Benefits Of Magnesium: What You May Not Know About This Super Supplement

Dr Jess cardiology, endocrinology, Garden, musculoskeletal, Natural Fixes, Neurology, obstetrics, psychiatry, sleep, sports medicine

Dr Jess says: This is definitely in my top 3 supplements with Vitamin D. I have seen magnesium significantly improve sleep in many of my patients (and myself!) and it is my number one recommendation for anyone doing a lot of exercise or suffering from cramp.

A wonderful mineral that can make a massive difference to how you feel and 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 the standard test.

Magnesium levels are currently usually measured from the fluid of your blood (serum) and most magnesium is either in your bones or intracellular (inside our cells). A much better test is to have a red cell magnesium blood test done, this is not offered by the NHS.

This mineral 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 & US have insufficient magnesium intake (1)…

This is concerning as we are only just beginning to understand the benefits of magnesium. We do know it is crucial in over 300 processes in the body; helping make DNA, protein and energy. It is 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 plants in our diet over several decades (3). This is due to industrialisation of farming and poor fertilisation of soil.

Modern farming makes it harder for us to get enough magnesium in our diet…

We know from analysis of 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 can cause muscle cramps…

Leg and muscle cramp is a symptom of low magnesium and magnesium can significantly help cramp especially during pregnancy (5) when magnesium requirements are much higher (see other benefits below for more information on magnesium in pregnancy).

An irregular heartbeat and problems with nerve conduction…

Low magnesium causes a range of abnormal heart rhythms including atrial fibrillation and tachycardia (fast heart rate) (6).

Low magnesium has been associated with Alzheimer’s, diabetes and high blood pressure (hypertension)

Magnesium is important in blood sugar regulation and 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 (6) (or low chromium or zinc).

Magnesium supplements have been shown to reduce blood pressure in those with high blood pressure (8). Animal studies show magnesium may protect against and improve Alzheimer’s disease (9).

It can also increase the risk of migraine headaches and ADHD…

Magnesium levels are often low in migraine patients (10) and migraines were reduced in frequency in patients taking magnesium supplements (11). Children with ADHD had a significant improvement in behaviour and hyperactivity when taking magnesium and B6, and symptoms became worse again when they stopped the supplements (12).

Magnesium supplements may help sleep problems…

There are several trials showing that magnesium supplements can significantly help sleep problems, particularly in newborn babies (13) and the elderly (14), and it may help those with RLS (restless legs syndrome) (15). Also consider reishi mushroom, vitamin B12, practising gratitude and CBD oil for aiding sleep.

They 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 deficient (16) and in the elderly (17). Magnesium and B6 supplements have both been shown to significantly improve symptoms of PMS (18).

Other benefits of supplements include:

  • Helping Depression – Low levels likely contribute to depression (19) and supplements may help (20).
  • Pregnancy – May improve birth outcomes for the baby and reduce the chance of pre-eclampsia (21) and meconium. It can also help gestational diabetes (22), (23).
  • May help bone density and osteoporosis – Low magnesium is associated with a lower bone density (24).
  • Reducing your chance of dying – Higher magnesium intake reduced chance of dying from cancer, heart disease and all causes in a large study (25).
  • Reduction in coronary artery calcification – lower magnesium levels are associated with more heart disease (26).
  • Seizures – Magnesium supplementation significantly reduced the number and severity of seizures in patients with drug-resistant epilepsy (27).
  • Hypothyroidism – Low levels of magnesium can cause low levels of thyroid hormone – read more about natural supports for the thyroid here.


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

The top 5 sources of Magnesium in order are:

  • 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)


Eat more nuts and seeds – As you can see above 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 foods?

Eat cooked spinach or swiss chard regularly – These green leafy vegetables are easy to cook, just wilting in a saucepan briefly for 2-3 minutes (spinach) or 8 minutes (swiss chard) with a small amount of water. They are great with a pinch of nutmeg, butter and a squeeze of lemon juice. Delicious and incredibly simple.

Swap milk to dark chocolate – Apart from its many other health benefits, high cocoa (>70% dark chocolate) is a great source of magnesium and far more preferable to the sugary and high calorie milk chocolate. Just 1 square of dark chocolate contains up to 95mg of magnesium.

Drink kefir yoghurt regularly – Yet another reason to drink kefir, this amazing superfood is also high in magnesium at 46mg per cup!

Epsom salt baths – Magnesium can be absorbed through the skin and epsom salts contain high levels so adding 1-2 cups 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 favourite are ionic magnesium (a liquid which is particularly good at night to calm, although it tastes unpleasant so dilute or mix) and chelated magnesium (similar to food magnesium and very gentle).

Magnesium oxide is a good version of magnesium which contains a high level of magnesium at around 60% elemental magnesium. Discuss levels over 400mg daily of supplementation with a functional medical practitioner. (Follow recommended doses of magnesium as high doses can lead to diarrhoea and can be dangerous).