by Dr Jess Braid

a vital mineral, that we can all benefit from

Jess says: Magnesium is definitely one of my top three supplements, along with vitamin D and zinc. I have personally seen the difference that taking magnesium can do to benefit insomnia sufferers or poor sleepers in my patients (and myself). 

Magnesium is also my number one recommendation for anyone who exercises a lot or who suffers from cramp. It’s a wonderful mineral, and can make a massive difference to how you feel. A magnesium supplement is definitely worth considering if you have health problems or are pregnant. 

Magnesium levels can be measured on a blood test, but there are significant problems with the accuracy of a standard test. Magnesium levels are usually measured from the fluid of your blood (serum), yet most magnesium is stored either in our bones or inside our cells. A much better way to accurately measure magnesium levels is to have a red cell magnesium blood test done (this will have to be done privately, as it is not currently offered by the NHS).

Magnesium is vital for a wide range of critical systems in our body, but deficiency often goes undetected, as it is difficult to diagnose.

Up to 50% of people in the UK and USA have insufficient magnesium intake.We are only just beginning to understand the full range of benefits of magnesium. What we do know is that it is crucial in over 300 processes in the body; helping to make DNA, protein and energy. It’s essential for muscle contraction, blood sugar regulation, our heart function, blood pressure and nervous system.2

Magnesium levels in plants have dropped by up to 70%, since the 1950s. There has been a steep decline in the levels of magnesium in our soil, and therefore the naturally occurring level in the plants that are in our diet, over the past several decades.3 This is due to the industrialisation of farming and poor soil fertilisation.

Modern farming makes it harder for us to get enough magnesium in our diet. We know from the analysis of human remains that before industrialisation, we used to take in around 600mg/day of magnesium in our diet. Now, in developed countries, it is around 280mg/day – under half.4 Our soil has become more acidic, lower in nutrients and higher in toxins, over time. Organic and biodynamic farming produces food with more nutrients and antioxidants, and much lower levels of toxins.

Low levels of magnesium can cause muscle cramps. Leg and muscle cramp is a symptom of low magnesium levels. Taking in more magnesium, either through our diet or as a supplement, can significantly help to reduce the frequency and intensity of cramp, especially during pregnancy,5 when magnesium requirements are much higher (see below for more information on magnesium in pregnancy).

Low magnesium levels can cause heart issues. These include an irregular heartbeat and problems with nerve conduction. Low magnesium causes a range of abnormal heart rhythms, including atrial fibrillation and tachycardia (a rapid heart rate).6

Low magnesium has been associated with Alzheimer’s, diabetes and high blood pressure (hypertension). Magnesium is important in blood sugar regulation. Low levels have been shown to increase the risk of insulin resistance and type 2 diabetes. It may also worsen diabetic complications, and so should be strongly considered by diabetics.7 Poor blood sugar control in type 1 diabetics is also often seen in patients with low magnesium (or low chromium or zinc).8

Magnesium supplements have been shown to reduce blood pressure in those with high blood pressure.9 Animal studies show magnesium may protect against and improve Alzheimer’s disease.10

Low magnesium levels can increase the risk of migraine headaches and ADHD. Magnesium levels are often low in migraine patients and migraines were reduced in frequency, in patients taking magnesium supplements.11 12 Children with ADHD had a significant improvement in behaviour and hyperactivity when taking magnesium and vitamin B6, and symptoms became worse again when they stopped the supplements.13

Magnesium supplements may help sleep problems. There are several trials showing that magnesium supplements can significantly help to aid sleep problems, particularly in newborn babies and the elderly. 14, 15 It may also help those suffering from restless legs syndrome.16 Also consider supplementing with reishi mushroom, vitamin B12, practising gratitude and CBD oil, to help improve sleep.

Magnesium may help exercise performance and muscle cramps, and ease the symptoms of PMS. Magnesium has been shown to improve exercise performance, even in those who aren’t magnesium deficient and also in the elderly. 17 18 Magnesium and vitamin B6 supplements have both been shown to significantly improve symptoms of PMS.19

other benefits of taking magnesium supplements include:

  • Helping depression: Low magnesium levels are likely to contribute to depression.20 Taking a supplement may help.21
  • Magnesium supplementation in pregnancy may improve birth outcomes for the baby and reduce the chance of pre-eclampsia and levels of meconium. It can also help gestational diabetes. 22, 23, 24
  • May help bone density and osteoporosis. Low magnesium is associated with a lower bone density.25
  • Higher magnesium intake reduced the chances of dying from cancer, heart disease and all causes in a large study.26
  • Reduction in coronary artery calcification. Lower magnesium levels are associated with more incidence of heart disease.27
  • Magnesium supplementation significantly reduced the number and severity of seizures in patients with drug-resistant epilepsy.28
  • Low levels of magnesium can cause low levels of thyroid hormone.

the best natural sources of magnesium

The RDA for magnesium is 270-400mg per day. Magnesium deficiency occurs more commonly in those with bowel diseases and type 2 diabetes.

