Magnesium supplement FAQs, answered by Prof. Dr. Jürgen Vormann

Could you start by introducing yourself and your work?

Yes, my name is Jürgen Vormann. I'm a nutritionist and professor of biochemistry, and I'm head of the Institute for Prevention and Nutrition in Ismaning, that's close to Munich in Germany. And I'm involved in research on minerals and substances that are active in our food and can be used also for medical purposes, since many, many years. And one of my specialties is the biochemistry and the physiological functions of magnesium.

And how did you become interested in magnesium specifically?

Well, it was long ago, when I started my PhD. I already worked on magnesium, and during that time magnesium was even called "the forgotten ion", because there was not much research on magnesium. It was not known how magnesium status is regulated, and how magnesium is transported through cell membranes, and so on. But it turned out that now, really, magnesium is extremely important, and in our societies we have really a significant shortage in the supply of magnesium. So magnesium deficiency is, I would say, with regard to minerals, by far the most widespread problem that we have.

There are studies from the States, also from different countries in Europe, that say that up to, minimum, one third of the adult population is deficient in magnesium. So really we have a problem there, and we should address that, as magnesium is extremely important. This came also out within the last decades: that really we now know there are more than 600 enzymes that are magnesium dependent. Magnesium is our physiological calcium antagonist, with really important pharmacological properties. I think there is no cell within us that is not extremely dependent on sufficient magnesium.

And as you mentioned, a lot of people are magnesium deficient. What would be some of the health problems that come from that?

Well, as magnesium is needed in every cell, the main problems are not so singular. Of course, if you have a calf cramp, this can be caused by magnesium. However, calf cramps are not very nice to have, but it's not life-threatening. However, what is much more important is that magnesium deficiency is very often connected to heart arrhythmias. And by that, magnesium is really giving us some protection against, for example, sudden cardiac death. There are large studies showing there is a close connection between magnesium status and sudden cardiac death. So simply with that, you can see that really magnesium is a life-saving mineral, and in addition to that has numerous other very important functions. For example, the insulin binding to the insulin receptor is a magnesium-dependent process. Meaning, if there is a magnesium deficit, then insulin is not working properly. So in all patients with diabetes type 2, high magnesium supply is very advisable.

It's involved in hundreds of chemical processes in the body and key functions of cells. So what do you think are some of the biggest misconceptions with magnesium supplements?

With magnesium supplements. First, for many it really makes sense to take a magnesium supplement. Then, first, you need to take a supplement that has sufficient amounts of magnesium. So our usual magnesium need is in the area of 300 to 400 milligrams on a daily basis. Usually we should get this from diet. Unfortunately, diet is very often not so high in magnesium, and we eat fast food, we eat foods that are not very rich in magnesium. So generally the risk to slide into a deficit is quite high. If this happens, then at first our body helps itself simply by releasing magnesium from the bones. The bone is our natural magnesium store. Half of our body magnesium resides in the bones. In the beginning, we don't realise that, and don't feel that there might be a magnesium deficit, because we take it from the bones. So, to supplement magnesium, I would really say simply double the usual intake, meaning you should take a supplement with a minimum of 300 to 400 milligrams magnesium on a daily basis.

Then the second point is, and very often people don't realise: when there is written on the supplement, let's say, 500 milligrams magnesium whatever, oxide or citrate, then they don't realise that this is not the amount of magnesium that is needed, but it's the amount of the total magnesium salt. As we cannot take magnesium as a single substance. This is not possible. We always take magnesium in combination with salts: with magnesium oxide, carbonate, citrate, whatever. So many different substances on the market. So at first, it must be clear that you really have a sufficient amount of the really elemental magnesium, what you need. So this is sometimes confusing if you look at different supplements.

The second is, of course, the magnesium must be bioavailable. Usually, the magnesium that we ingest from our diet, the bioavailability is not very high. We only absorb roughly one third of the magnesium from our food. And the same, more or less, is true for the supplements. So meaning, when you ingest 300 milligrams, you will only really absorb about 100 milligrams of that.

And there are certain principles for the absorption of magnesium in our intestines. At first, only free magnesium ions are absorbed. That means there is no complex whatsoever that supports some kind of magnesium uptake. Magnesium is only absorbed as free ions. We now know all the transport mechanisms, all the transporters, the different transporters in the cells and cell membranes, and we have transcellular absorption processes. But all these transport processes only take free magnesium ions. So what we need, when we take the supplement: we must release the free magnesium from this supplement.

For that, very often we need gastric acid. The gastric acid releases the magnesium from the food that we are eating. We have to release the magnesium, and we need the gastric acid. Think of all the millions of people taking proton pump inhibitors to reduce the production of gastric acid. These really have a problem then with absorption of magnesium, simply because the magnesium is not released from where it was bound, or is bound.

