Episode 58 - What’s the deal with magnesium? | Dr Sophie Killer

Fueling Endurance - Nutrition for Runners, Cyclists & Triathletes

It seems every second runner, cyclist or triathlete you meet is taking, or talking about, magnesium. Ask them why and you often get some vague kind of answer - for recovery, for muscle function, or something a bit more specific like cramping.

But when you delve into the sports nutrition guidelines, there’s no mention of magnesium in there. Literally nothing. So are athletes a step ahead of the science here, or have they been duped by the lure of a supplement that uses terms like “nervous system” and “muscle function” that are taken from a symptom list of clinical magnesium deficiency?

In today’s episode, we’re joined by Dr Sophie Killer, a sports nutritionist and researcher who did some of the very few studies of magnesium and athletes during her time working with UK Athletics. We’ll look at what magnesium does in the body, how to know if you’re deficient in magnesium, whether deficiency is common in athletes, whether supplements can improve performance or reduce cramping, the benefits and risks of magnesium supplementation, and whether we should think about magnesium as a daily supplement like iron, or something that specifically needs replacing during exercise like sodium.

Sophie's study looking at magnesium testing in UK track and field athletes over an 8 year period: https://doi.org/10.1080/07315724.2019.1691953