Athletes Essentials – Magnesium

Magnesium is essential to all cells, acting as a cofactor for the activity of more than 300 enzyme systems. After potassium, it’s the second most abundant mineral found in the human body. Roughly one quarter is found in muscle tissue, approximately three fifths in bone, and less than 1% found in the blood serum, which surprisingly is the most commonly used indicator of magnesium levels (Nica et al., 2015).


A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation.


Magnesium is surrounded by two hydration shells. Intracellular magnesium concentrations range from 5 to 20 mmol/L; 1–5% is ionized, the remainder is bound to proteins, negatively charged molecules and adenosine triphosphate (ATP).


Magnesium plays a vital role in helping regulate biochemical reactions in the body, including blood glucose, blood pressure, muscle function and protein synthesis. From an exercise performance perspective, magnesium is also needed for the production of energy, oxidative phosphorylation, and glycolysis. It also plays a vital role in the transport of calcium and potassium ions which are essential for muscle contraction. With its presence necessary for both aerobic and anaerobic energy production (Office of dietary supplements – magnesium, 2016).


There are numerous studies suggesting the positive outcomes from supplementing magnesium within the field of sports and exercise performance. However given that 60% of the general population in the US have been identified as magnesium deficient (DRI, Dietary reference intakes, 1997), the real debate is to whether additional magnesium supplementation is actually improving performance or is simply aiding athletes to reach their recommend levels, because they are magnesium deficient (DRI, Dietary reference intakes, 1997). What is clearly supported from numerous studies, is that magnesium deficient impairs performance and amplifies the negative consequences of strenuous exercise (e.g., oxidative stress). This is likely to be a result of reduced oxygen efficiency, therefore increasing the amount of oxygen required to maintain ATP production (Bergstrom and Hultman, 1988).


According to the UK food standards agency/COMA, the calculated recommended daily requirement is 300 mg for adult males and 270 mg for adult female. The recommended daily requirement for infants and children ranges from 55 to 280 mg/day (cot.food.gov.uk, 2003). With the US recently increasing their daily recommendation to 400 mg for adult males and 300 for females (Institute of Medicine, 1997).


One study identified that taking 350 mg·d–1, for a period of 4 weeks, showed significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump (Setaro et al., 2013). Furthermore the study also concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient (Setaro et al., 2013).


A second study using 300 mg·d-1 magnesium oxide supplementation, also identified positive health indicators, with decreases in systolic blood pressure, pre and post exercise, in as little as two weeks of magnesium supplementation. However the study also concluded that they found no significant difference within both: strength tests and aerobic performance (S. Kass, Skinner and Poeira, 2013).


A third study supplementing 10 mg/kg/d magnesium for a period of 4 weeks, suggested that magnesium supplementation positively influences the performance of training athletes by increasing erythrocyte and haemoglobin levels (Cinar et al., 2007).


Conversely, a recent study highlights the key factors identified by insufficient levels of magnesium, which is especially important within high performing athletes, due to the nature of their sporting demands, require an even greater amount of magnesium intake. This could be explained by the important role of magnesium in energy metabolism, transmembrane transport, and muscle contraction and relaxation (Santos et al., 2011).


Given the amount of recent and relevant studies and literature recording the benefits of magnesium supplementation, there is clear evidence supporting the use within both athletic performance and in general. The dose is some what a grey area, as people have different levels from dietary intake and exercise. However, on average, most people are deficient (DRI, Dietary reference intakes, 1997). One study suggests supplementing somewhere between 300- 900 mg daily by slowly increasing the amount over a course of weeks until stools become too loose. Then reduce back to a suitable level. Other studies simply suggest supplementing 300-350 mg daily (Setaro et al., 2013)(S. Kass, Skinner and Poeira, 2013). The source of Magnesium supplementation has also been studied, and produced mixed results. The inexpensive oral supplements of magnesium generally contains magnesium oxide, which is poorly absorbed (4%). Magnesium citrate is much better absorbed (50%), but is not so cheap. Out of a daily intake of 300-400 mg elemental Mg, only an amount of 12-16 mg can be used (the ionized form). A few studies showed that soluble preparations are generally better absorbed and magnesium aspartate, citrate, lactate and chloride have a superior bioavailability compared to magnesium oxide and sulphate (Firoz and Graber, 2001).