It's important that you take magnesium in a form that can easily release the magnesium from the salt where it is bound. And the physiological binding substances of magnesium in our food, these are mainly the organic anions like citrates, malates, gluconates. When we eat an apple, we ingest the magnesium not as free magnesium, but bound to these citrates, malates, gluconates, these organic anions. That's the physiological substance I would prefer for a supplement. So then, when we take that, in our intestines this salt dissociates. And then, if we stay with one substance like, for example, the magnesium citrate, then we have the magnesium ions and we have the citrate. And then the magnesium ions are absorbed, and by a different mechanism also the citrates are absorbed. So the most important point is really: you have to have a system where free magnesium ions are available. And then these magnesium ions are absorbed through different pathways, transcellular or paracellular pathways.

But what is common to all these pathways: only free magnesium is absorbed. There is no complex. You cannot bind magnesium to whatever substance and absorb it. It simply doesn't work, because the transporters, they have little holes. These holes are just as thick as a free magnesium ion can pass through it, but not a magnesium complex, let's say, bound to some amino acids or to other substances. It simply doesn't work. So all claims that say that magnesium bound to some substance whatsoever would be absorbed better, this is simply not true. It doesn't work. That's just, well, to be honest, this is only marketing, nothing else.

If you ingest magnesium, within your intestines the compound that you take must be separated into magnesium ions and the other, let's say, the citrates or the lysinates or whatever is on the market. But the amino acid does not help with regard to the absorption of magnesium. So the point is: first, take enough magnesium. Second, have it in a form that it can be dissolved in the intestines very easily. And then it must dissociate, and in that, acidity helps. So if you have sufficient production of gastric acid, this helps to release magnesium from the compound, whatsoever. And then magnesium is absorbed.

And when magnesium is absorbed and comes into the blood, then the magnesium has totally forgotten to what it was bound before. So all claims that say a certain magnesium salt would bring magnesium into a specific organ, a specific tissue, this is, simply, there's no truth in it. Because when magnesium is in the blood, there's no connection to the substance that you ingested, that you took as a supplement.

So have magnesium in sufficient amounts, have magnesium in a form where magnesium can be released. For example, if you take a drink with magnesium, you have already the magnesium dissolved. And then, if you have the gastric acid, the chance that you have free magnesium ions is a little higher. So then maybe a supplement that you can drink is a little better than a supplement that you have as a tablet or capsule or whatever. But this is, well, the difference is not extremely high, but there is some difference.

So the first thing is to take a magnesium with a high enough amount. And the second is in a form that your body can dissolve. You mentioned citrate and malate as forms that are relatively easy to dissolve in the stomach. What about magnesium oxide? Because that has a super high elemental amount of magnesium, but we've seen research that it's actually quite poorly absorbed, and it can cause stuff like diarrhoea, right?

Well, with magnesium oxide, that's the point. Magnesium oxide needs an acidic pH to dissolve. So if you take magnesium oxide without having proper production of gastric acid, then the magnesium oxide will not dissociate, and you will not have enough free magnesium ions. So if you take magnesium oxide, I would say take it 10 to 15 minutes before you eat something. Because then already the production of gastric acid, because you're looking forward to some meal, already the gastric acid is produced, and then the magnesium oxide falls into this gastric acid, and then that's fine. Then you have a good bioavailability. But if you take the magnesium oxide after a meal, then the chance that this magnesium is very well dissolved and dissociated is lower.

So generally, I would not say that magnesium oxide does not work. There are really hundreds of studies where magnesium oxide was given, because it is one of the cheapest supplements. The positive thing is the relative amount of magnesium in magnesium oxide is high. You have up to 60% of the total volume that you ingest is magnesium. If you take an organic magnesium salt, then the relative amount of magnesium is much lower. For example, if you take magnesium citrate, then you have roughly about, depends on what kind of citrate you take, something about 15 to 16% of the total salt that you ingest is magnesium. Meaning, when you want to take 300 milligrams magnesium, you need to take two to three grams, or 2.5 grams, of this salt. So you can't take this within a single capsule or something. Then it's better to take a drink, or dissolve that, and then you have a good bioavailability. Yes, generally the bioavailability of organic magnesium salts is higher than of, specifically, magnesium oxide. At first it's important to take magnesium, but then I would prefer an organic magnesium salt.

There's pros and cons.

What would you say your favourite is?

Well, we have done several studies specifically with magnesium citrate, and the citrate really has a good bioavailability. And this is the physiological magnesium substance. When you eat the proper diet with sufficient amounts of magnesium, then most of the magnesium comes with citrates. So why not take that, what is easy to get? And there's a second point with magnesium citrate. Of course, you not only have the magnesium, then you have also the anion, the citric acid anion. And this, on our metabolism, has an alkalising effect. And so you have two very important aspects when you take magnesium citrate. You have on the one side the magnesium, and on the other side you have the citrate that gives you an alkalising effect. And this alkalising effect is very important, because most of the people now have a so-called chronic latent metabolic acidosis. So we have too much acidity, because our diet brings us an acid burden, and we have to compensate that. And if we don't do that on the long term, this poses problems.

