Micronutrient myths: vitamins, nitrates and magnesium – should you take supplements?

When you’re attempting to push your body to the limit, it’s vital that you watch what you eat and make sure you have enough of the right stuff to keep going.  We are often told we need to supplement our micronutrient intake, with commonly touted micronutrients including vitamin supplements, nitrates and magnesium.  So should you really be supplementing these?  Or are they just a waste of your money?

Unfortunately the reasons we’re often given to supplement our vitamin intake come from an academic basis, and it hasn’t translated into any real clinical significance.



Vitamins are nutrients that are required for normal functioning, in limited amounts.  For a compound to be considered a vitamin, it must not be able to be synthesised by our bodies and therefore has to obtained from our diets or lifestyles.  As a healthy person, with certain exceptions, you generally shouldn’t be supplementing your vitamin intake, but can they improve performance in endurance athletes?  Well, before reading any research, it’s important to know if the distinction the authors are drawing is academic or clinical.  An academic conclusion means there is a sound biochemical basis, explaining why this compound will aid in recovery or any other function.  A clinical conclusion is one that actually results in a perceivable difference. Unfortunately the reasons we’re often given to supplement our vitamin intake come from an academic basis, and it hasn’t translated into any real clinical significance (1).  Studies into the efficacy of vitamins in athletes shows tenuous evidence at best, and at worst, a detrimental effect. What the evidence does conclusively show is that a deficiency worsens exercise performance, so be sure to eat a healthy balanced diet to keep your levels where they need to be, but you probably don’t need to bother with expensive supplements.

Beetroots (nitrates)


Taste great, but unfortunately don’t help you perform better.

Beetroots are high in nitrates (NO3-), a similar compound to one given by cardiologists to hypertensive patients with chest pain.  Gylceryl Trinitrate (GTN), is a pro-drug which, upon metabolisation by your liver, is converted to nitric oxide, a potent vasodilator, meaning it is a compound which dilates your blood vessels.  Athletes and coaches have since jumped on board and started giving it to their athletes, claiming it increases blood flow to your skeletal muscle and therefore improves cardiovascular performance.  This is incorrect for a number of reasons: firstly, the level of nitrates present in beetroots is far below that which is found in drugs designed to promote vasodilation, and is therefore unlikely to produce a significant effect.  Additionally, whilst it is true that nitric oxide does promote the dilation of blood vessels, at low doses, i.e. the levels found in beets, it only promotes dilation of the veinous system.  Whilst this is effective for lowering blood pressure, it will not aid increased blood flow to your skeletal muscle.  Finally, tolerance to nitrates build up very quickly, so even if there was a perceivable effect provided from beets, it wouldn’t last for more than a few days.  So beetroot is great to eat for its great taste, but it won’t help you ride faster.



Remember burning magnesium in high school chemistry?  That’s the same magnesium.

Another undoubtedly essential micronutrient for human survival, magnesium plays a critical role in the utilisation of ATP, our bodies’ major energy supply, among many other critical roles.  Again, this habit that some health food companies have of identifying a nutrient that is essential to our normal function, then marketing it to us as if we need to buy expensive supplements just to get by, rears its ugly head.  Yes, it is true that many people (approximately 60%) don’t get enough magnesium, but this is because magnesium comes from green, leafy vegetables, the main food people don’t like to eat.


Spinach is one of the most effective supplements you could add to your diet.

If you aren’t getting enough of these micronutrients, your training will suffer, but you can easily get enough of all the compounds listed here by eating a healthy diet with loads of green, leafy vegetables.  So if you want to improve, eat your veges, and train harder!


(1) Brisswalter, Jeanick, and Julien Louis. “Vitamin supplementation benefits in master athletes.” Sports Medicine 44.3 (2014): 311-318.

Image Credit

Vitamins – By Ragesoss – Own work, CC BY-SA 3.0,

Magnesium Flame – Hiroaki Nakamura

Categories: Nutrition

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