Can magnesium-rich food aid athletic performance?

Are you deficient in a crucial mineral? Having low levels of the key mineral, magnesium, could be playing havoc with your life. One study of 8,000 Britons by Mineral Check discovered that around 70% had low levels. This topic was also discussed by Dr Michael Mosely on a Radio 2 interview.


A US Government National Diet and Nutrition survey also revealed that most children and adolescents fail to get the recommended daily allowance, with 53% of teenage girls showing levels of gross magnesium deficiency.

What is magnesium?

Magnesium is an essential mineral that our bodies need to work efficiently. It is used for more than 300 bodily functions and assists in energy production, maintaining healthy bone density and aiding the electrical conduction of the heart.

Magnesium is also an electrolyte because it conducts electrical signals in the body. It is needed in energy metabolism, glucose utilisation, protein synthesis, fatty acid synthesis and breakdown, also muscle contraction and all ATPase functions.

Magnesium is necessary for almost all hormonal reactions and in the maintenance of our cellular ionic balance.

How do I know if I am not getting enough magnesium?

Unfortunately, this is a mineral that does not show up well in most blood tests because it’s stored in your bones and muscles. So, looking at your daily diet and how you feel, is a better way to check if you might be short.

NHS Choices recommends the following:

  • 300mg a day for men (19-64 years)
  • 270mg a day for women (19-64 years)

Other sources cite up to 450mg is necessary, depending on body weight. For example, 5mg of magnesium per 2.2lbs of body weight i.e. a 150lb person would need 340mg per day. Needs also increase after age 30, especially for women, due to bone loss.

Magnesium is found in all of the body’s cells, although it is mostly concentrated in the bones, muscles, and soft tissues. An adult body contains around 25g of magnesium, with 50% to 60% present in the bones and most of the rest in our soft tissues.

Because less than 1% of our total magnesium is present in blood serum, it makes assessing our magnesium levels more difficult. Therefore, as stated, it is better to look to your normal dietary intake and lifestyle to assess your needs.

What are the signs of magnesium deficiency?

  • Heart abnormalities - magnesium deficiency results in altered cardiovascular function, including electrocardiographic abnormalities.
  • Insulin resistance and decreased insulin secretion (affects diabetes risk).
  • High blood pressure.
  • Even a mild deficiency can cause sensitivity to noise, nervousness, irritability, mental depression, confusion, twitching, trembling, apprehension, sleep disturbances, muscle weakness and cramps in the toes, feet, legs, or fingers.
  • Cravings for specific foods can indicate nutrient deficiency and if it’s chocolate you’re craving most often, a lack of magnesium could be the reason. For people who menstruate, our levels go down during and before our period. Dark chocolate can be high in magnesium and some experts suggest what we’re really craving when we long for chocolate pre-menstrually, is magnesium. The highest levels are found in dark chocolate that is over 60-70% cocoa.

How does magnesium deficiency happen?

Using refined oils and grains removes significant amounts from many packaged foods. Sadly, soil depletion from acid rainfall and climate change means less magnesium is available.

“Magnesium deficiency in plants is becoming an increasingly severe problem with the development of industry and agriculture and the increase in human population.”

- The Crop Journal Volume 4, Issue 2, April 2016

You could also be deficient because of the following:

  • Fertiliser use means less of the mineral is absorbed.
  • Drinking excessive amounts of water (runners not using electrolytes).
  • Not eating a balanced diet.

What can affect our magnesium levels?

Having a long-term health condition that affects the intestines such as IBS, Crohn’s disease or coeliac disease will alter how your body can store this mineral.

Diabetes leads to increased urinary losses of magnesium, and the subsequent magnesium inadequacy might impair insulin secretion and action, thereby worsening diabetes control. Unfortunately, only a few small, short-term clinical trials have examined the potential effects of supplemental magnesium on control of type 2 diabetes and the results are conflicting.

Magnesium levels may also be affected if you:

  • experience tummy bugs that cause sickness and diarrhoea
  • suffer from kidney disease
  • drink excessive alcohol or caffeine
  • sweat excessively e.g. during long-distance running

Magnesium and athletic performance

Athletes are pushing their bodies harder every day, making it even more important that they stay on top of their nutrient needs. Daily recommendations for an athlete’s magnesium are 320mg for women and 420mg for men - around 10-20% more than the average person (500-800mg appears to be safe).