So citrate helps counterbalance that.

Yes, the citrate is able to neutralise. The citrate can bind acid, can bind protons, and then this is easily metabolised. So then we get rid of a surplus of acidity. And this is for sure also beneficial, as well as the high intake of magnesium. So you have two aspects with one compound.

Citrate seems like the best one then. I had no idea about all this. That's awesome.

I would say citrates are the best, or also malates or gluconates are best. Most supplements are now, at least in Germany where I'm from, we have the citrates, and they are quite widespread.

However, there's one negative aspect with too much magnesium. This might induce diarrhoea. That's the point. If you assume that only one third of the magnesium is absorbed, then the rest of the magnesium stays in the intestines, and the magnesium then binds water, and this could induce, if you take too much, diarrhoea. I know patients that have certain diseases, genetic diseases connected to the regulation of magnesium, and they have less activity of magnesium absorption capacity. They need to take very, very high amounts of magnesium, up to 2,000 milligrams of magnesium on a daily basis. And this, of course, then induces, minimum, loose stool.

So for some, taking magnesium, this is, well, I would say, a welcome side effect. As constipation, if you have a problem with constipation, I would always say at first you should try magnesium to get rid of that. We did studies with pregnant women, and also in pregnancy constipation is very, very common. And then simply the women should take magnesium, having less problems with constipation, and having the beneficial effect of sufficient amounts of magnesium. Because then this magnesium, in the pregnant women, can reduce the risk for pregnancy-induced hypertension, can reduce the risk for pre-eclampsia. I don't know how it is in England. In Germany, I would say 90% of pregnant women take magnesium. And this really makes sense.

Interesting. And so is perhaps that why oxide can have the diarrhoea effect, because it's so high in magnesium?

It's high in magnesium, and then, yes, then in the colon our microbiome leads to dissolution of the magnesium oxide, and then you have magnesium there, and then it can lead to loose stool or diarrhoea.

However, we also now know that it's very important that it's not only the magnesium that is absorbed that is important, but also the magnesium that comes into the colon, because it feeds our microbiome. And the microbiome is now, fantastic or fascinating new developments there, with how important that is. And also the microbiome needs a lot of magnesium. And maybe this is another aspect that is, well, I would say, will turn out maybe in the next years: that really, to feed the right microbiome with the right magnesium is also a very important aspect of a sufficient magnesium supply. So we have different areas where magnesium is working.

Coming back to the effect of magnesium, that is, what happens if it is properly absorbed? We need the magnesium also for our brain. And there are new studies that really show that there's a close connection between sufficient amounts of magnesium and brain function. And so, with this large problem with dementia, there also a high magnesium intake might help. And there are large studies going on. It seems to have a dramatic effect on the brain. For example, also with depression, there are large epidemiological studies that show: the higher the magnesium intake, the lower the risk to develop depression. So brain function is, I would say, one of the hottest topics with magnesium. And for that, you simply need to have magnesium intake. And if you have an increase in blood magnesium, of course then magnesium also goes into the brain, and then we have the beneficial effects.

That's interesting about the brain, because we have on the market magnesium threonate, right? Which claims to cross the blood-brain barrier. But from what you've said, you don't think that's true, right?

No, I don't think that. Well, it's true, if you take magnesium threonate, then you take magnesium. And then magnesium is absorbed, and of course magnesium then also goes into the brain. And we did studies with certain patients, with certain genetic diseases, that had very low brain magnesium content. This is not easy to measure, to determine. But we could do this at the University in Vienna with tomography. And we could show that simply by taking physiological magnesium, with magnesium citrate, you can normalise the brain magnesium content.

And I would say, of course, there are no studies that compared directly, in patients, one magnesium compound with the other. But we all know magnesium goes into the brain. Of course, we could not live otherwise. Our brain cells, they all need magnesium, and they take the magnesium that we have ingested with our food, or with any supplement, with a supplement whatsoever. It doesn't matter. The main point is you have to increase the blood magnesium, and then you bring magnesium also into the brain. So if you take magnesium, what they claim, magnesium threonate, that this magnesium threonate... well, there is no complex of magnesium and threonate in the blood. So how should the magnesium know, in the blood-brain barrier, that it was ingested as magnesium threonate? It doesn't make sense, somehow. And all the studies they showed is that really, of course, magnesium works. But of course then, if you have a good availability of the magnesium, it goes into the brain and has beneficial effects. Of course. Yes.

