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Loving Leucine | Muscle & Body Magazine

I’ve talked about amino acids before in regards to their involvement in brain function due to concussions, but new research discussing the topic of muscle protein synthesis after resistance training based out of the American College of Sports Medicine shows that the amino acid leucine is “suggested to be a primary mechanism for increased muscle anabolism.” This, of course, is beneficial for optimal protein absorption and utilization.

Fast and Furious

The proteins we take in before or after a workout are usually categorized as “fast-acting” or “slow-acting.” Digestion speed determines the optimal time for intake, whether from a protein source like whey immediately postworkout, or casein right before bed. It’s long been believed that a fast-acting protein such as whey is ideal for postworkout consumption because this protein is rich in the amino acid leucine, causing a faster commencement of protein synthesis.

Speeding the process of protein synthesis is critical to a postworkout routine because the one-hour period after any sort of exercise, such as resistance training, is a crucial time for protein intake and absorption. The rich intake of leucine you receive when ingesting whey protein increases your chances for growth due to its effects on muscle anabolism (this is, of course, assuming you maintain a healthy diet and consistent exercise regimen).

The same research I mentioned earlier on protein synthesis by the American College of Sports Medicine states, “The best protein source for consumption soon after resistance exercise is the one that is quickly digested and able to promote a rapid increase in plasma leucine concentrations.” The research goes on to say that “slow- [digesting] protein produces an inferior response [compared] to a fast-[digesting] protein when consumed after resistance exercise.”

Leucine appears to be a key branched-chain amino acid that affects muscle growth. As I mentioned, milk subfractions like whey and casein are usually referred to when talking about fast- or slow-digesting proteins, but we now know that other forms of protein can act just as fast or slow. When trying to maintain a high-protein diet, look for foods rich in leucine. For example, “Liquid forms like soy milk or skim milk achieved peak [leucine] concentrations twice as quickly after ingestion than solid protein-rich foods like eggs, steak, or a protein bar, whereas skim milk achieved significantly fast peak leucine concentrations than all other foods.”

The Key Driver in BCAAS

How about taking leucine during exercise? This gives you the advantage of having a higher leucine concentration to avoid muscle breakdown during a workout, while also elevating leucine levels going into your postworkout consumption of fast-acting protein.

What about those who supplement their protein intake preworkout? Studies suggest that if you are going to consume your protein before a bout of resistance training, it does not matter whether or not it is a slow- or fast-acting protein so long as adequate leucine supplementation is added.

What products can you take to aid in leucine supplementation? A good branched-chain amino acid supplement should consist of valine, isoleucine and leucine—leucine being the key factor to increase muscle anabolism. GNC sells many great BCAA products. Some of the ones I found to be more successful were Modern BCAA by USPlabs, or Instantized BCAA 5000 Powder and Superior Amino 2222 Tabs by Optimum Nutrition.

There are many benefits of supplementing amino acids into your diet on top of protein. In fact, an amino acid like leucine could potentially benefit you faster than other protein sources. One reason for this is that amino acids are small enough to be readily absorbed by the body without prior digestion as opposed to a whole-food (solid) or powdered protein source. This is why they are ideal to take intraworkout—your body can use them as needed during the stress it endures while performing resistance training.

If you haven’t already considered adding leucine to your diet with a quality BCAA supplement, you may want to start. With scientific studies to back these statements up, you might be amazed at the benefits these small but easily absorbed compounds can produce. As always, talk to your doctor first to make sure you are healthy enough for resistance training.via Loving Leucine | Muscle & Body Magazine.