Higl. And this is episode 188 where we’re going to be talking about whether you should avoid nightshade vegetables or not. And the reason we’re talking about it is just because it’s just a common question, to be honest. It’s just something that comes up a lot. Specifically, I’d say mostly in relation to autoimmune conditions, but there is also just a lot of talk about it in general. So we will go through and answer this question.
Leah:
Starting with what nightshade vegetables are. So obviously they are a group of vegetables, but specifically from a certain type of family. Some of these plants are not considered edible while others obviously are. So all nightshades contain what we call alkaloids. One of these is called solanine which is something that is toxic when consumed in large amounts, but okay in minimal amounts and common examples of nightshade vegetables are potato, eggplant, tomato and capsicum.
Aidan:
The reason people propose avoiding them typically linked back to those components such as solanine. People often talk about how they can contribute to inflammation and joint pain and they’re proposed to contribute to stuff like leaky gut as well. So that’s part of why also autoimmune conditions in particular are anecdotally linked with nightshades. And some people talking about this will act as if it is the cause of all problems, but other people do have a much more nuanced take proposing things such as maybe it’s only relevant for certain people and maybe it’s only relevant for people who might have allergies or intolerances to nightshades specifically.
Leah:
Yeah, I wonder actually how much crossover this does have with histamine, which we did an episode on a couple of weeks ago now.
Aidan:
Yeah.
Leah:
Just given that there obviously is crossover between like the tomato eggplant, et cetera. So looking a little bit further and kind of maybe some general flaws in this thinking. Mechanistically, we can look at some of that stuff. So solanine does not appear to be harmful at a population level when consumed in quote on quote normal amounts. For example, regular potatoes do contain solanine, but the amount is typically super insignificant and not an issue. But if a potato is green or a tomato is very unripe, it can contain a lot more of this compound which could become more of an issue.
In many cases, people can get just GI issues from eating these things in larger amounts, although there are multiple variables that could potentially be at play, like histamine for example. At a population level, these vegetables do not appear to be linked with inflammation overall.
Aidan:
With inflammatory bowel disease and rheumatoid arthritis, there are a few cases where people have pointed to research that’s not in humans, so it’s in animals, but pointed to the fact that in this research, there can be a potential link, but it’s arguably a stretch to apply that too strongly, particularly because we see this a lot in animal research and also when dosages may not be specifically relevant to humans, because as you touched on Leah, like there are these doses just can increase under certain circumstances as well.
So what I think is where I think the best place to go is if we had no research, I would specifically be looking at anecdotal stuff because it’s like, well, that’s not ideal, but I’d go there if we didn’t have research, but we do have some relevant research. So the autoimmune protocol diet, which we have spoken about previously on the podcast, that cuts out nightshades as part of the overall approach. So while I’m not necessarily looking at research on nightshade specifically, I’m looking at something that cuts out nightshade. So theoretically, if this was, let’s say magical and solved everything, it should show up in this research. And the short version is that on average, the limited research that we have on the autoimmune protocol diet has found modest improvements in autoimmune conditions on average.
But as I spoke about in that other podcast, we also see improvements when people are improving their nutritional quality in general of their diet. If they cover a bunch of different micronutrient inadequate intakes or deficiencies, often symptoms improve a little bit as well. And in those studies in particular, I would say that things were swayed a little bit because there’s a bit of added buy-in because they were reading books on the subject like they were reading books, they’re saying, here’s how good the autoimmune protocol diet is. And then there was self-reported symptoms. So like if you think you’re doing something that’s going to help you, that could be a little factor there.
But although I’m mentioning research that’s not specific to the United States, it gives a bit of an insight that it isn’t necessarily simple solution for a larger centre of people with autoimmune conditions. We could read into it and be like, why did the autoimmune protocol find improvements at all? Was it as simple as I might have suggested with it being like they are increasing the overall nutritional quality of their diet? Because most people have a relatively poor diet at the baseline. The autoimmune protocol diet is basically a stricter paleo style diet, which although that can have flaws, it is quite a nutrient rich diet.
Or did these people have modest improvements because they were cutting out certain things, for example, nightshades? It’s a bit up in the air in terms of what is the main factor there. But I think at minimum one takeaway would be that it’s clearly not an answer for everybody if there is some potential benefit there.
Leah:
Yeah, so should or could there be a case made for some people eliminating them? So everything we have spoken about has been more so at a population level, whilst also acknowledging that the levels of a lot of these compounds in these foods are quite low in like regular consumption. But there is still a possibility that looking at an individual level that you could personally find you have issues with nightshades or things in that family. So it’s not an approach we typically recommend, but we could probably test this fairly easy in that if you think nightshades are an issue for you and contributing to certain symptoms, you could periodically just take out all nightshades from your diet. If things improve, all right, maybe you just leave them out.
So they’re not like a make or break for a well-balanced diet. Like you can remove them and still have a healthy, well-balanced diet. So if you’re finding that there is a crossover for you personally with certain symptoms and avoiding them is best for you. That’s totally something that you could do. But we would say it would probably be best to like have a little bit of trial and error over time where maybe you reintroduce them at various intervals or play around with introducing certain ones in certain quantities to test things like.
Well, are you only reacting to certain nightshade vegetables? Is it only in certain quantities? And like, is there a certain level of tolerance there? So I think there’s definitely like, it’s worth playing around with and not seeing it as super black and white, but it is something that you could trial if this is something that’s on your mind and you think is contributing to certain symptoms. And anecdotally, some people have found that certain things do seem to be more of a trigger than others. So you might find that, oh, maybe eggplant, tomato, huge problem, but potatoes, not so much. So definitely worth playing around with.
Aidan:
Yeah, just looking on forums, there was so many people who were like, this one’s an issue for me, but this one’s not.
Leah:
Yeah, which for me is like, that pointing to something else being at play here? But in saying that it’s like a somewhat easy test.
Aidan:
That’s a valid point as well. The next bit I go with, anytime I say, it’s okay to like take something out and just test for yourself. The next step that I always have is what are we taking out and is there anything we can or should replace? For example, if somebody completely cut out orange vegetables, I would instantly be like, maybe we need to look at vitamin A and making sure that you’re getting enough of that from another source, for example, liver or something like that. Many of these specific nightshade vegetables, like you can get a load of these or you can get all of these nutrients from other sources. So like that’s totally fine. But I’d always look at that first. Like I wouldn’t just take something out without looking at how to replace it.
But general summary, at a population level, nightshade vegetables, totally fine. I would even go a bit further and say they’re typically beneficial. Add to most people’s diets. But at an individual level, I would be open minded to the fact that it could still be a possibility that it might be a factor for you. And it could be worth doing some trial and error even through the lens of maybe it’s the nightshades and these components in there or maybe it’s something else that is also in some of these vegetables for example.
Leah:
This has been episode 188 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or review, it’s always greatly appreciated for you to do so, but otherwise, thanks for tuning in.