Wow. People are going to find that super interesting, because obviously magnesium threonate is very expensive.

That's another point, yes. So people then reduce maybe the intake, because it is so expensive. And this doesn't make sense in my eyes. It's more proper then to take a reasonable magnesium supplement. There are many, many supplements on the market that are quite reasonable. So take enough magnesium, then.

There are many studies, for example, in migraine patients. And of course, migraine is a problem of the brain. There are placebo-controlled, double-blinded studies that show that, for example, with magnesium citrate you can reduce migraine problems. Roughly 50% of the migraine patients will see a significant benefit when they take high-dose magnesium supplements, specifically magnesium citrate. The studies are there, and I simply would suggest to use that.

We touched earlier on how you might see 3,000 milligrams of magnesium citrate or magnesium malate on the label, but you're only getting, say, 15 or 16% of that in elemental magnesium. Why is that? Is it a chemistry fact that you can only get so much magnesium in magnesium citrate, malate, glycinate?

Well, that's simple chemistry, because the citrate anion is larger than the magnesium. So if you take the whole compound, magnesium citrate, it's a little more complex, because you have complexes that contain two citrates connected with three magnesium. It doesn't matter. Roughly about only 15% of the whole is magnesium. You can't change it. You cannot fill in more magnesium into the citrate. You can't do this. The chemistry is... you can't betray the chemistry.

Because in the industry we know that a lot of brands will put a higher number. So they might say, you know, magnesium citrate providing 400 milligrams of elemental magnesium. But you send it to a lab and test it, and it does have that much elemental magnesium. But we know from industry insiders that they're adding oxide to the tablet, and then not putting it on the label.

This is, well, I would say, this is of course not correct. If you claim it's magnesium citrate, it should be only magnesium... the magnesium should only come from the citrate, and not from the oxide. Then you should say, okay, of course, there are supplements that have, let's say, I don't know, 50% is magnesium oxide and 50% is magnesium citrate. But that's okay, why not? But then it should be claimed. You should not say, well, I have high amounts of magnesium with relatively low amounts of citrate. This can't work. You can't fool the chemistry. This is not possible.

Yeah, it's happening a lot, and we're trying to spread awareness about it.

We mentioned earlier about diet, and how if you're going to take a magnesium supplement before, maybe like smelling food, that's going to help the absorption. What about diet in general? Because people might also be getting some magnesium from food, but then still taking the supplement. Does that make a difference, really, whether you're getting it from food or from a supplement?

Well, generally it's not a big difference. Because, of course, we always... the best is to get all what you need from food. But we know that people don't eat what is usually suggested. Especially these ultra-processed foods that have low amounts of magnesium. Also, when you prepare your food, you can lose magnesium. For example, if you cook a potato, you extract half of the magnesium into the cooking water, and most people throw that away. And the same with vegetables and so on. So with all cooking processes, with many cooking processes, we reduce the magnesium content. And so it's not only important to read what is the amount of magnesium that is, let's say, in a potato. You must really see what exactly do I eat. So if you use a lot of water boiling the potato, then, well, simply you lose a lot of magnesium.

And also, if you look at all these industrial foods, the amount of magnesium is really low. That's the problem. That's why we need supplements. We eat usually a diet that is low in magnesium, and then we have the risk of magnesium deficits. And so I would say, well, being a nutritionist, I would say first try to eat the proper diet. But if this does not work, then take the second-best choice: take a reasonable supplement, and make sure that this supplement is reasonable, that it's the right dosage, and the ability to absorb it should be high.

And what about measuring for magnesium levels? Is just a blood magnesium test a good enough indication?

Yes, practically it's only the blood magnesium. But there's also one new development in that. Usually the serum or plasma magnesium is determined. Then, depending on the lab where the measurements are done, you have certain reference values. If you look into the medical literature, you see reference values from 0.7 to 1 millimole per litre serum. However, now we know that already within the reference ranges, when you are within the reference ranges, if you are below 0.85 millimoles per litre serum, there is a magnesium shortage. So there are new publications on that, and worldwide it is now accepted that really the plasma magnesium concentration should be above 0.85 millimoles per litre serum. And if you have this value, well, then you can be relatively sure that you are fine with magnesium. All studies that have been done show: if the values are below 0.85, then, if you make balance studies, there is an uptake of magnesium into the body. So it shows there was a deficit before. But this is quite complicated. So now, generally, the value should be above 0.85 millimoles per litre.

That's what people should aim for. Cool. I think that's everything. That's going to be a super awesome podcast, thank you so much. People are going to find that super interesting, especially about the threonate, because I know so many people are like, oh my god, this crosses the blood-brain barrier, this is the best thing ever.

Yeah. So take enough magnesium, then also your brain will be supplied, and you will have all the beneficial effects.