Magnesium is a key mineral that is essential for muscle contractions and nerve transmission while also keeping your heart beating steadily and your immune system strong. Of the many health conditions linked to magnesium, it is poor sleep quality that often comes up as a reason to take magnesium supplements. In this podcast, I’ll look at the latest evidence for magnesium and sleep. And then I’ll profile the main food sources of magnesium and critique the merits of the many different supplemental forms of magnesium.
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Magnesium is a key mineral that is essential for muscle contractions and nerve transmission while also keeping your heart beating steadily and your immune system strong. Of the many health conditions linked to magnesium, it is poor sleep quality that often comes up as a reason to take magnesium supplements. In this podcast, I’ll look at the latest evidence for magnesium and sleep. And then I’ll profile the main food sources of magnesium and critique the merits of the many different supplemental forms of magnesium.
Links referred to in the podcast
Episode transcript
To access the full episode transcript, go to the following link and select the individual podcast episode and then click on the ‘Transcript’ tab https://thinkingnutrition.buzzsprout.com
Connect with me
Instagram: doctimcrowe
Facebook: Thinking Nutrition
Magnesium is a key mineral that is essential for muscle contractions and nerve transmission while also keeping your heart beating steadily and your immune system strong. Of the many health conditions linked to magnesium, it is poor sleep quality that often comes up as a reason to take magnesium supplements. In this podcast, I’ll look at the latest evidence for magnesium and sleep. And then I’ll profile the main food sources of magnesium and critique the merits of the many different supplemental forms of magnesium.
Magnesium is an essential dietary mineral. You have about 30 grams of magnesium in your body with half of this in the bones. Much of the rest of it is in the muscles and soft tissues, with only 1 per cent in the extracellular fluid where it serves as an electrolyte. As an electrolyte, it helps to maintain fluid balance.
Magnesium is also a cofactor for hundreds of enzymes. Magnesium is involved in many metabolic pathways, including energy production, nucleic acid and protein synthesis, and cell signalling. And together with calcium, magnesium is involved in muscle contraction and blood clotting. That’s a lot of work for one mineral.
There are many health conditions linked to magnesium, or at least a magnesium deficiency. These include heart disease and high blood pressure, diabetes and muscle cramping. I’ve already done a general podcast on magnesium and health way back in episode 22 so grab that episode to get up to speed. But for this podcast, I want to focus on one health area and that’s poor sleep quality.
Sleep quality
And here is the rationale at least for why magnesium is a commonly recommended supplement to improve sleep. To fall asleep and stay asleep, we need to be relaxed both physically and mentally. That’s obvious. Magnesium may help with this process by activating the parasympathetic nervous system which is the system responsible for getting you calm and relaxed. It does this through various neural and hormonal systems including neurotransmitters and regulation of the hormone melatonin, which guides the sleep-wake cycle in your body.
That all sounds good, but can a magnesium supplement actually get you to sleep and keep you asleep outside of any placebo effect it can have? Despite a lot of research looking at this question and which can be very mixed in their findings, there haven’t been a lot of critical reviews bringing together all the research in the one place. So that was the purpose of a recent systematic review published this year. And I’ll link to the study in the show notes. https://pubmed.ncbi.nlm.nih.gov/35184264
This review analysed data from 9 research studies involving over 7,000 participants to determine whether a person’s magnesium status is associated with sleep quality and importantly if supplementation had a positive benefit in controlled trials that used a placebo.
And here were the findings. For observational studies looking at magnesium status and sleep quality, there did appear to be a positive link with an association between higher magnesium intake (from diet and supplements) or magnesium status and better sleep quality. That’s all nice, but these are observational studies and there could be other unknown factors explaining the link that were not related to magnesium.
So, what about the gold standard randomised-controlled trials – what do they have to say? Well, agreeing with my prior view when I’ve looked at the studies before, the results are….mixed and inconsistent. One study with 46 older participants who took 500 milligrams of magnesium or a placebo for 8 weeks found that magnesium supplementation increased sleep time and sleep efficiency. But the other 4 controlled trials examined in the review did not produce statistically significant improvements in sleep outcomes.
None of this means there wasn’t any benefit, only that it was pretty hard to pick it up and there is a question if any benefits were of clinical significance. But, but, but as always, these studies represent the averages of everyone in the trials and as human beings, our responses will be variable.
Taking a more global view, it is certainly not some endorsement that everyone should take magnesium and it will instantly improve their sleep. For many, it could just be a placebo effect, but hey, if I’m lying awake struggling with insomnia then I’d happily take a placebo pill if I believed it would get me to sleep better, because if you believe in it, well, it may just work.
But back to the science. What it is saying to me is that the benefit of magnesium on sleep, if it is really there, is likely quite small. But the research field is pretty modest so one shouldn’t dismiss it or endorse it one way or another.
Magnesium deficiency and foods
Okay, so, can a magnesium deficiency be a likely thing to explain poor sleep in many people? And if so, what are the best ways to get plenty of magnesium in your diet? While there are many food sources of magnesium, there is no one food source that stands out so even the best sources tend to only meet about one-fifth of needs. Since magnesium is part of chlorophyll, the green pigment in plants, green leafy vegetables are good sources with spinach being one of the best sources. Wholegrains and nuts such as almonds also have good amounts of magnesium in them. Meats and milk have an intermediate content of magnesium, while highly refined foods generally have the lowest.
Even with an adequate diet, some people are at increased risk of magnesium deficiency, including people with digestive disorders, such as celiac disease and chronic diarrhoea.
In the short term, getting too little magnesium does not produce obvious symptoms. Low magnesium intake for a long time, however, can lead to magnesium deficiency. Symptoms of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness. Extreme magnesium deficiency can cause numbness, tingling, muscle cramps, seizures, and an abnormal heart rhythm.
Supplements
So what about supplements then? There are many different formulations to choose from if you’re thinking of trialling a magnesium supplement to help with sleep with the standard dose for magnesium supplementation in the range of 200 to 400 mg per day.
Magnesium supplements are available in the form of magnesium oxide, magnesium malate, magnesium gluconate, magnesium chloride and magnesium citrate salts, as well as several amino acid chelates like magnesium aspartate. Gastrointestinal side-effects, like diarrhoea and bloating, are more common with magnesium oxide or magnesium chloride due to the lower absorption rates of these two forms. That is why magnesium oxide tends to be used as a laxative. Magnesium chloride is easily absorbed orally and used to treat heartburn, constipation, and low magnesium levels.
In general, magnesium citrate is a good choice for supplementation and is the most commonly used form of magnesium due to its high water solubility and bioavailability at around 25 to 30 percent. Magnesium bound to amino acids such as magnesium-aspartate also shows good levels of bioavailability but tends to be lesser than magnesium citrate.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.