OK, so thats a brief summary of some of the science, research and up-to-date literature on Magnesium Supplementation. I think the results speak for themselves. With such performance increases it would only be advisable that any athlete that is currently competing and/or training a higher-level should really consider the use of Magnesium Supplemention. Personally I have found the greatest benefits from taking a high quality ZMA (Zinc, Magnesium, Vit B6) at night prior to sleeping, with magnesium clearly being the greatest benefit. In addition, I also regularly use Epson Bath Salts when my body is feeling particularly beaten-up, as magnesium has been shown to work well through absorption directly into the muscles, hence the sudden onset on Magnesium rubs and creams (be careful with these as the dosage is often way too low). Whatever method wether that be ingestion or absorption it needs to be on a regular and consistent basis to receive any sort of benefits and the quality/quantity also need to be right. Be sure to check the ingredients and do your research before giving over your pennies.


For the naturalists out there, here are a few things that contain higher levels of magnesium if supplements are not an option.

Brazil Nuts

Halibut

Cocoa

Rice Bran

Cashews

Quinoa

Pumpkin Seeds

Almonds

Spinach


Written by Alex Rees BSc Hons Strength and Conditioning


References

Bergstrom, M. and Hultman, E. (1988). Energy cost and fatigue during intermittent electrical stimulation of human skeletal muscle. Journal of Applied Physiology, 65(4), pp.1500-1505.

Cinar, V., Nizamlioglu, M., Mogulkoc, R. and Baltaci, A. (2007). Effects of magnesium supplementation on blood parameters of athletes at rest and after exercise. Biological Trace Element Research, 115(3), pp.205-212.

cot.food.gov.uk. (2003). Safe Upper Levels for Vitamins and Minerals. [online] Available at: https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf [Accessed 5 Apr. 2017].

DRI, Dietary reference intakes. (1997). 1st ed. Washington, D.C.: National Academy Press.
Firoz, M. and Graber, M. (2001). Bioavailability of US commercial magnesium preparations. Magnes Res, 14(4), pp.257-62.

Institute of Medicine (IOM) (1997). Food and Nutrition Board. Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride Washington, DC: National Academy Press. Publication (PDF): Magnesium supplementation in top athletes – effects and recommendations. Available from: https://www.researchgate.net/publication/275335093_Magnesium_supplementation_in_top_athletes_-_effects_and_recommendations [accessed Apr 5, 2017].

Jahnen-Dechent, W. and Ketteler, M. (2012). Magnesium basics. Clinical Kidney Journal, 5(Suppl 1), pp.i3-i14.

Nica, A., Caramoci, A., Vasilescu, M., Ionescu, A., Paduraru, D. and Mazilu, V. (2015). Magnesium supplementation in top athletes – effects and recommendations. Journal of the Romanian Sports Medicine Society, vol. XI(no 1), pp.2482-2494.

Office of dietary supplements – magnesium (2016) Available at: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/#en3 (Accessed: 18 February 2017).

Santos, D., Matias, C., Monteiro, C., Silva, A., Rocha, P., Minderico, C., Sardinha, L. and Laires, M. (2011). Magnesium intake is associated with strength performance in elite basketball, handball and volleyball players. John Libbey Eurotext’s, 24(4), pp.215-9.

Setaro, L., Santos-Silva, P., Nakano, E., Sales, C., Nunes, N., Greve, J. and Colli, C. (2013). Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation. Journal of Sports Sciences, 32(5), pp.438-445.

S. Kass, L., Skinner, P. and Poeira, F. (2013). A Pilot Study on the Effects of Magnesium Supplementation with High and Low Habitual Dietary Magnesium Intake on Resting and Recovery from Aerobic and Resistance Exercise and Systolic Blood Pressure. Journal of Sports Science and Medicine, 12, pp.144 – 150.

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