Written by Victor R. Prisk, M.D.
11 August 2018

17NN310-Leuc

The Super Supplement

Leucine - #1 Muscle Activator

 

 

Muscular Development is all about its namesake— the development of muscle. Our bodies build muscle in response to hours of pounding in the gym and attention to recovery outside the gym. Training literally beats us down. Training puts our bodies in a catabolic state, breaking down glycogen, muscle and fat. With the right behaviors in the kitchen and the shaker cup, we can reverse this destructive process and grow from our efforts.

 

Nature inherently wants to conserve energy, and building muscle takes lots of energy. Muscle is heavy, and metabolically active. If there’s no fuel available, nature says we can’t afford to build muscle. Our bodies have to be able to sense whether there is enough fuel in our environment to build muscle.

 

It was once thought that insulin was the driving force behind muscle growth. If sugar calories were available, muscle could grow, right? Boost insulin and build muscle, right? Wrong! The existence of plenty of sugar (glucose) in our system only tells the body that we don’t need to break down muscle for energy. Thus, insulin’s main role is to store those nutrients and avoid breakdown of what was stored.

 

Insulin encourages the body to store glucose in muscle, liver and fat. It clears toxic sugar out of our blood. Yes, sugar is toxic. Sugar caramelizes our insides in a reaction with proteins that makes them foreign to our immune system. The subsequent inflammation from sugar leads to further tissue damage, insulin resistance and an inability to repair muscles after exercise.1 Sugar is KRYPTONITE! It makes us weak!

 

In fact, it only makes sense that nature would have a non-insulin-dependent way of differentiating whether or not there are nutrients available to build muscle. Since our bodies can make glucose from particular amino acids and fats, glucose isn’t a great way to sense whether nutrients are available in our environment in order to grow. In other words, we need a better signal, a “key” if you will, to build muscle other than glucose, because our bodies already auto-regulate blood glucose to feed the brain.

 

The Anti-Kyrptonite That Builds Muscle

We need the “anti-kryptonite.” It would make sense that the nutrient signal from our food would come in the form of an essential nutrient that our bodies can’t make and can’t become glucose. There are essential amino acids, essential fats, but no essential carbohydrates. Since the essential fats play a structural role and combine with a glycerol backbone that can be converted into glucose, this leaves the essential amino acids as a potential “key” to turn on our nutrient sensor.

 

In particular, the essential amino acids that our body can’t convert to glucose (i.e., non-gluconeogenic or purely ketogenic), lysine and leucine, make the most sense as a nutrient to turn on muscle. However, lysine can be converted to carnitine for fat shuttling, and its uptake is easily inhibited by leucine; thus, leucine wins! Leucine is the anti-kyrptonite!1 It can’t become glucose, it stimulates insulin release and it builds muscle as metabolic currency!

 

Science supports that, there’s a threshold in our diets that must be met in order to turn on muscle protein synthesis. One study demonstrated that distributing protein evenly throughout meals in the day was more effective than the typical “skewed” American diet.2 Most Americans eat very little protein at breakfast, a little more at lunch and a lot more at dinner. When scientists put equal amounts of protein in each meal with the same daily total as a skewed diet, the equally partitioned meals resulted in better muscle protein synthesis.

 

Further, when balanced protein is fed to those dieting with four meals per day, they maintain muscle better than when they follow a skewed protein pattern.3 This probably isn’t news to you, as most bodybuilders understand the importance of preparing high-protein meals evenly spaced throughout the day when prepping for a show. Just like any other “stimulus,” whether lifting for a body part or eating a meal, the system needs some downtime to restart growth.4 It is presumed by this research on skewed diets that a threshold for turning on muscle protein synthesis wasn’t being met by the lower-protein meals (breakfast and lunch).

 

Science has suggested that the threshold for turning on muscle protein synthesis is met by the leucine content of a protein. Our bodies sense the leucine content of our meals through complex molecular mechanisms. Simply, leucine acts as the “key” to turn on muscle protein synthesis through direct and indirect activation of the mTOR pathway.1 Moreover, it does this in a manner that doesn’t depend on the presence of insulin.5 Thus, the leucine content of a meal could affect a meal’s ability to build muscle after training.

 

Despite the confusion created by the Recommended Dietary Allowance (RDA) for protein requirements of 0.8 grams per kilogram of bodyweight per day, sports science shows that this is highly inadequate for strength-training athletes. Furthermore, the RDA doesn’t say “high-quality proteins.” All proteins are not created equal in their ability to support metabolism and build muscle. Studies show that it takes 30 percent more soy protein to have the same effect on muscle protein synthesis as whey protein.6 It just so happens that whey protein has 30 percent more leucine, gram for gram, than soy protein.

 

Our Bodies Respond With Muscle Growth

Regardless of all this science, we, as humans, are definitely made to respond to leucine with growth! Whey is the protein richest in leucine. Whey and casein make up the milk proteins. Cow’s milk contains 80 percent casein and 20 percent whey. However, human milk contains 60 percent whey and 40 percent casein. Mother’s milk contains nearly 10 percent leucine, similar to whey protein concentrates. When we are growing our most, as infants, nature has decided that we need more leucine. If you want to grow, you need to focus on the leucine content of your meals.

