|Adelfo's latest progress pics speak for themselves. Maybe that consoles you for the missing update!?|
SuppVersity Science Round-Up Sneak Peak
Apropos sleep, I guess sleep is going to be one of the topics Carl and I are going to talk about on today's SuppVersity Science Round-Up (check out all previous installments and the respective Seconds, here), other topics I've got on my list here, are the Aspartame causes cancer study that resurfaced as of late on the pertinent "science websites" as if it had been released yesterday, and a couple of other news, e.g.
- The thrifty phenotype - Is it an effect of "healthy calorie restriction" during gestation?
- Fish protein & glucose metabolism - More evidence that a little can go a long way
- Eat more fruits & vegetables! - Why "more" is not specific enough
- Vitamin D - Convincing evidence that the obesity connection is a one-way street
- BPA and prostate cancer - Changes in aromatase and 5α-reductase increase malignancy
- Night shift & breast cancer - Meta analysis finds 30%+ increased risk
Chronic leucine supplementation + hypercaloric diet = ???
The subheading actually summarizes pretty well, what the scientists from the School of Public Health at the Huazhong University of Science and Technology, the Department of Nutrition at the University of North Carolina at Chapel Hill and one colleague from the Hubei University of Medicine in the People's Republic of China wanted to find out, when they bought a group of male Sprague-Dawley rats, and kept them in eight groups of 10 animals for 24 weeks on one of the following dietary regimen
|normal chow diet (3.78 kcal/g)||hypercaloric "high fat"(54%) diet (5.20 kcal/g)|
|+ 0%, 1.5%, 3.0% or 4.5% leucine||+ 0%, 1.5%, 3.0% or 4.5% leucine|
|Figure 1: Body weight development (remember the food intake was identical) and perirenal fat depot weight at the end of the study (Lee. 2013)|
[T]he perirenal white adipose tissue was −1.20% of the total body weight in animals on ND [nromal diet]. HFD alone increased the perirenal fat to 1.62% (p<0.05). Chronic supplementation of leucine (1.5 and 3.0%) increased the percentage of the perirenal white adipose tissue to 2.01–2.03% in animals on HFD (p<0.05). [...] These results show that chronic supplementation of leucine increases the ratio of white fat over total body weight in rats on HFD." (Li. 2013)Interestingly, this increase in adiposity went hand in hand with a decrease in the expression of TNF-alpha and various inflammatory cytokines in the adipose tissue of the rodents. The picture of leucine that emerges here is therefore one of a "healthy growth factor". unfortunately one that obviously does not make a difference between muscle and fat tissue.
Leucine as a non-selective growth promoter and insulin sensitizer
Whether the decrease in inflammatory cytokines is the chicken or the egg here cannot be said for sure. What is pretty certain though is that the combination of decreased inflammation → increased adipose tissue insulin sensitivity → increase energy uptake by the fat tissue may lead to a healthier, but certainly not smaller adipose organ and does thus go against what the usual muscle head would be looking for, when he or she buys a product that claims to provide lean mass gains.
|Figure 3: HOMA-IR and Area Under the Curve (AUC) of the glucose response in a glucose challenge (Lee. 2013)|
|Figure 3: Plasma insulin response to the ingestion of 0.7g/kg CHO, 0.7g/kg CHO + 0.3g/kg WPH, and the former with additional 0.1g/kg leucine in type II diabetics and healthy controls (Manders. 2006)|
Bottom line: You could in fact argue that leucine works much like the diabetes drug rosiglitazone. While the underlying mechanism it totally different, the outcome is very similar. Both increase the insulin sensitivity by reducing adipose tissue inflammation and allowing for greater energy storage in the fat tissue. Good or bad thing? Well, I guess for the majority of SuppVersity readers of whom I hope that they are not type II diabetics an only battling with one or another unaesthetic, but totally healthy pound of body fat, this is bad news.
|Even if it was not for the non-specific and potentially obesogenic insulin sensitizing effects of leucine, the increased protein anabolic response to whey hydrosolate compared to free form amino acids is another thing that speaks against the use of leucine or other free-form amino acis in isolation. After all, you would be missing out on the anabolic effects of the peptides in whole proteins (read more).|
If you also take into consideration the latest SuppVersity post on the non-insulin dependent increase in skeletal-muscle glucose uptake from isoleucine, the #3 in the original branch-chain amino acid concert (leucine, valine, isoleucine; read more), you better keep away from bulk supplies of l-leucine and "superior high leucine BCAA powders" and stick to the tried and proven.
- Balage M, Dardevet D. Long-term effects of leucine supplementation on body composition. Curr Opin Clin Nutr Metab Care. 2010 May;13(3):265-70.
- Koopman R, Verdijk LB, Beelen M, Gorselink M, Kruseman AN, Wagenmakers AJ, Kuipers H, van Loon LJ. Co-ingestion of leucine with protein does not further augment post-exercise muscle protein synthesis rates in elderly men. Br J Nutr. 2008 Mar;99(3):571-80. Epub 2007 Aug 13.
- Li X, Wang X, Liu R, Ma Y, Guo H, Hao L, Yao P, Liu L, Sun X, He K, Cao W, Yang X. Chronic leucine supplementation increases body weight and insulin sensitivity in rats on high-fat diet likely by promoting insulin signaling in insulin-target tissues. Mol Nutr Food Res. 2013 Feb 13.
- Manders RJ, Koopman R, Sluijsmans WE, van den Berg R, Verbeek K, Saris WH, Wagenmakers AJ, van Loon LJ. Co-ingestion of a protein hydrolysate with or without additional leucine effectively reduces postprandial blood glucose excursions in Type 2 diabetic men. J Nutr. 2006 May;136(5):1294-9.