Hello and welcome to the Ideal Nutrition Podcast. I’m Leah Higl, and I’m here with my co-host, Aidan Muir, and today we’ll be talking about magnesium and its impacts on sleep.
So the mechanism for how magnesium can help with sleep is super clear, super easy to understand. Basically, it can increase this thing called GABA that can help us enter a more relaxed state, which theoretically makes it easier to fall asleep. The research and outcomes is a lot more mixed than you would expect based on that very, very clear mechanism, but it’s an easy to understand mechanism, and we will go through the research situations where it can help, situations where it might not help, and situations where it’s a little bit less clear as well.
We’re going to start by talking about the anecdotal evidence that we have around magnesium and sleep, and realistically, we see heaps of examples of people who have tried magnesium for sleep and have reported benefits. I know I’ve had countless clients, you’ve probably had countless clients who have said, “I have magnesium before I go to sleep, and I feel like it has improved quality, length of sleep etc.”. So a lot of our clients have tried this. A lot of clients that have also measured their sleep quality using devices and watches and things like that and have noticed benefits from doing so.
But of course there are both pros and cons of anecdotal evidence. One of the major cons is the lack of a placebo control. So the fact that there are other variables that can change in the real world that could be impacting on that outcome rather than it just being from the magnesium. But the major pro is that we actually don’t have a heap of research on this topic. So the anecdotal evidence that we have is slightly more relevant in this case than in a topic that we have heaps of actual RCTs, like randomised control trials and different actual research for.
So a good starting point would be what I’d call a proof of concept type of idea, which is what happens if you have too little magnesium, because theoretically, that should be the easiest place to start, like having too little magnesium. If there’s a link between the two that should cause issues with sleep. So while there is not a lot of research on this, it is clear that magnesium deficiencies and very low intakes of magnesium in general are linked with worse sleep. This could be addressed through either food or supplements to address that, but something that’s a bit of a starting point is that having a suboptimal intake of magnesium is super common.
So the recommended daily intake is 400 to 420 milligrams for men and 310 to 320 milligrams for women. I, in a previous job, used to do nutrient analysis of all my clients’ food diaries. There’s a lot of reasons why we did that in that job, and we know that food diaries aren’t a perfect representation of what people do. But on average, I’d see people getting 50 to 60% of that kind of recommended daily intake. So we know that a lot of people are falling short of that target. Magnesium amongst a few other ones is one of the most common ones that people would fall short on. That being said, having a deficiency as defined by a blood test is quite rare. When you look at blood test and it says magnesium on it, how often have you seen a deficiency?
Rarely ever. I think maybe a couple of times.
Yeah, I think a couple of times for me too. Usually on a blood test that’s a sign that something else is going wrong, say kidney function or something else.
So deficiency as based on a blood test is very, very rare. Other definitions of deficiency based around intracellular magnesium levels are reportedly quite common. But we can’t test this easily, and it’s hard to say how much this matters based on the fact that it’s not tested very easily. It’s not common and is apparently pretty expensive to get that as well. And there’s no real clear gold standards or anything like that. So instead of me necessarily looking at that deficiency thing because it’s kind of hard to measure, I would look at it, probably not the perfect way. But I’d look at it being like, what is a suboptimal intake of magnesium in comparison to say the recommended daily intake? Keeping in mind that the recommended daily intake is not representative of your needs. For example, an athlete with really high training loads whose sweating heaps, probably requires a little bit more magnesium than that. I just like to put a number like the recommended daily intake out there so we have context to work from.
Especially when looking at food sources and stuff, it’s good to have context.
So next topic we’re going to talk about is magnesium and insomnia. So one of the most cited studies on this particular topic involved 46 older adults with insomnia. They compared 500 milligram magnesium supplementation to a placebo. Overall, the magnesium group got significantly better quality and quantity of sleep. When interpreting this though, it is worth highlighting that older people are more likely to have lower levels of magnesium due to both a lower dietary intake of magnesium, but also lower levels of absorption.
