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TRI Fitness Blog


Dec 01, 2015

Have you ever suffered from muscle spasms whilst training and wondered why? You've been nailing a swim or powering up a hill on the bike and you cramp? Chances are, that if you have, you might not be including enough magnesium in your diet. It can be difficult to get enough of this mineral in your diet, especially if you don't include a huge amount of whole grains, cereals, green leafy veg or nuts and seeds. Added to this, high sugar intake, alcohol consumption and diets with a high amount of fat, protein and calcium can inhibit magnesium absorption. Even if you are nailing your nutrition, if you are highly active your body will require more magnesium which puts you at risk of depletion. Lets take a look at what this mineral is all about.

The Facts

Magnesium is the second most common cation found in the body (Nutri Advanced 2015). There is approximately 25g of magnesium distributed between the skeleton (50-60%) and soft tissues (40-50%) allowing it to regulate diverse chemical reactions as a cofactor in more than 300 enzyme systems in the body (Cashman 2009).

Magnesium is in part, responsible for the development and maintenance of the structural integrity of bones and teeth. It is required for the active transport of calcium and potassium ions across cell membranes, nerve conduction, muscle contraction and normal heart rhythm (McGarrigle 2015) making it all the more fundamental to athletic performance. Magnesium has also been shown to enhance the condensation of chromatin and is therefore required for the synthesis of DNA, RNA and the antioxidant glutathione, needed for detoxification (Cashman 2009). Last but not least, magnesium is associated with protein synthesis, blood glucose control, hormonal balance and blood pressure regulation (McGarrigle 2015). This makes magnesium an essential nutrient for reaching and maintaining any desired weight goals too!

Deficiency Signs & Symptoms

Resent data from the UK National Diet and Nutrition Survey (2008/2009-2011-2012) showed intakes of magnesium to be below the recommended intake in both adults and children (Public Health England 2014).  Low levels of magnesium have been associated with diseases such as Alzheimer’s disease, type-2 diabetes, hypertension, strokes, migraine headaches, eclampsia, preeclampsia, osteoporosis and attention deficit hyperactivity disorder (Gröber U 2015).

Deficiency is characterized by:

  • Muscle spasms
  • Restless legs
  • Bronchospasms
  • Cramps
  • Seizures
  • Anxiety
  • Arrhythmia
  • Migraines
  • Insomnia
  • Depression
  • Chronic fatigue
  • Reduced plasma magnesium
  • Hypocalcemia or hypocalciuria

(McGarrigle 2015)

Therapeutic Uses


Many studies support the role of magnesium for blood pressure regulation and its use in the treatment of cardiac and vascular disorders (Altura BM 1985). Research suggests that it should be considered as a treatment choice for hypertension due to its role in cell membrane permeability for sodium and calcium in order to prevent the development of resistant hypertension and arrhythmias. It has been suggested that magnesium therapy may also reduce blood pressure (Singh RB 1989).


Short-term magnesium sulfate therapy following childbirth has been shown in studies to prevent convulsions in severe preeclampsia (Anjum S 2015).


Magnesium can be taken orally as a laxative for constipation or to prepare for medical procedures although long term use should be avoided due to risk of toxicity (Mounsey A 2015).


Magnesium is used to treat short-term dyspepsia and has been shown to reduce heartburn. Various varieties of magnesium are used singularly or in combination with other medication such as PPI’s and activated charcoal (Coffin B 2011).

Dietary Sources








Pumpkin seeds



Swiss chard






Kidney beans



Brown rice









(The George Mateljan Foundation, 2015)

Reference Nutrient Intakes

Adult males 300mg per day

Adult females 270-300mg per day

Pregnancy: 270mg per day

(Family food statistics 2014)

Should I supplement? 

Ideally you should be looking to get enough magnesium through the food you eat. Magnesium bound organically in whole food form is easily absorbed by the body. Even a simple change like eating a handful of magnesium rich pumpkin seeds per day can make a difference. Where supplementation is preferred, magnesium is cheap & unlikly to be toxic so an insurance policy might be worth the while. Magnesium in supplement form must be bound to another mineral such as citric acid, ascorbic acid or malic acid (McGarrigle 2015). Magnesium is best absorbed in small, frequent doses; so, for example, it is better to take 100mgs three times a day than 300mgs in one go!

If you are looking to buy from TRI Fitness, we stock two types of magnesium:

Phil Richards Alkalizing Salts: contains 900mg/5g powder of magnesium carbonate in combination with sodium, potassium and calcium at 900mg per 5g of powder.

Phil Richards Magnesium Relax: contains 175mg magnesium taurate, 175mg magnesium glyccinate and 175mg magnesium malate. This combination has been specially formulated by Phil Richard and his team of experts to help induce relaxation, ease anxiety and relax muscles.

See our shop for more info:

Toxicity Level and Symptoms

As a naturally occurring substance in food, no adverse effects of magnesium are seen so long as renal function is normal. Adverse effects may be seen where high doses of inorganic magnesium are taken causing symptoms such as diarrhea, nausea, gastric irritation and abdominal cramping. .

Interactions with Other Nutrients


  • Aminoglycoside may interact as they compete with magnesium in skeletal muscle and could cause muscle problems.
  • Magnesium is thought to stop Quinolone antibiotics from being absorbed. Where supplementation is required, they should be ingested at least 2 hours after.
  • Magnesium can attach to Tectracycline antibiotics in the stomach thus decreasing the amount of antibiotic that the body can absorb. 


  • Magnesium reduce absorption of bisphophonates and must therefore be taken two hours pre/post medication (WebMD 2015).

Blood pressure:

  • Magnesium has been associated with the reduction of blood pressure. Blood pressure medication and magnesium supplementation could cause too low a blood pressure decrease (Singh RB 1989).


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