Dietary nitrates are most commonly found in vegetables such as green leafy veg, & beetroot. In the body, dietary nitrates can be converted to nitric oxide (NO), which dilates (widens) blood vessels, increases blood flow & lowers blood pressure.
Hypertension is a major risk for heart disease/cardiac events. The reduction in blood pressure from nitrates has been shown in both healthy people as well as hypertensive patients. Studies have demonstrated improvement of endothelial function, protection against ischaemia reperfusion injury & reduction in platelet aggregation too.
We know diets rich in fruits & vegetables are cardioprotective & dietary nitrate are likely to contribute to that. Compared to standard Western Diets, eating a Mediterranean diet can contain as much as 20 times the nitrate/nitrite content.
However it’s difficult to separate the nitrate in vegetables from the other nutrients which contribute to health. This includes fibre, vitamin C, polyphenols, folate, carotenoids, potassium & betaine. We can’t be sure how much the benefits are down to the nitrate content, or another compound, or a combination!
For performance, the increase in blood flow from nitrates means the muscles get more oxygen & glucose. Beetroot supplementation is often used in endurance sports, although results on performance are mixed. It seems to be more effective in trained or untrained individuals, rather than elite or professional athletes.
Along with reducing blood pressure, beetroot juice has been found to significantly reduce the O2 cost of low to moderate intensity (submaximal) exercise. The time to exhaustion during high intensity exercise was significantly increased from supplementation, as was performance in a time trial. It may be that elite athletes don’t get the same results as they already have higher basal plasma NO2 & NO3 concentrations from their endurance training. Another variable is if you eat a diet rich in nitrates your levels are already high so a supplement doesn’t give an extra benefit.
If you are taking part in an endurance event it may be worthwhile trialing in training to see any difference and if it helps.
References: Mac Nutrition Uni, Bondonno et al 2015, Bazzano et al 2003, Lundberg & Govoni 2004, Hu & Willett 2002, Bescos et al 2011, Bailey et al 2009 & 2010, Bryan & Hord 2010, Kapel et al 2015
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