New Research!

By Robert A. Schinetsky

It’s no secret that we’re big fans of Leucine here at Advanced Molecular Labs. 

We’ve written quite a few articles detailing the benefits of the “anabolic trigger”, and we’ve also included 5 grams of Leucine in AML Post Workout to help dedicated fitness buffs build muscle & burn fat.

 The research surrounding the numerous benefits of leucine continues to pour in, and we’re here to provide the highlights.

But, before we get to the latest research on leucine, let’s briefly recap what makes it such a powerful amino acid.

What is Leucine and Why Should I Care?

Leucine is a branched chain amino acid (BCAA) that serves as the key anabolic trigger to protein synthesis. In fact, it is the most powerful stimulator of mTOR -- the pathway that drives cell growth and protein synthesis -- in the diet.[1]

You might also be interested to find out that testosterone acts via mTOR to promote muscle protein synthesis.[2] 

Research has also noted that the magnitude of increase in muscle protein synthesis following mealtime are dependent on leucine concentration.[3,4]

Even more intriguing is some research indicating that consuming a “sub optimal” amount of leucine-enriched protein (6.25 g protein with 5g leucine) at meal time can can be as effective as a high-protein meal (25 g) at stimulating increased MPS rates

This last point is especially noteworthy for older adults who struggle to consume enough protein, and these same individuals also battle anabolic resistance and sarcopenia.

Consuming enough leucine can help support muscle growth and prevent muscle loss.

Now that we’ve covered the basics on leucine, let’s now turn our attention to some of the most recent findings surrounding the “king” of amino acids.

New Leucine Research

Study #1: Leucine & Lean Muscle Mass

Much of the research focused on sarcopenia has been performed in individuals 65 years and older. However, it’s becoming increasingly understood that early prevention may be the best way to combat age-related muscle loss.

A recent study published in the journal Nutrients, gave 120 healthy community-dwelling adults either:

• leucine-enriched protein supplement [protein 20g (casein 50%+ whey 40%+ soy 10%, total leucine 3000 mg), vitamin D 800IU, calcium 300 mg, fat 1.1 g, carbohydrate 2.5 g], or
• isocaloric carbohydrate supplement

Individuals received these supplements twice a day for 12 weeks.[7]

At the end of the 12 weeks, researchers noted that leucine-enriched protein supplementation can have beneficial effects by preventing muscle loss.

It’s also worth mentioning that daily levels of physical activity did not change throughout this study in either group, since exercise can have an impact on muscle retention and growth.

Study #2: Leucine & Brown Fat

We’ve discussed brown adipose tissue (BAT) at length in previous articles, including TOP 10 THERMOGENIC & BAT ACTIVATORS.

If it’s been a while since you read those pieces and are in need of a quick refresher, BAT is a mitochondria-rich tissue that is primarily responsible for non-shivering thermogenesis.

Basically, brown fat burns calories at a higher rate than white fat, and helps maintain core temperature when exposed to cold weather. 

Animal studies indicate that chronic leucine supplementation may promote UCP-1 protein expression in BAT as well as decrease body weight and fat mass.[8]

Other research has found that acute supplementation of leucine may increase circulating insulin and glucose uptake in skeletal muscle.[9] 

A recent study published in April 2020 gives the first evidence that leucine potentiates glucose-mediated IBAT 18F-FDG uptake via β-adrenergic activation.[10]

The fact that leucine enhances glucose utilization may be particularly noteworthy for individuals in insulin-resistant states, which is a significant portion of the population and only continues to rise.

Researchers concluded that BAT activation may have important implications for promoting improved whole-body glucose metabolism -- something that’s very important when you consider how many individuals are overweight, obese, and/or diabetic.

Study #3 & 4: Leucine & Cytokines

Immune function is something that has been under heavy scrutiny in recent months, and there’s seemingly no end to the common person seeking ways to enhance their body’s resiliency and ability to combat infection. 

One of the major areas of focus regarding immune function centers are “the cytokine storm” -- a dangerous hyperimmune reaction to infection of the coronavirus in which the immune system overproduces inflammatory cytokines. 

This hyperproduction can damage the lungs and cause inflammation of the air sacs of the lung, which can inhibit oxygen delivery in the body, leading to pneumonia, respiratory failure and the requirement of a ventilator. 

Moreover, this cytokine storm can also lead to systemic inflammation, and thereby damage cells in the heart, liver, brain, kidneys, and intestines. Systemic inflammation is also higher in overweight and obese individuals.

A 2017 study published in the journal Scientific Literature Nutrition and Metabolism, found that free leucine supplementation, but not within a mixture of BCAAs, can influence serum cytokine pattern, which may promote a more anti-inflammatory pattern.[11] 

More specifically, IL-6 and IL-10 concentrations significantly decreased 60 minutes after supplementation with leucine. 

The reason that this finding is noteworthy is that IL-6 (interleukin-6) is a major inflammatory cytokine in COVID patients.

Interestingly, a steroid treatment commonly used for taming the cytokine storm is the glucocorticoid, dexamethasone.