 

Some feel that once leucine has reached a minimum threshold, often around ~2 grams in a meal, muscle protein synthesis is maximally turned on and extra leucine won’t have a greater effect. However, a study in relatively young, active-duty military personnel demonstrated that 3.5 grams of leucine mixed with essential amino acids was more effective in turning on muscle protein synthesis than 1.87 grams of leucine with the same amino acids.7 Besides, the older we get, the less sensitive we become to leucine’s signal to make muscle.8

 

One thing is for certain— you can’t just chew on leucine all day and expect to grow lots of muscle. Leucine is the key to turn on the car (so to speak), but you need fuel to keep it running, which also requires intermittent rest stops. Leucine acts as a switch to turn on muscle growth, but if the essential amino acids found in complete proteins aren’t available, there are no materials to build the muscle. When scientists put leucine in the drinking water of rats, despite the constant leucine stimulus, they failed to build more muscle. When there is a “de-synchronization” in the leucine stimulus and availability of essential amino acids, we fail to achieve the goal of turning on muscle growth.8

 

In addition, leucine may act as a signal to limit food intake by acting on mechanisms in the brain.9 Leucine says, “Quality food has been eaten, and we can stop eating now.” This is great if your goal is to lose weight and starve yourself, but if you stop eating without having eaten a good blend of essential aminos from food, your muscle won’t grow. The moral of the story is that leucine is nature’s way of knowing that high-quality protein has been eaten and we can build muscle. You shouldn’t take leucine supplements by themselves to build muscle.

 

My suggestion, as explained by my book Leucine Factor Diet and App (available at the App Store), is that you should shoot for optimizing the leucine content of the proteins you eat. All proteins have a different percentage of leucine. Shoot to optimize your muscle metabolism and insulin sensitivity with the anti-kryptonite effects of leucine.

 

 Dr. Victor Prisk is a board certified orthopaedic surgeon and IFBB professional bodybuilder in Pittsburgh, PA. Dr. Prisk is an active member of the GNC Medical Advisory Board and creator of the “G.A.I.N. Plan.” He is an NCAA All-American gymnast, champion swing dancer and NPC Welterweight National Champion.

 

References:

1. Prisk V. The Leucine Factor Diet, Ulysses Press 2015 (in Press).

2. Mamerow MM, et al. J Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. Nutr 2014 Jun;144(6):876-80.

3. Murphy CH, et al. Hypoenergetic diet-induced reductions in myofibrillar protein synthesis are restored with resistance training and balanced daily protein ingestion in older men. Am J Physiol Endocrinol Metab 2015 May 1;308(9):E734-43.

4. Atherton PJ, et al. Muscle full effect after oral protein: time dependent concordance and discordance between human muscle protein synthesis and mTORC1 signaling. Am J Clin Nutr 2010;92:1080-8.

5. Bennet WM, et al. Inability to stimulate skeletal muscle or whole body protein synthesis in type 1 (insulin-dependent) diabetic patients by insulin-plus-glucose during amino acid infusion: studies of incorporation and turnover of tracer L-[113C]leucine. Diabetologia 1990;33:43-51.

6. Norton LE, et al. Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutr Metab (Lond) 2012 Jul 20;9(1):67.

7. Pasiakos SM, et al. Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis. Am J Clin Nutr 2011 Sep;94(3):809-18.

8. Dardevet D, et al. Muscle wasting and resistance of muscle anabolism: the “anabolic threshold concept” for adapted nutritional strategies during sarcopenia. Scientific World Journal 2012;2012:269531.

9. Cota D, et al. Hypothalamic mTOR signaling regulates food intake. Science 2006;312:927-30.

 

Supplements Cause Lumps In Your Nuts!

By Victor R. Prisk, M.D.

 

The title of this sidebar is almost as ridiculous as the science to be discussed here. A recent “scientific” article has suggested that using muscle-building supplements can cause testicular cancer. These studies are almost as good as the studies saying that fish oil causes prostate cancer, or that chocolate is good for you.

 

There may be some mildly useful data in some of these studies to suggest a need for further research, but in no way are these studies powerful enough that they should make headlines. Unfortunately, the “lame-stream” media has latched on to the studies to create sensational headlines to catch your attention like the title of this sidebar.

 

The pseudo-scientists who suggested this correlation lumped together a survey of 30 different compounds that subjects used at least one time per week for four weeks. This sounds a lot like how a bodybuilder takes supplements … NOT! Sorry, I loved the ‘90s. It is suggested that because supplements are often tainted and unregulated, that this is perhaps the reason for the carcinogenesis.

 

Folks, there is a growing army against your supplements forming in Washington and the scientific community (Dr. Pieter Cohen, to name one). Contact your Congressman to protect your supplements. I am all for boosting manufacturing oversight and truth-in labeling standards for your safety, but there are those who seek to take down the entire industry. What then happens is they gain control of your supplements, and they become as expensive as Viagra at $20 per pill.

 

Reference:

Li N, et al. Muscle-building supplement use and increased risk of testicular germ cell cancer in men from Connecticut and Massachusetts. Br J Cancer 2015 Mar 31;112 Suppl:1247-50.

 

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