Think of this topic like one of those nesting dolls. Proteins are the largest doll. More than 10,000 different proteins construct our bodies and play a role in many crucial systemic functions. Your body breaks down protein into many small molecules called amino acids; these are the medium doll. Nine of these amino acids are deemed “essential,” since the body can’t make them on their own and we need to get them through food or supplements. And the smallest doll of all are branched-chain amino acids (BCAAs), which are a select subset of three essential amino acids: leucine, isoleucine and valine.
Read on for the skinny and benefits of both amino acids and branched-chain amino acids (BCAAs)—plus whether supplements lead to muscle gains (or losses).
RELATED: Will Counting Macros Help Me Lose Weight?
What are Amino Acids, Exactly?
Let’s dial it back to the basics. The calories we consume come from four macronutrients: fat (9 calories per gram), carbohydrates (4 calories per gram), protein (4 calories per gram) and alcohol (7 calories per gram). The protein we eat through dairy, beans, meat, nuts, seeds, soy and more is then broken down by our gastrointestinal tract into amino acids.
As a refresher, our bodies can’t manufacture essential amino acids, so they must be obtained from foods or supplement sources. They are crucial to help the body synthesize and build protein. (Every cell in the human body needs protein.) Beyond providing structure to our bodies, amino acids offer energy, aid in digestion, plus play a key role in neurotransmitter messages, hormones and enzymatic cues.
The nine essential amino acids include:
- Methionine
- Lysine
- Histidine
- Phenylalanine
- Threonine
- Tryptophan
- Leucine
- Isoleucine
- Valine
The non-essential amino acids, which can be produced by our bodies irregardless of whether we ingest them through food, include:
- Alanine
- Asparagine
- Aspartic Acid
- Glutamic Acid
Conditionally essential amino acids are typically non-essential, except in times of illness or stress. They include:
- Arginine (essential for kids, but not adults)
- Cysteine
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine
Each amino acid plays a separate role within the body. For instance, tryptophan aids in serotonin creation to promote high-quality sleep.
BCAA 101, and Who Might Benefit From Them
The three BCAAs actually do the lion’s share of the work creating 35% of our body’s muscle proteins. In supplemental form, BCAAs are digested and absorbed even quicker than they are through some foods. This is why many athletes and bodybuilders take them in powder form while training, typically as either whey protein or casein protein. They act fast and are metabolized in quick order by skeletal muscles; skipping the liver to head straight into the bloodstream.
But while we know BCAAs play a role in the way our bodies create muscle, we don’t definitively know whether supplementing with them leads to strength gains. Research findings on the subject have been contradictory.
A 2016 study published in the American Journal of Physiology-Cell Physiology found that, compared to a placebo, those who consumed BCAAs after resistance training noticed quicker repair and recovery while building more muscle.
But a recent review of the research found BCAA supplementation alone doesn’t promote muscle growth. One small study showed that the biggest bang for the protein buck came when BCAAs were paired with other essential amino acids.
RELATED: Should You Take Branched-Chain Amino Acids if You Want to Get Stronger?
Research has also shown that in supplemental form, casein protein as found in many protein powders may be best for athletes in need of a protein boost. Unlike whey (the other milk protein), casein is more slowly digested and provides a sustained release of amino acids.
BCAAs can, of course, be obtained through diet. Foods that contain BCAAs include:
- Meat, poultry, fish
- Eggs
- Dairy
- Nuts and seeds
- Soy, such as tofu and tempeh
- Legumes
It’s important to note that the majority of Americans already easily exceed our minimum protein intake needs. So with that in mind, and especially since we’re always of a food-first mindset here, if you can cover your protein bases through food, that would be the best route.
The Bottom Line
Those who are vegan, fasting (ahem, not recommended for these populations) or facing an illness may benefit from additional essential amino acids and BCAAs in supplemental form. Consult with a dietitian before beginning a new supplement, amino acid or otherwise.
If you don’t fall into one of those categories, aim to obtain a wide variety of protein within two hours of exercise through sources such as:
- Grass-fed beef
- Quinoa
- Eggs
- Turkey
- Yogurt
- Seafood
- Cottage cheese
- Chia seeds
- Milk
Remember, you absolutely *can* overdo it on protein consumption. So spread it out throughout the day in 25- to 30-gram doses, and consult with a nutrition coach or dietitian if you feel like you’re falling short or notice any muscle loss.
(Images: Shutterstock)