However, glucocorticoids act as negative muscle protein regulators and contribute to whole-body catabolic state during stress.[12]

Specifically, glucocorticoids inhibit mTOR activity by evoking the activity of BCAT (Branched-chain amino acid aminotransferase)  -- a mitochondrial enzyme catalysing the first reaction in the breakdown of BCAA.

We also need to consider the fact that high Intensity exercise, itself, is a form of stress which raises cortisol levels. Cortisol is a catabolic hormone and can lead to muscle breakdown if left unchecked.

Research finds that leucine supplementation offsets glucocorticoid-induced inhibition on protein synthesis by evoking mTOR and suppressing AMPK pathway.

In other words, leucine can help stave off muscle protein breakdown and support muscle protein synthesis.

The Best Leucine Supplement

AML™ Post Workout contains 5 grams of pure leucine along with a full 5 grams of creatine monohydrate and 2.5 grams of betaine.

As we already mentioned, leucine stimulates protein synthesis, increases mTOR activity for several hours after training, combats protein breakdown, and supports muscle growth.

Creatine functions as a myostatin inhibitor and muscle support supplement, while betaine stimulates growth hormone (GH) and insulin-like growth factor-1 (IGF-1) secretion.

Combining all three into one powerful supplement supports muscle growth from multiple pathways, helping active individuals build more muscle and recover faster from intense workouts.

How to Take AML Post Workout

For best results we suggest taking one serving of AML Post Workout by itself (on an empty stomach) 15-30 minutes before a post-workout meal.

This allows for a greater spike in blood leucine levels than if you were to take AML Post Workout with a meal, since a mixed foods meal will slow absorption and leucine will have to contend with other nutrients for uptake. 

For the ultimate pre and post workout stack, we recommend using either AML PreWorkout or the New PreWorkout Xtreme before training and using AML Post Workout immediately following training.

Combining these two products supplies everything hard training athletes need to train harder and recover faster -- building more muscle, burning more fat, and getting the results they seek.

References

1. Atherton PJ, Smith K, Etheridge T, Rankin D, Rennie MJ. Amino Acids. 2010;38:1533–1539.
2. Basualto-Alarcón C, Jorquera G, Altamirano F, Jaimovich E, Estrada M. Testosterone signals through mTOR and androgen receptor to induce muscle hypertrophy. Med Sci Sports Exerc. 2013;45(9):1712-1720. doi:10.1249/MSS.0b013e31828cf5f3
3. Norton LE, Wilson GJ, Layman DK, Moulton CJ, Garlick PJ. Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutr Metab (Lond). 2012;9(1):67. Published 2012 Jul 20. doi:10.1186/1743-7075-9-67
4. Norton LE, Wilson GJ, Layman DK, Moulton CJ, Garlick PJ. Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutr Metab (Lond). 2012;9(1):67. Published 2012 Jul 20. doi:10.1186/1743-7075-9-67
5. Churchward-Venne TA, Burd NA, Mitchell CJ, et al. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012;590(11):2751-2765. doi:10.1113/jphysiol.2012.228833
6. Churchward-Venne TA, Breen L, Di Donato DM, et al. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. Am J Clin Nutr. 2014;99(2):276-286. doi:10.3945/ajcn.113.068775
7. Kang, Y.; Kim, N.; Choi, Y.J.; Lee, Y.; Yun, J.; Park, S.J.; Park, H.S.; Chung, Y.-S.; Park, Y.K. Leucine-Enriched Protein Supplementation Increases Lean Body Mass in Healthy Korean Adults Aged 50 Years and Older: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients 2020, 12, 1816.
8. Jiao, J.; Han, S.-F.; Zhang, W.; Xu, J.-Y.; Tong, X.; Yin, X.-B.; Yuan, L.-X.; Qin, L.-Q. Chronic leucine supplementation improves lipid metabolism in C57BL/6J mice fed with a high-fat/cholesterol diet. Food Nutr. Res.2016, 60, 31304.
9. Nishitani, S.; Matsumura, T.; Fujitani, S.; Sonaka, I.; Miura, Y.; Yagasaki, K. Leucine promotes glucose uptake in skeletal muscles of rats. Biochem. Biophys. Res. Commun. 2002, 299, 693–696.
10. Huska, B.; Niccoli, S.; Phenix, C.P.; Lees, S.J. Leucine Potentiates Glucose-mediated ¹⁸F-FDG Uptake in Brown Adipose Tissue via β-Adrenergic Activation. Biomedicines 2020, 8, 159.
11. Nicastro H, Carvalho M, Barquilha G, Ferreira LS. Leucine Supplementation: A Possible Anti- Inflammatory Strategy Evidences from a Pilot Study. SL Nutr Metab. 2017; 1(1):114.
12. Wang XJ, Yang X, Wang RX, et al. Leucine alleviates dexamethasone-induced suppression of muscle protein synthesis via synergy involvement of mTOR and AMPK pathways. Biosci Rep. 2016;36(3):e00346. Published 2016 Jun 17. doi:10.1042/BSR20160096