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To be specific: initial studies included a "loading phase" (typically 5 d, but sometimes longer), leading subsequent investigations to just follow along. There are also animal data demonstrating changes in protein expression as a result of dietary nitrate supplementation, which, given the turnover rate of most proteins, would generally take at least a few days to occur (or at least be maximized). Together, these publications established the idea that you need to ingest nitrate for multiple days prior to competition.
If you actually pay attention to the data, however, especially in humans, there is (as I indicated before) very little, if any, evidence that the physiological effects of nitrate supplementation reflect anything other than just an acute effect:
Sadly, this is often the case in science, i.e., ideas become firmly established in peoples' minds before they really should, and it is only upon further study/reflection that things get properly sorted out. Indeed, I recently had to educate a reviewer of one of our articles about this very fact (i.e., they had bought in to the notion that there was a difference between acute and chronic supplementation).
A couple of more dietary nitrate-related "facts" that aren't really as solid as reading even the primary literature would lead you to believe:
1) The effects that are seen are the result of changes in nitric oxide availability specifically in type II, or fast-twitch fibers.
This hypothesis is based on the fact that, at least in rodents, the nitric oxide system plays a much more important role in type II vs. type I fibers. Andy Jones has therefore done a couple of studies attempting to demonstrate that this is also true in humans (e.g., by comparing the benefits of nitrate ingestion in subjects pedaling very fast vs. very slowly). In humans, however, endogenous nitric oxide production/action is just as high in slow-twitch and fast-twitch fibers, such that you wouldn't necessarily expect a fiber type-specific effect. Furthermore, when we analyzed data from subjects who functionally differed widely in muscle contractile properties, we did not see any correlation between an individual's apparent fiber type and the extent to which they benefited from nitrate supplementation:
2) Highly-trained subjects do not benefit from dietary nitrate supplementation.
It is true that highly-trained endurance athletes seem to benefit less, if at all, from nitrate supplementation, at least when it comes to the effects on endurance exercise. This could be due to frequent activation of the endogenous nitric oxide synthase system, leading to accumulation of nitrite and nitrate (NO -> NO2- -> NO3-). However, it doesn't seem to be true with respect to the effects of nitrate supplmentation on muscle contractile properties:
I discuss these issues in greater detail in this recent review:
Take two shots of Beet It and go from crappy 3k'er to less crappy 3k'er?
* mix beet supplement with baking soda or no benefit to do both?
Same questions...Based on the chart I'm trying to figure out what the best solution is. I'm leaning towards just doubling up on the Beet It shots.
The good news is that that means a more rapid onset of action, as shown in a recent study from Jones' lab.
The bad news is that the effects also dissipate more rapidly, as shown in the same study.
I will leave it to astute readers to figure out what the IU tech transfer office is working on. ;)
2019 Races: USAT State of CT Age Group Championship Sat June 15th (Oly/Du/Sprint) Wed eve July 10th, Sprint Tri Sat July 20th Hopkins Vineyard Tri at Lake Waramaug http://www.HopkinsVineyardTri.com
Beet It now sells a nitrate-free placebo to researchers such as myself, making it possible to do studies of nitrate per se, with BRJ just as the vehicle.*
Before it became available about 10 y ago, investigators were forced to use other juices (e.g., black currant juice) as the comparator. Unfortunately, this leaves unanswered the question of what substance or substances in BRJ is responsible for any effect that are observed.
*There are actually several studies suggestive of some interaction between nitrate and other compounds in BRJ, but they aren't very definitive.
Studies that have used only one have had rather mixed results; three doesn't seem to be any better than two (on average).
Funny that beetelite states right on the box: "Do not exceed more than one serving (10g) in 24 hours."
I generally grow a Detroit dark red variety as it seems the most common seed at the store, but there are others ruby queen, chiogga, golden varieties, etc
Wruss, J., Waldenburger, G., Huemer, S., Uygun, P., Lanzerstorfer, P., MÃ¼ller, U., HÃ¶glinger, O., Weghuber, J. (2015). Composition characteristics of commercial beetroot products and beetroot juice prepared from seven beetroot varieties grown in Upper Austria. J Food Comp Anal 42: 46-55.
grew the following varieties of beets all on the same 12 m^2 plot of land, then harvested them and analyzed their composition:
Agyptische, Plattrunde, Bolivar, Forono, Mona Lisa, Moronia, Redval and Robuschka. Nitrate contents in ug/mL were (in order) 1637 +/- 565, 914 +/- 422, 1730 +/- 526, 4626 +/- 658, 1358 +/- 742, 2963 +/- 279, and 564 +/- 129.
Unfortunately, I have no clue as to how these varieties might align with names that you might find in other countries.
ETA: Looking on Burpee Seeds just now, I see that they alone sell 16 different varieties...it is therefore perhaps unsurprising that beet juice from various sources varies markedly in nitrate content.
Looks like Lakewood do a concentrate now. Says that ~370ml bottle make ~1.4litres so just ordered to try that out: https://www.amazon.ca/gp/product/B075V37LF5/
If 1.4l of reconstituted beet juice has the same amount of nitrates as their normal beet juice (~18mmol / 500ml), you could get the same dosage as a "beet it sport pro-elite" (~6mmol / 70ml) in ~35ml of concentrate (36% of 125ml normal juice)
Cost wise beet it costs $73.60 CAD delivered for 15shots of 70ml (1.05l).
Lakewood beet concentrate, 2 bottles cost $36.40 CAD delivered for 21shots of 35ml (740ml).
So lots cheaper, and I won't feel bad experimenting with dosages and timings as much.
2018 Races: UBC Tri - 1st | IM Texas - 199th | IM Canada - 15th & KQ | Superleague Penticton - 4th | IM World Champs - 391st