So therefore they are potentially more likely to benefit from supplementation than someone else. We also expect to see larger improvements in sleep from those who struggle with insomnia versus people that already get somewhat decent sleep. So I think just looking in at sleep research, there’s looking at sleep and then there’s looking at people with insomnia, and there’s not always obviously a direct overlap. We would expect more of a result from people in those insomnia-based studies. So whether or not this kind of translates over to just general sleep, less clear. A 2021 systematic review of magnesium and insomnia found 3 randomised control trials and overall people got to sleep on average 17 minutes quicker, and had a total increase in sleep time of 16 minutes. So generally that looks really promising, but obviously we do have the drawbacks of insomnia versus just general sleep.
Yeah, yeah, I like that. I think that idea, once again, proof of concept, older people with insomnia, this is the group we would expect the most benefits in, and we did see benefits in that. And then that systematic review, not necessarily just on older people, that increases, once again, that looks promising. Downside as mentioned is there’s only three randomised control trials, coming back to that concept of anecdotal evidence being like if everything we see anecdotally seems positive and there’s no randomised control trials, I pay attention to it.
If everything seems relatively positive and we had 20, just go extreme, 20 randomised control trials showing no benefit, I’m like, okay, I’ll ignore the anecdotal evidence.
This kind of space with the insomnia, I’m like, this looks pretty promising. The next topic though, and I think this is what a lot of people are interested in, is just magnesium in general sleep. There’s a lot of people who, I don’t want to say they’re necessarily just trying to optimise everything but are trying to improve sleep. If we have a simple way of improving sleep, it makes sense to explore it because there’s so many benefits of sleep. So higher dietary intakes of magnesium have been linked with better sleep. That is something that has been pretty well studied and there’s a pretty clear cut link. But randomised control trials that are more tightly controlled, have more mixed findings.
While most people have what is considered to be an average or a suboptimal intake of magnesium, randomised controlled trials haven’t really found evidence that supplementing beyond these average intakes has found clear benefits. Keeping in mind that there’s actually not that many randomised controlled trials looking at that so I’m not personally reading too much into that. But it’s worth knowing that it’s like, I don’t know, I spend a bit of time on TikTok. I see people talking about magnesium and sleep and how much of a game changer it is. And a lot of people with comments will be like, “This has changed my life. I get good sleep,” etc. When people say they’re struggling with sleep, I see a lot of people recommending magnesium and it’s interesting that’s this is a relatively common recommendation, but we don’t actually have randomised control trials supporting it for general sleep. So I’m a bit hesitant with the recommendation and everything like that.
But one point that I will add onto that is it’s relatively cheap and safe, so it is an easy option to try. Plus, if you personally have a lower intake of magnesium than the average, you are more likely to benefit from that. And without getting too into the dietary sources of magnesium, a large percentage of what we would call “healthy foods” will contain a certain amount of magnesium, which therefore means, what I’m kind of saying is if you have a lower quality diet in general, you probably have a lower intake of magnesium in general and would benefit more from supplementation than somebody who already had a good amount of magnesium.
And when it comes to magnesium and general sleep, I kind of see it from two perspectives. I see it as a potentially easy win and easy thing to try, but I also kind of see it as potentially also missing the forest for the trees in that there might be things that are more beneficial. It’s like in nutrition, I mean they say about surgeons and stuff, if you have a hammer, everything looks like a nail.
So I like to think of, well, there’s probably a lot of things outside of magnesium and supplements, nutrition that obviously can benefit sleep potentially way more, but also maybe it’s an easy win. So I like to see it from both directions. But let’s talk a little bit about food versus supplements. So since there clearly has been a link between better dietary intake of magnesium and sleep, it does make sense to focus on getting sufficient amounts through food. And like you said, an overall higher quality diet is … It’s usually going to be higher in magnesium than a lower quality diet. So getting in all those kind of whole foods.
