The Only 4 Things You Need to Know About Amino Acids

​News flash: We need protein to live. It’s present in every cell and helps us build and maintain healthy bones, muscle, and skin. Protein, which is found in nuts, seeds, dairy, fish, meat, poultry, and beans, is essentially a long chain of amino acids. So when your body breaks down protein from food, amino acids are what’s left.

There are three types of amino acids: essential, nonessential, and conditional. (Creative, right?) Essential are the kind that can’t be made by your body but are necessary for survival (more on that below). While nonessential seems to imply “not needed,” it actually describes amino acids that your body produces on its own. Conditional amino acids are the kind you usually only need if you’re ill or stressed.

Of the 20 total amino acids, there are nine your body can’t make on its own.

“These amino acids must come from food sources,” says Amy Gorin, R.D. “Without them, the body’s cells would use their own proteins to get those missing amino acids. Eventually, this would lead to degradation of the muscles and organs.” Translation: No bueno for your body.

In case you’re curious, the nine essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Your body needs each of these in different amounts to build muscle, break down food (i.e., digest it), repair tissue, and many other functions. For example, tryptophan (which gets a false bad rap for making you sleepy after Thanksgiving dinner) helps your body make serotonin, a chemical that’s sometimes referred to as a mood-regulating hormone.

You don’t have to go crazy trying to figure out which foods do or don’t have certain amino acids, as long as you’re eating a decent variety of protein sources every day. Gorin offers this example: If you ate plain 2 percent fat Greek yogurt, pistachios, an apple, and whole-grain cereal for breakfast, you’d be getting a small amount of every essential amino acid—and that’s just one meal.

So what about supplements? Read enough health blogs and you’re bound to come across BCAAs, or branched-chain amino acids. There are three BCAAs: isoleucine, leucine, and valine. Because some studies have suggested BCAAs play a role in exercise performance and recovery, they’re popular amongst bodybuilders and athletes, though these findings have been inconsistent.Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. Gualano AB, Bozza T, Lopes De Campos P. The Journal of sports medicine and physical fitness, 2011, Jun.;51(1):0022-4707. Branched-chain amino acid supplementation before squat exercise and delayed-onset muscle soreness. Shimomura Y, Inaguma A, Watanabe S. International journal of sport nutrition and exercise metabolism, 2010, Sep.;20(3):1526-484X. But in general, whole foods are a better choice.

“Speaking for the average athlete—not the Olympian out there—there’s no reason to take a supplement unless there’s a medical indication you need one,” Shaw says. “You can get amino acids from food sources, even as a vegetarian, and still build your muscles.”

If you’re still interested in supplementation, it’s best to speak with a doc or dietitian before starting.

You’ve probably heard that rice and beans are a complete or complementary protein, meaning that when you eat them together, you get all essential amino acids at once. Separately, each is considered an incomplete protein, meaning it’s low in one or more essential amino acid. Researchers used to believe that incomplete proteins needed to be eaten together (at the same meal in a single sitting) in order for your body to best use them. But that’s no longer valid.

“You don’t need to eat the complementary proteins in the same meal,” Gorin says. “So if you have a salad with black beans at lunch and a stir-fry over brown rice for dinner, you’re getting those complementary proteins in the same day.”

But she also stresses: Don’t overthink this. “What’s more important is including a protein source—such as chicken, salmon, eggs, Greek yogurt, tofu—with every meal,” Gorin says. If you’re eating a balance of protein sources, healthy fats (think nuts or avocados), and whole grains (think brown rice or 100 percent whole-grain bread), you’re probably getting a healthy balance of amino acids, Gorin says.