|If you want other to see your pump, you got to be ripped. If not, why care about reductions in BMR?|
The bad thing: Arginine didn't work. The good thing: This means it didn't decrease your BMR, either
Against that background it's quite astonishing that arginine and citrulline based pre-workout products have dominated the top-seller lists of the big supplement vendors for decades. A fact that's probably partly due to other potential benefits of these amino acids, of which one - you as a SuppVersity reader know that - could be fat loss | learn more about the potential fat loss effects.
On a side note: I am pretty sure the fact that the other potential benefit is an increase in sexual stamina didn't hamper the sales either (Neuzillet, 2013; Hotta. 2014 ;-)With more and more people openly declaring that they would no longer waste money on "good tasting, but expensive and disfunctional products", they industry was yet pressed to develop alternatives. Luckily, our body has two options it can chose from, when producing nitric oxide.
Fortunately, the industry has developed better alternatives...?
You know option #1, the arginine ➲ nitric oxide pathway, and - with all the hype and hyperbole that surrounded the introduction of the first nitrate supplements - I am pretty sure, you know the other one as well, the nitrate-nitrite ➲ nitric oxide pathway
|Figure 1: The Arginine- and the Nitrate-Nitrite - NO pathway are the yin and yan of nitric oxide production (Lundberg. 2008).|
With the "yan", i.e. the nitrate-nitrite ➲ nitric oxide pathway being a relatively "new kid on the NO block", that recycles (=reduces) inorganic anions nitrate and nitrite to form bioactive NO in blood and tissues during physiological hypoxia.
It goes without saying that there is a bottle neck to this process as well, but the rate limiting availablility of oxygen which hampers the argine-based NO generation by NOS becomes limited as oxygen levels fall is actually a signal for the nitrate–nitrite ➲ nitric oxide to really kick in.
There is more yin and yan, here
If you take a closer look at the results of a study in the America Journal of Clinical Nutrition (Figure 2), you will yet have to realize that there is "more yin and yan", here than you'd probably hope for. According to the data scientists from the venerable Karolinska Institutet in Stockholm, Sweden, present in their paper, "[d]ietary inorganic nitrate reduces the RMR." (Larsen. 2014)
|Figure 2: VO2 consumption (marker of fatty acid oxidation) and basal metabolic rate (BMR) relative to means (left), thyroid hormone (T3, T4) levels after 3-d dietary intervention with sodium nitrate (Larsen. 2014)|
Interestingly, these effects were not - as you may have been speculated - brought about by changes in thyroid hormone status. And the subjects insulin sensitivity, glucose uptake, plasma concentration of isoprostanes, as well as their total antioxidant capacity were unaffected, as well.
- Bailey, Stephen J., et al. "Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans." Journal of Applied Physiology 107.4 (2009): 1144-1155.
- Hotta, Yuji, et al. "Oral l‐citrulline supplementation improves erectile function and penile structure in castrated rats." International Journal of Urology (2014).
- Larsen, Filip J., et al. "Dietary inorganic nitrate improves mitochondrial efficiency in humans." Cell metabolism 13.2 (2011): 149-159.
- Lundberg, Jon O., Eddie Weitzberg, and Mark T. Gladwin. "The nitrate–nitrite–nitric oxide pathway in physiology and therapeutics." Nature Reviews Drug Discovery 7.2 (2008): 156-167.
- Neuzillet, Y., et al. "A randomized, double‐blind, crossover, placebo‐controlled comparative clinical trial of arginine aspartate plus adenosine monophosphate for the intermittent treatment of male erectile dysfunction." Andrology 1.2 (2013): 223-228.