Why is Magnesium so vital for overall body function and performance?

Magnesium is required by millions of cells in the body to carry out a range of very important biochemical processes every day. Magnesium is involved in the metabolism and break down of the foods we consume, muscle and nerve function, bone health, nervous system and sleep regulation.

One of Magnesium’s main processes in the body is energy production, the metabolism and break down of the foods we consume to be converted into energy. This is extremely important when it comes to exercise, exercise performance and body composition as inadequate amounts will impact how well your body breaks down glucose and how it is used in the body.

Poor glucose and protein metabolism can be a key player in your exercise performance, impacting how well you drop weight with your body not able to use your energy as effectively as possible. Poor glucose metabolism can also lead to lack of energy and fatigue, impacting the quality and quantity of your exercise with fatigue setting in reducing how well you perform during exercise.

Magnesium is involved in many processes that affect muscles and nerve function, helping muscle fibres to relax, relieving and assisting in the prevention of muscular cramps and spasms. If magnesium is being depleted quicker than it is being replenished then muscle fibres are able to contract but struggle to relax, leading to prolonged contraction.

So how much Magnesium does the body need?

The Recommended dietary intake (RDI) for aged 19 years & above is 310 -320 mg/day for females and 400- 420 mg/day for males. Magnesium rich food sources include almonds, boiled spinach, cashews, black beans, cacao, avocado, plain yoghurt, peanuts, kelp, figs, salmon and edamame beans.

Consuming a handful of almonds along with a spinach avocado salad with a few pieces of dark chocolate doesn’t seem hard to consume daily. So why is a big part of the population lacking in magnesium, when it seems so easy to consume through everyday foods?

33% of the Australian population do not meet their daily magnesium requirement, but why is this? The amount of magnesium absorbed into the body is dependent of many various factors. These factors include:

  • Dietary intake
  • Soil quality
  • Stress levels
  • Caffeine, alcohol & tea intake
  • Supplementation – Types & form of magnesium
  • Medication
  • Compromised gut health – poor absorption
  • Exercise- excess sweating

Picture – www.blackmores.com.au

Coffee and tea contain tannins which affect the absorption of magnesium, along with the caffeine having a diuretic effect on the body increasing the loss of water and minerals through urination. Alcohol and medication also have the same diuretic effect, in addition to the body using up more magnesium to try process and excrete alcohol from the body.

Electrolyte balance in the body relies on adequate amounts of magnesium to support the transportation of vitamins and minerals such as calcium and potassium across the cell membrane. Exercise causes sweat loss and increased urination with minerals being excreted along with fluids, influencing electrolyte balance in the body.

Stress plays a role in regulation of magnesium in the body with ongoing stress depleting magnesium levels, then with low levels of magnesium leading to more heightened stress levels. This cycle can not only lead to depleted magnesium levels but can start impact energy levels, sleep and mood regulation.

What is the best Magnesium supplement?

There are many forms of magnesium supplements on the market and choosing the best supplement for you can be daunting and confusing, with different magnesium supplements indicated for different health conditions.

As magnesium alone is not well absorbed in the body, magnesium in supplements is bound to a transporting substance for better absorption.

An optimal form of magnesium that is readily available and well absorbed in the body is magnesium glycinate, bis- glycinate or di- glycinate. Not only is this form well absorbed but is less likely to cause laxative side effects and digestive discomfort.

Other well absorbed forms include chelate, citrate, orotate, and threonate, though threonate is not as readily available to purchase and citrate at high doses can cause a laxative effect.

Most magnesium supplements will contain other vitamins and minerals which support absorption and are needed for the body to use magnesium efficiently. Powder forms of magnesium are generally absorbed quicker and better with some examples of good quality magnesium supplements below.

  • Orthoplex – Mag Taur Xcell (Practitioner formula)
  • Metagenics – Calmx (Practitioner formula)
  • Swisse- High Strength Magnesium Powder
  • Ethical Nutrients – MegaZorb Magnesium

** Practitioner range supplements can only be prescribed by a qualified health care practitioner with a consultation.

Some forms are poorly absorbed and not well tolerated in the body, by drawing water to the bowel leading to unfavourable side effects of diarrhoea resulting in poor magnesium absorption and higher excretion through urine. If you suffer from digestive discomfort and loose stools then avoiding forms such as magnesium carbonate, chloride, oxide and gluconate.

How to meet your RDI of Magnesium?

  • 1 Cup spinach – 157 mg
  • 1 Cup black beans – 150 mg
  • 1 Cup swiss chard – 150 mg
  • ¼ Cup almonds – 97 mg
  • ¼ Cup cashew – 91 mg
  • 1 Whole avocado – 39 mg
  • 1 Cup broccoli – 32 mg

There are many possible reasons to why you may be lacking in magnesium but starting with looking at your diet is the first step. Drinking your coffee and tea away from your meals along with cutting back the amount of caffeine you are consuming each day. Fill your plate up with dark green leafy vegetables and try to have at least one serving of nuts and seeds each day to ensure you are replenishing your magnesium needs daily.

If you are looking for personalised supplementation advice, get in touch with our in house Speedfit Nutritionist to discuss supplements which will better support your diet, lifestyle and helping to avoid any unwanted side effects.


Australian Bureau of Statistics. Australian Health Survey: Usual Nutrient Intakes, 2011-12 [Internet]. 2015 [updated 2015 Apr 27; cited 2019 Feb 11]. Available from: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.008~2011-12~Main%20Features~Magnesium~406




Nielsen, F, Lukaski, H. Update on the relationship between magnesium and exercise. Magnesium Research. 2006. [cited 2019 Feb 11]. 19(3): 180-9. DOI: 10.1684/mrh.2006.0060