BCAAs: The Three Amigos of Amino Acids

Today's topics include BCAAs, my recent Leadville podcast appearance—and check out my new logo! Snazzy, right?

The Upshot, Upfront:

• Advocates say BCAAs help build muscle, fuel exercise, and delay fatigue.

• There’s science behind these claims, but there are also caveats.

• If you’re curious, it doesn’t hurt to give them a try.

Branched Chain Amino Acids, better known as BCAAs, have panacea status in the supplement world. They build muscle! They fuel workouts! They ward off fatigue! They’re a floor wax and a dessert topping!

But do they really do all those things? For the last two, no. That was just me dating myself with an old SNL reference. For the first three, yes, but maybe not as awesomely as we all hoped.

Leucine, isoleucine, and valine make up the BCAA trifecta. They’re three of the nine essential amino acids and they get their name from a spare “branch” on their molecular structure that has a few extra atoms hanging off the end. (If you were hoping for something cooler, I’m sorry.)

Each member of Team BCAA has its own strength. Leucine, widely considered the most important of the three, is particularly good at inducing protein synthesis (muscle building and repair). Valine also plays this role, although to a lesser degree. It is also believed to delay muscle fatigue during prolonged exercise. Isoleucine is good at stimulating glucose intake into muscle cells, thus helping to fuel them.

Do they fuel workouts?

Technically, yep. In a pinch, amino acids can convert to glucose in the liver through a cumbersome process called gluconeogenesis. BCAAs don’t require gluconeogenesis. Once in the bloodstream, they can b-line straight to muscles for use as fuel, sparing your glycogen. There’s research showing that pre-event BCAAs may help do this, but remember that when it comes to energy, carbs are queen. The benefit you might get from BCAAs is a drop in the bucket compared to proper carbohydrate usage, so don’t load up on BCAAs in lieu of sugar.

Do they build and repair muscle?

Yes, but with a caveat. Supplementing them on their own probably doesn’t do much, as this rather incendiary article in the Journal of International Sports Nutrition points out, “We conclude that the claim that consumption of dietary BCAAs stimulates muscle protein synthesis or produces an anabolic response in human subjects is unwarranted.”

However, the article qualifies this smack down: “BCAAs may enhance the anabolic effect of a protein meal. For example, the addition of 5 g of BCAAs to a beverage containing 6.25 g whey protein increased muscle protein synthesis to a level comparable to that induced by 25 g of whey protein.”

In other words, if you drink a whey protein shake that’s augmented with BCAAs, that’s a good thing, but taking them alone probably isn’t a great strategy for muscle recovery.

Do they fight off fatigue?

Supposedly, yes. This happens because they use the same carrier system as tryptophan, an amino acid that travels to the brain where it helps create serotonin, which causes fatigue. In other words, tryptophan calls an UberX Share to get to your brain, but when he opens the door, leucine, isoleucine, and valine are already inside and they’re all, “Sorry! This Prius is full!” so tryptophan is delayed getting into your head. No fatigue for you!

There’s plenty of research showing BCAAs may sandbag fatigue effectively. In one Swedish study, athletes who supplemented with a BCAA and carbohydrate mix showed an improved ability to performing a “color word test” after completing a 30-km race—because who doesn’t want to play board games after running a hard 18 miles? Another study on endurance-trained cyclists showed BCAA supplementation caused lower perceived exertion and mental fatigue, although there was no difference in performance.

Should you take BCAA supplements? Maybe... For the record, if you eat a balanced diet with adequate protein, you should be getting plenty of them. Also, from a sports supplement perspective, they’re not a slam dunk clinically like electrolytes, caffeine, and creatine. However, they clearly work for some people, so if you have the money, given them a try. Just don’t pin all your hopes and dreams on their promise.

And if you do try them, please drop me a line and let me know how it worked out!

P.S. Thank you to Greg “G$” Leibert for my awesome new logo! You’re a rock star!

NPB on the Leadville Podcast!

This week, The Leadville 100 Mile Mountain Bike Race Podcast had me back on the show to discuss training your gut for proper race feeding. It’s a topic I covered recently here on in the newsletter.

Hottie and Fatty are amazing hosts and the show is well worth a listen for any cyclist—even when I’m not on!

Check out episode S5E15: Training Your Gut here or wherever you listen to podcasts!