But if you’re not getting enough through food, it does make sense to supplement. One argument that could also be relevant is that the acute effect of magnesium might be playing a part. Having that kind of high dose of magnesium before sleep might be having a specific outcome that having just sufficient amounts of magnesium day to day is not particularly having. So supplement dosages are often around that kind of 300 milligram mark, which can be a lot to get through food, particularly if you’re trying to do it in one sitting. That’s pretty difficult. But timing that around one hour before bed could be unique to supplementation and its benefits.
On other topics, restless leg syndrome. So a lot of people anecdotally report magnesium helping with restless leg syndrome. Heck, when I made a post on magnesium and sleep on Instagram because I try to batch some topics. I try and do it on podcasts and Instagram, relatively similar times, save myself a little bit of work. But I posted this on Instagram recently, and even then somebody was like, “Oh yeah, this helped my restless leg syndrome.” It is a very common anecdotal thing. But a 2019 systematic review on the topic had mixed findings and it was not overly promising. Once again, I think it is worth trialling. There is enough anecdotal people reporting that this has helped something. It’s worth trialling, but it’s clearly not as effective as consistently as some people make it seem like. If you have tried this and it has helped, I’d pay attention to that. But I also wouldn’t have it be a frontline recommendation and be like everyone with restless leg syndrome needs to try this because it works consistently.
Talking about side effects a little bit. So side effects of high dose magnesium supplements, they can potentially lead to things like diarrhoea, nausea, and vomiting. So that’s just something to be aware of. For context, other supplements like magnesium citrate are commonly used as a laxative, and so if you are taking really high dose magnesium, it could have that potential side effect.
And that’s also in that dosage of 300 milligrams, magnesium citrate is sometimes used as a laxative.
So it’s food for thought that, yeah, it could be an issue if you are trying to get to sleep. But looking at dosages in general, so something that I found very interesting personally when I was going through research is that most of the research didn’t even say what type of supplement they specifically used. So if we’ve got three randomised control trials on insomnia, a couple of trials here and there just on general sleep, and they haven’t even said what type of magnesium they’ve used and were kind of like, “Oh, the research is pretty mixed on this for general sleep.” It’s pretty hard to make strong recommendations. The one I’m seeing the most frequently is magnesium glycinate or glycinate, and it’s probably the most common option recommended for this purpose. A lot of reasons people recommend that one specifically is because it isn’t magnesium citrate, it’s less likely to cause diarrhoea or anything like that. Although I also do see magnesium citrate being a common recommendation.
So I have a few thoughts. One is that we don’t have a bunch of research being like, in a perfect world, what we would have is heaps of randomised control trials comparing to placebo, proving that this has consistent benefits etc. And then comparing magnesium glycinate and magnesium citrate and comparing them all to each other and seeing which one performs the best. We don’t really have that, but because I’m pretty open-minded about the various forums being like, “Oh, I recommend magnesium glycinate for this or glycinate.” But if somebody else had a different recommendation, I can see why as well. And the standard dosage is around that 300 milligram mark. Once again, keeping in mind that researchers said different amounts. Like that insomnia one we talked about before used 500 milligrams. And the timing is one hour before bed because on the one hand we’ve kind of spoken about how greater intakes of dietary magnesium have been shown to help with sleep.
But let’s say there is a bit of an acute effect of magnesium on GABA increasing and the timing of that in relation to bed being useful. If the recommended daily intake is somewhere between 300 and 420 milligrams and the average person is getting say, 50 to 60% of that number, keeping in mind that’s a loose average. If you went and found legitimate numbers, maybe it’s a little bit higher, maybe it’s a little bit lower. But if the average person is falling short of that number and there is an acute benefit of having it around an hour before bed, you could see an argument for supplementation over the food because most people aren’t getting enough anyway.
This has been episode 106 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or review, it would be greatly appreciated for you to do so. Otherwise, thanks for tuning in.