|Image 1: I wonder whether the silk worms, themselves, aren't a "highly anabolic" source of dietary protein as well... for the time being, BPI (and I assume a handful of soon to follow copy cats) rely on their produce, though.|
A silky ergogenic from the domesticated silk moth?!
In fact, my interest in the silk proteins, which are the major (as far as the hitherto available information is concerned, even the "only") ingredient of BPI's new product, dates back to 2010, when Shin et al. published the results of a rodent study, which found that supplementation with 500mg/kg (HED ~40mg/kg) silk amino acids for 42 days increased the maximal (loaded) swimming time in mice by more than +100% while concomittantly increasing the gain in total lean body mass by ~15% over the unsupplemented, yet exercised control (Shin. 2010).
|Figure 1: Blood glucose, liver glycogen, muscle glycogen, plasma protein, corticosteroid and testosterone levels in mice after 42days of 30min daily swimming exercise; data expressed relative to sedentary control (data calculated based on Shin. 2010)|
|Figure 2: Amino acid composition of the silk protein hydrosolate from Worldway Co., Ltd. (Jeoneui, Korea) that was used in the exercise study (data adapted from Shin. 2010)|
So, how does that stuff work? I mean, it does work, right?
A recently published study by scientists from the Korea University in Seoul does yet shed some light at least onto the not immediately ergogenic effects of silk protein hydrosolates. In an in-vitro experiment with 3T3-L1 fibroblasts (stem cells that would usually form connective tissue), Hyun-Sun Lee, Hyun Jung Lee, Hyung Joo Suh were able to show that the fundamental physiological processes that are responsible for the improvements in glucose and lipid metabolism reported in previous studies (Gao. 2000; Hyun. 2004; Lee. 2007) are in fact attributable to two of our old acquaintances: Increases in GLUT-4, the glucose transporter on the cell surface of eg. muscle tissue, and leptin, the adipokine that tells your body that there is more than enough fat to burn (Lee. 2011).
|Figure 3: Glucose uptake in fibroblasts incubated with different amounts of silk protein with and without insulin and insulin and piogliazone controls; data expressed relative to untreated control (data adapted from Lee. 2011)|
|Figure 4: Relative mRNA expression of selected transcription factors in adipogenesis pathway after incubation of fibroblasts with either 1mg/mL silk protein hydrosolate or 50nM pioglitazone (data adapted from Lee. 2011)|
BPI is right, I have been waiting for this, but I am still waiting for more studies, as well ;-)
|Image 2: Even if it turns out to be another supplement non-starter, the BLOX box looks nice, doesn't it?|
So, even if the currently available research does suggest that "silk proteins" hold some promise, these products are fundamentally different from your usual amino acid supplements, because their biological activity is a function of both their amino acid composition, as well as the structural arrangement of those aminos within individual proteins and peptides. The source, the way the product is processed and God knows what else will thusly decide whether BPI's BLOX will become a valid addition (I am sure it won't replace whey proteins) to the established supplemental protein sources, or whether it will end up in one of those niches of the supplement stores right next to pea and other exotic protein sources.