Some research indicates getting enough magnesium into your diet may reduce exercise-induced inflammation, and some research suggests that supplementing with magnesium may increase athletic performance. However, further studies are required to back this up.

What are the signs of low magnesium in the body of an athlete?

  • muscle cramps
  • poor recovery from workouts
  • feeling down
  • poor sleep/always feeling tired. Magnesium is part of the body’s natural energy production system and contributes to energy release.
  • low energy levels and fatigue
  • headaches
  • unable to lose fat easily
  • eye twitches (this can also be due to low B12 levels)

Can magnesium enhance exercise performance?

Several studies evaluated the association between magnesium status/supplementation and exercise performance and found that the need for magnesium increased as individuals’ physical activity level went up.

The demand for magnesium is likely to increase during accelerated metabolic situations, thus, physically active individuals may have higher magnesium requirements to maintain optimal exercise performance, as compared with their inactive peers

Could magnesium help with weight-loss?

Some studies indicate this mineral could aid those wanting to lose weight. However, that does not necessarily mean that you will suddenly shed lots of pounds as soon as you start taking a supplement.

The good news is, though, it may help to improve pre-menstrual bloating. Studies have shown that magnesium may help regulate blood sugar and insulin levels in people who are overweight or obese.

A 2013 study found that taking higher amounts of magnesium helps better control insulin and glucose blood levels. The same study indicated that magnesium supplements might help reduce unpleasant menstrual symptoms in women because of their ability to reduce bloating and water retention.

What foods contain magnesium?

You could increase your intake of the following 10 magnesium-rich foods:

  1. pumpkin seeds
  2. chia seeds
  3. spinach
  4. cashews, dry or roasted
  5. white or black beans 
  6. avocados 
  7. almonds 
  8. banana 
  9. edamame beans
  10. 70% dark chocolate 

Magnesium supplements

Too much magnesium from food does not pose a health risk in healthy individuals because the kidneys eliminate excess amounts in the urine.

However, supplements deliver magnesium in a larger and more concentrated way than you’d get through regular foods, so there’s a possibility of negative side effects. These include:

  • tummy upset
  • diarrhoea
  • feeling sick
  • stomach cramps

It is possible to suffer from more serious symptoms if you have taken too many supplements, such as:

  • muscle weakness
  • low blood pressure or irregular heartbeat
  • very drowsy
  • particularly thirsty
  • breathing difficulties

It is also worth noting that magnesium could affect people who are on heart medications or taking diuretics or antibiotics.

If you are worried about getting enough nutrients and minerals from a balanced diet, contact a nutrition professional for advice.


  • Magnesium. (2016, February 11)
  • Hruby, A., Ngwa, J. S., Renstrom, F., Wojczynski, M. K., Ganna, A., Hallmans, G., … Nettleton, J. A. (2013). Higher magnesium intake is associated with lower fasting glucose and insulin, with no evidence of interaction with select genetic loci, in a Meta-Analysis of 15 CHARGE consortium studies. Journal of Nutrition, 143(3), 345-353
  • Diabetes Care.2010 Feb;33(2):304-10
  • DOI: 10.2337/dc09-1402. Epub 2009 Nov 10
  • Relations of dietary magnesium intake to biomarkers of inflammation and endothelial dysfunction in an ethnically diverse cohort of postmenopausal women.
  • Sara A Chacko 1, Yiqing Song, Lauren Nathan, Lesley Tinker, Ian H de Boer, Fran Tylavsky, Robert Wallace, Simin Liu
  • Run to the finish – Amanda Brooks
  • Nutrients.2017 Sept;9(9)946; Yijia Zhang, Pengcheng Xun, [...], and Ka He

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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Great Dunmow CM6 & Chelmsford CM1
Written by Hayley Smith, ANutr, MASC(Eating disorders/CBT), Dip (Sports Nutri), BA Hons Psy
Great Dunmow CM6 & Chelmsford CM1

I am a Registered Assoc Nutritionist. I work as a Nutritionist, Weight & Food-wellness coach from Great Dunmow & Springfield Hospital Chelmsford.

Specialisms include:
Weight Loss & Healthy Eating
Eating disorders & Weight gain
Sports Nutrition
Inflammation & Gut Health
Lowering blood sugar, cholesterol levels & cardiovascular risk

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