  • Almonds, dry roasted = 281mg, per 100g
  • Cashews, roasted = 292mg, per 100g
  • Pumpkin seeds = 262mg, per 100g
  • Peanuts, dry roasted = 176mg, per 100g
  • Spinach, boiled = 79mg, per 100g

ways to boost your magnesium levels

Eat more nuts and seeds. Some of the best sources of magnesium are nuts and seeds. Why not try our low-carb granola for a tasty treat, high in magnesium-rich ingredients?

Eat cooked spinach or swiss chard regularly. These green, leafy vegetables are easy to cook, just wilt briefly in a saucepan for a few minutes for spinach, or for eight minutes for swiss chard. These tasty veg are great with a pinch of nutmeg, butter and a squeeze of lemon juice.

Swap from milk to dark chocolate. Apart from its many other health benefits, high cocoa chocolate (more than 70% dark chocolate) is a great source of magnesium and far more preferable to sugary, high-calorie milk chocolate. Just one square of dark chocolate contains up to 95mg of magnesium.

dark chocolate

Drink kefir regularly.  Kefir contains 46mg of magnesium, per cup!

Epsom salt baths. Magnesium can be absorbed through the skin, and Epsom salts contain high levels. Adding one or two cups of Epsom salts to a warm bath regularly is traditionally thought to ease muscle cramps, aches and have a calming effect before bed.

Take a supplement. If you are very low in magnesium, consider taking a supplement. My favourites are ionic magnesium; a liquid that is particularly good at night to calm and soothe. It doesn’t taste the best, so try it diluted or in a warm bedtime drink, and chelated magnesium, which is very close to the same magnesium found in food and is very gentle. Magnesium glycinate, Magnesium bisglycinate or Magnesium threonate are the best chelated magnesium supplements and they are well absorbed. Magnesium citrate is also fine although it can have a laxative effect. 

Magnesium oxide is a cheap form of magnesium that contains the highest amount of elemental magnesium but is very poorly absorbed and can have multiple side effects. If you are planning on taking over 400mg of magnesium daily, please consult first with a functional medical practitioner. Be sure to follow the recommended dosage, when taking a magnesium supplement, as high doses can lead to diarrhoea and can be dangerous.

vitamin d supplement


My child suffers from restless leg syndrome, what can I do? 

The first step should be to see if increasing the magnesium in their diet from natural sources, like nuts and spinach can help their symptoms. If a balanced, magnesium-rich diet does not help, add some magnesium to their nighttime bath, with a cup of either Epsom salts or magnesium flakes. 

If you do want to use a daily magnesium supplement, try Nature’s Plus Animal Parade Mag Kidz chewable magnesium, which also comes as a powder in natural cherry flavour.  

Would you recommend using topical magnesium, like oil spray or lotion?

Magnesium is relatively well absorbed through the skin, so you can certainly try a topical spray (especially if you are getting muscle cramps) like the Better You spray, although it can be harder to work out the correct dosage, so be sure to follow the manufacturer guidelines. 


  1. Suboptimal magnesium status in the United States: are the health consequences underestimated?
  2. Magnesium in Prevention and Therapy
  3. Magnesium deficiency in plants: An urgent problem
  4. Magnesium deficiency in plants: An urgent problem
  5. Oral magnesium for relief in pregnancy-induced leg cramps: a randomised controlled trial
  6. Magnesium: the forgotten electrolyte
  7. Magnesium and disturbances in carbohydrate metabolism
  8. Chromium, zinc and magnesium status in type 1 diabetes
  9. The role of magnesium in hypertension and cardiovascular disease
  10. Elevation of brain magnesium prevents and reverses cognitive deficits and synaptic loss in Alzheimer’s disease mouse model
  11. Why all migraine patients should be treated with magnesium
  12. Role of magnesium in the pathogenesis and treatment of migraine
  13. Improvement of neurobehavioral disorders in children supplemented with magnesium-vitamin B6. I. Attention deficit hyperactivity disorders
  14. Serum magnesium level and sleep behavior of newborn infants
  15. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial
  16. Magnesium therapy for periodic leg movements-related insomnia and restless legs syndrome: an open pilot study
  17. Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation
  18. Effect of oral magnesium supplementation on physical performance in healthy elderly women involved in a weekly exercise program: a randomized controlled trial
  19. Evaluating the effect of magnesium and magnesium plus vitamin B6 supplement on the severity of premenstrual syndrome
  21. Magnesium and depression: a systematic review
  22. An evaluation of serum magnesium status in pre-eclampsia compared to the normal pregnancy
  23. Magnesium supplementation affects metabolic status and pregnancy outcomes in gestational diabetes: a randomized, double-blind, placebo-controlled trial
  24. Magnesium in pregnancy
  25. Magnesium intake, bone mineral density, and fractures: results from the Women’s Health Initiative Observational Study
  26. Magnesium intake, bone mineral density, and fractures: results from the Women’s Health Initiative Observational Study
  27. Magnesium intake is inversely associated with coronary artery calcification: the Framingham Heart Study
  28. Magnesium as an effective adjunct therapy for drug resistant seizures