Nitrates

Unfortunately, the nitrate concentration can differ between samples [2-3], making it impossible to know exactly how much nitrate you consume through vegetables (assuming you are not testing everything you eat in a lab!).

Mean concentration values that were found [2-3]:

  • Chinese Chive – 5150mg/kg
  • Spinach – 4259mg/kg & 2508mg/kg
  • Dill – 2936mg/kg
  • Lettuce – 2167mg/kg
  • Radish – 1878mg/kg
  • Chinese cabbage – 1740mg/kg
  • Beetroot – 1446mg/kg

Why should we care?

  • An old study by Lansley et al. (1986) showed that 6 days’ supplementation of 6.2 mmol nitrates increased the time to exhaustion during severe-intensity running by 15 % and reduced blood oxygenation compared to placebo [4]
  • Newer study by Wylie et al. (2013) showed that 490ml of beetroot juice, containing a total of 28.7 mmol nitrates, improved performance by 4.2 % during a running test and increased resting plasma nitrite concentrations by 400 % compared to placebo [5]
  • Fulford et al. (2013) showed that 15 days’ supplementation of 500ml of beetroot juice did not increase power output during a repeated isometric maximum voluntary contraction protocol compared to placebo [6]

It is pretty obvious that nitrate supplementation could be beneficial for many team sports (ex. football & rugby) as well as individual sports (ex. cycling, running & weight training).

Even though nitrate supplementation failed to increase power output I would still argue that nitrate can be beneficial for weightlifters as nitrate supplementation could increase weightlifters total training volume which could over time lead to better strength gains [7].

Nitrate supplementation or beetroots?

Flueck et al. (2015) had 12 healthy well-trained men either consumed nitrate-rich beetroot juice (BR), sodium nitrate (NIT) or placebo (PLC). The nitrate dosage was consumed 3 hours prior to exercise and they tested 3, 6 and 12 mmol nitrate supplementation. The exercise protocol consisted of 5 min cycling at moderate intensity and further 8 min at severe intensity. [8]

In the figure below you can see the different oxygen consumption at severe intensity exercise for BR-, NIT- or PLC supplementation.

he Wilcoxon test only showed significant difference between 6 mmol BR and NIT (p=0.003) when looking at oxygen consumption. 12 mmol BR significantly decreased systolic blood pressure whereas 12 mmol NIT did not reach significant differences.

The conclusion from Flueck et al (2015) was that Beets might be more beneficial at reducing VO2 and blood pressure compared to NIT.

Practical recommendations:

If you prepare your own pre-workout meal and are looking for a minor boost in performance, be sure to consume your vegetables! This shouldn’t really be a revalation – no matter what your goal it’s still important to eat a wide range of colourful vegetables!

Reading material, other benefits of consuming vegetables and fruits: https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vegetables-and-fruits/

Dosages

Lansley et al. (1986) and Flueck et al. (2015) showed that 6 mmol nitrate was sufficient to improve performance which is equivalent to ≈370mg nitrate. Examine.com state that 6.4-12.8mg/kg is the optimal dosage for nitrate supplementation [4, 8-9].

The table below shows you what amount of beetroots and spinach you would need to consume in your pre workout meal in order to meet the optimal dosage. I have also added two columns where I have calculated a 15 % safety margin due to the differences in nitrate concentrations.

If you want to consume any of the other sources I mentioned in the beginning you could just look at the mean concentration values and estimate what amount you need.

I always try to get around 375-400g of a nitrate containing vegetable in my pre-workout meal (weighing 75kg). 8 times out of 10 this is beetroot, as it tastes amazing and is easy to consume in bulk, but if I need to save more calories until later, I tend to change X to radishes or a mix of radishes, spinach, lettuce and Chinese cabbage.

If this seems like an insane amount of food, consider blending into smoothies or vegetable juices.

Tag me the next time when you get your nitrates in pre-workout at @ViktorBTN on Instagram and feel free to message me (through Facebook) for subjects that you want me to simplify, explain or to separate fact from fiction.

 

References

  1. Nabrzyski M & Gajewska R (1994). [The content of nitrates and nitrites in fruits, vegetables and other foodstuffs]
  2. Chung SY, Kim JS, Kim M, Hong MK, Lee JO, Kim CM & Song IS. (2003). Survey of nitrate and nitrite contents of vegetables grown in Korea
  3. Tamme T, Reinik M, Roasto M, Juhkam K, Tenno T & Kiis A (2006). Nitrates and nitrites in vegetables and vegetable-based products and their intakes by the Estonian population
  4. Lansley KE, Winyard PG, Fulford J, Vanhatalo A, Bailey SJ, Blackwell JR, DiMenna FJ, Gilchrist M, Benjamin N, Jones AM (1986). Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study
  5. Wylie LJ, Mohr M, Krustrup P, Jackman SR, Ermιdis G, Kelly J, Black MI, Bailey SJ, Vanhatalo A, Jones AM (2013). Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance
  6. Fulford J, Winyard PG, Vanhatalo A, Bailey SJ, Blackwell JR, Jones AM (2013). Influence of dietary nitrate supplementation on human skeletal muscle metabolism and force production during maximum voluntary contractions
  7. Strength & Conditioning Research (2016). Strength. https://www.strengthandconditioningresearch.com/strength/ [2016-06-20]
  8. Flueck JL, Bogdanova A, Mettler S and Perret C (2015). Is beetroot juice more effective than sodium nitrate? - The effects of equimolar nitrate dosages of nitrate-rich beetroot juice and sodium nitrate on oxygen consumption during exercise
  9. Examine (2016). Nitrate. http://examine.com/supplements/nitrate/ [2016-06-20]

Blog originally by Viktor Ström