Friday, January 24, 2014

The Beat Your Personal Bests W/ Beets 101: How Much? 8.4 mmol Nitrate ~400-1300g Beets! When? 2.5h Pre Workout!

There are two things you have to keep in mind, when you want to reap the benefits: Timing and dosage. With the currently available nitrate-based / -containing supplements, and both were probably off for the average customer.
It has gotten quiet around nitrate supplements. Irrespective of a handful of interesting studies that were published in the past months (Hoon. 2013; Thompson. 2013), the negative results got more attention among the disappointed consumers of one of the profoundly underdosed nitrate supplements that have suffocated the initial enthusiasm on part of the average and extraordinary gym rat.

The use of the natural alternative, i.e. beet root juice, on the other hand, is complicated, because there is little information on how much nitrate you need and how much of it can be found in the average beet from the supermarket.
Nitrates for your heart: I know ergogenics are sexy, but how sexy is an increase in performance for someone who suffers from regular age- or self-induced lifestyle-related increases in large elastic artery stiffness and endothelial dysfunction? Against that background it's good to know that a group of researchers from the University of Colorado Boulder conclude in their review of the literature that "inorganic nitrite, as well as dietary nitrate, supplementation represents a promising therapy for treatment of arterial aging and prevention of age-associated CVD in humans." (Sindler. 2014)
Luckily Lee J. Wiley et al. must have realized that as well and set out to characterize the plasma NO3 and NO2 pharmacokinetics and the changes in BP after ingestion of three different quantities of NO3-rich beet root juices, as well as the corresponding dose-response relationship between beet root juice and NO3 intake and the physiological responses to exercise. To this ends, the researchers administered different amounts of a beet root concentrate, i.e.4.2, 8.4, and 16.8 mmol from 70, 140, and 280 ml of Beet It, and measure the plasma NO3 and NO2 response, and the blood pressure (BP) of their 10 healthy, recreationally active volunteers (23 yr, height 1.79m, weight 79kg) over a 24h period.
Figure 1: Average plasma NO3 and NO2 levels in healthy male volunteers after the consumption of different amounts of beet root juice concentrate (Wiley. 2014)
As you can see in Figure 1, the effects were dose-dependent and, with respect to the change (not the absolute values) in peak and average NO3 & NO2 levels, almost linear. A similar linearity was not observed for the systolic blood pressure levels which dropped (luckily) not significantly more in response to the ingestion of 16.8 vs. 8.4mmol of nitrate.
Figure 2: The profound drop in systolic BP could be a problem if your BP is already low ➲ dizziness and -worst case- blackout!
"[...S]ignificant main effects by dose and time and an interaction effect on systolic BP (all p < 0.05). [...] The peak reduction in systolic BP occurred 4 h postadministration of 4.2 (5  mmHg), 8.4 (10 mmHg), and 16.8 mmol NO3 (9 mmHg), respectively, relative to baseline (all p < 0.05). Systolic BP was reduced relative to baseline, CON, and 4.2 mmol NO3, at 2, 4, and 8 h postadministration of 8.4 mmol and 16.8 mmol NO 3 (all p < 0.05). There were no differences in systolic BP between 8.4 and 16.8 mmol NO 3 at any time point ( p < 0.05)." (Wiley. 2014)
In that it's certainly remarkable that these effects lasted for 24h, so that the systolic blood pressure was still significantly lower (by 5 mmHg) than at baseline when the scientists took the last reading.
Low blood pressure warning: For the average Westerner it certainly wouldn't be a problem if his blood pressure dropped by 10mmHg, but for a trained athlete who may already have a relatively low systolic BP, the high 16.8mmol (=280ml Beet It) could be straw that breaks the camels neck, i.e. make you feel as if you would black out (see Figure 2).
A similar effect, albeit not dose-dependent effect was observed for the diastolic blood pressure, which dropped significantly, relative to baseline and CON (all p < 0.05). As the researchers point out, the peak reduction in diastolic BP from baseline occurred at 4 h postadministration of 8.4 mmol NO3 (3 3 mmHg) and 2 h postadministration of 16.8 mmol NO3 (4 4 mmHg; both p< 0.05) relative to baseline (both p < 0.05) and returned to near-baseline values by 24 h (p < 0.05).

"What about the really important stuff?"

Oh yes, I almost forgot the effects the scientists observed, when the subjects consumed the beetroot juice 2.5h before a "moderate- and severe-intensity exercise" in the form of a "step" exercise test (20W ➲ 93W ➲ 258W) on a cycle ergometer.
Figure 2: Increase in time to exhaustion (="task failure) during incremental exercise test and average nitrate content (g/100g; based on Wiley. 2013) of beets depending on fertilizer use; the values on top indicate the amount of beets you would have to consume to get to the 8.4mmol nitrate threshold (based on Lee. 1971)
As you can see in Figure 2, these effects, here an increase in the time to exhaustion / "task failure" were not - as the more helps more logic would suggest - most pronounced after the ingestion of the maximal dosage of 16.8mmol of nitrate.

That's good for you, because as you can see on the right hand side of Figure 2, you do already have to consume more 1.3kg of unfertilized beet roots to get up to the medium and most effective dosage of 8.2mmol of nitrate.
Juicin' allowed: You know that I strongly advice against turning your fruits and veggies into an indistinguishable mush, but for beet roots it's probably necessary. Otherwise the nitrate peak will either be postponed or non- existent and the effects the researchers ob- served in the study at hand will be blunted or won't occur at all.
Bottom line: The study at hand confirms that the assumption that more helps more rarely applies, when the thing you could take / have / ingest more of are dietary supplements. Rather than taking more, you should thus make sure to get the timing right - 2.5h before the workout(!), that's when you want to take your nitrate supplements or drink your beet root juice.

In this context, it's worth mentioning that timing, as well as the speed of absorption (see info box to the right) are probably less important, if you are looking for the recently confirmed beneficial effects of nitrite, as well as dietary nitrate, on arterial aging and prevention of age-associated CVD in humans (Sindler. 2014), I discussed in the info-box "Nitrates for your heart".
  • Hoon, Matthew W., et al. "The Effect of Nitrate Supplementation on Exercise Performance in Healthy Individuals: A Systematic Review and Meta-Analysis." International journal of sport nutrition and exercise metabolism (2013).
  • Lee, C. Y., et al. "Nitrate and nitrite nitrogen in fresh, stored and processed table beets and spinach from different levels of field nitrogen fertilisation." Journal of the Science of Food and Agriculture 22.2 (1971): 90-92.
  • Sindler, Amy L., et al. "Inorganic Nitrite Supplementation for Healthy Arterial Aging." Journal of applied physiology (Bethesda, Md.: 1985) (2014).
  • Thompson, Kevin G., et al. "Influence of dietary nitrate supplementation on physiological and cognitive responses to incremental cycle exercise." Respiratory physiology & neurobiology (2013).