What does magnesium do?

From restful sleep to strong bones and migraine relief, this mineral is vital for good health

Why do we need it?

Mainly stored in our bones, the mineral magnesium helps us turn our food into energy, and helps our bodies produce hormones that are important for bone health. It plays a role in more than 300 enzyme systems that regulate blood glucose control and blood pressure, among other things. It’s also key for nerve function, muscle activity and heart rhythm. Pretty important, then.

Where can we get it?

A good rule of thumb is that foods high in fibre also tend to contain magnesium. Green, leafy veg such as spinach and kale, vegetables such as broccoli and squash, nuts (especially almonds), seeds, cereals and legumes are all good sources. Dairy products, chocolate and coffee can provide a little magnesium, and tap water also contains the mineral, particularly if it’s hard water. If you think your levels might be low, you might want to consider a magnesium supplement, which can be taken in the form of a capsule, tablet or transdermal spray.

Any research behind it?

There’s plenty, for all kinds of health benefits.

Eases sleep trouble

Magnesium is often touted as a remedy for sleepless nights, and there’s evidence behind this claim. One double-blind, placebo-controlled clinical trial – the gold standard in research – compared the effects of a magnesium supplement with a placebo among elderly people with insomnia. Participants received either a placebo or 500mg of magnesium for eight weeks and kept a record of the severity of their insomnia during this period. The magnesium group slept for longer, produced more of the sleep hormone melatonin, took less time to drop off, had less of the stress hormone cortisol in their bloodstream, and didn’t wake up so early. In other words, they slept better and for longer.

Reduces type 2 diabetes

It’s common for diabetics, both type 1 and type 2, to be deficient in magnesium. Research has shown that increasing consumption of magnesium-rich foods such as wholegrains, beans, nuts and green, leafy vegetables may reduce risk of type 2 diabetes. Guidelines from the Association For Magnesium Research suggest that diabetes patients would benefit from taking a 240-480mg magnesium supplement daily.

Helps heart health

Evidence from studies on populations have found that higher magnesium intake – whether that’s thanks to a good diet or taking a regular supplement – helps to protect against major cardiovascular problems including high blood pressure, stroke and heart disease. A 2018 review concluded that ‘the current evidence supports the importance of adequate dietary magnesium for lowering the risk of cardiovascular disease’.

Prevents migraines

Another trial compared a placebo with a supplement containing magnesium, riboflavin and coenzyme Q10 as a treatment for migraine among 130 people. They took it for three months, then researchers analysed migraine frequency, level of pain and impact on daily life. Among the magnesium group, migraine days per month were reduced by nearly a third (from 6.2 days to 4.4), pain intensity reduced and the score for impact on life went down by 4.8 points (compared to two points in the placebo group).

Who requires more of it?

Research shows that, since 1940, our foods have contained less magnesium; there’s been a 38 per cent drop in cheddar cheese, 21 per cent in whole milk and 24 per cent in vegetables. Since 1968, the content in wheat has dropped almost 20 per cent, too – so we all need to work a bit harder to get enough. The magnesium content of bone decreases with age, so it’s important older people get enough through their diet, especially as the most recent National Diet And Nutrition Survey found that 65-74-year-olds were lacking.

How much do I need?

According to the NHS, women should get 270mg a day. Be careful of taking a high dose magnesium supplement (more than 400mg), as it can cause diarrhoea. However, regularly taking 400mg or less is unlikely to cause you any harm. Magnesium can also interfere with some medications for things such as blood pressure, muscle relaxants and certain antibiotics, so check with your doctor first.

If you are breast-feeding, pregnant or under medical supervision, check with your GP before taking supplements.