What is magnesium and why do we need it?

Whether you consume it through your diet, pop it in a pill, or luxuriate in it in a warm Epsom salts bath, magnesium is essential for numerous functions in the body.

Involved in more than 600 enzyme reactions in the body, it is important for protein synthesis, muscle and nerve function, blood glucose control, regulating blood pressure, energy production, bone health, synthesis of DNA, transportation of calcium and potassium, and for metabolisation and synthesis of vitamin D.

Evidence suggests it is also beneficial for heart health, and protective against bowel cancer.

5 health benefits of magnesium

1. Restlessness and cramping

Magnesium supplements are often taken to tackle cramping or restless legs syndrome. However, although a small study found magnesium supplementation may be worth further investigation for these issues, more recent clinical trials have found it to be no better than a placebo.

2. Mental health

According to one study, magnesium may also support mental health by helping to alleviate signs of depression.

In a randomised crossover trial of 126 adults in outpatient primary care clinics, it was found that supplementing with magnesium chloride for six weeks resulted in a clinically significant improvement in measures of depression and anxiety symptoms, with positive effects showing quickly at two weeks.

However, while results were “very encouraging”, further studies were needed in a larger, more diverse population.

If the body has an inadequate supply or poor access to magnesium then we find that energy production is limited, leaving an individual feeling fatigued or exhausted

3. Energy

Exercising with low magnesium levels may cause the body to work harder — but not in a desirable way — putting greater demand on oxygen and energy needs.

One small study found that when a group of women exercised while low in magnesium, they used more oxygen and had increased heart rates.

Rebecca Warren, a registered nutritional therapist, also adds: “If the body has an inadequate supply or poor access to magnesium then we find that energy production is limited, leaving an individual feeling fatigued or exhausted.”

4. Bone health

Magnesium in drinking water may help to protect against fractures, according to a study from Norway, which at the time of the study had one of the world’s highest rate of hip fractures.

Researchers created a registry of hip fractures and a map of the various water utility companies in the country. Drawing on data for trace metals in the water, they were able to compare the number of hip fractures against the areas with the highest and lowest areas of calcium and magnesium in drinking water.

A correlation was found between relatively high levels of magnesium and lower rates of hip fractures in both men and women, but no such correlation was found with calcium.

The study’s authors said that although the protective effect of magnesium was “unsurprising”, the correlation between calcium and magnesium in water and hip fracture was complex. They said further research was needed to better understand the biological mechanisms involved.

5. Vitamin D

Magnesium has been found to be essential for metabolising and regulating vitamin D, increasing or lowering active vitamin D levels as necessary.

Magnesium deficiency has been found to reduce the ability of enzymes to synthesise vitamin D and convert it into the active form that the body can use.

How can I get enough magnesium?

We should be able to get all the magnesium we need through a varied and healthy diet. Reference nutrient intakes (the amount considered necessary to maintain healthy levels) are 300mg and 270mg per day for men and women, respectively.

“Magnesium is available in a wide variety of healthy ingredients so getting in your daily dose doesn’t have to be difficult,” says Warren.

“[However] a great number of factors affect magnesium bioavailability, including factors such as nutrient filtration by the kidneys and varying levels of absorption caused by age, stress, certain diseases and individual differences.”

Food sources of magnesium:

  • Seeds such as pumpkin and chia
  • Green leafy vegetables such as spinach
  • Nuts such as almond, cashew
  • Legumes such as peanuts, kidney beans
  • Wholegrains, such as brown rice, whole oats
  • Yoghurt
  • Tofu
  • Salmon
  • Chicken
  • Dark chocolate

What about supplements?

According to the NHS, taking high doses of magnesium (more than 400mg) for a short time can lead to diarrhoea, but there is insufficient evidence to say what the effects might be of taking high doses for a long period of time.

Warren says not everybody needs to supplement magnesium but for those who do, she says magnesium citrate and magnesium glycinate are considered good options because gastrointestinal side effects (“hello, bathroom!”) are more common with magnesium oxide or magnesium chloride.

She also recommends taking a bath with Epsom salts, which allows magnesium to be absorbed through the skin.

However, it is always recommended to take supplements under the guidance of a registered nutritional therapist or GP.

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