Trying to pin down amino acid functions is a challenge, as these nutrients along with protein form the foundation for all human life. They are involved in numerous metabolic and functional processes. You'll find amino acids in a wide range of meats, vegetables and even fruits.
Amino Acid Functions and Types
Amino acids are considered one of your body's energy sources, states the U.S. National Library of Medicine. These compounds form different types of proteins. When structurally complete, protein helps your body digest and metabolize food and perform its daily functions.
When your body's tissues are damaged, proteins play a major role in the repair process. These nutrients also contribute to the smooth operation of numerous bodily functions.
Three groups of amino acids, each with their roles, have been identified. First up are the nine essential amino acids, which the body can't produce on its own. To meet your body's needs, you must eat foods that contain those compounds.
Next, consider the 11 non-essential amino acids that can be derived from two sources. Besides getting these nutrients from food, your body has the ability to make them.
Finally, the eight conditional amino acids aren't usually necessary at all times. In certain circumstances, these compounds help your body cope with stress or recover from illness.
To meet your body's daily requirements for essential amino acids, you don't need to consume all of them in one meal. Instead, eat a balanced diet, one rich in foods that contain these compounds, and you should receive sufficient quantities of these nutrients.
Meeting your body's non-essential amino acids requirements might be more complicated. In a June 2015 study published in Experimental Biology and Medicine, researchers note evidence that humans need sufficient quantities of non-essential amino acids to achieve genetic growth, reproduction and disease resistance targets.
It has previously been assumed that humans can synthesize enough non-essential amino acids to meet these pre-established goals. However, researchers haven't found convincing proof that humans produce enough non-essential amino acids to meet their bodies' ongoing needs. This finding would seem to open the door for new ways to meet these milestones.
The Amino Acid-Protein Connection
Because amino acids combine to form life-sustaining proteins, it's useful to consider the role of protein in overall health. According to the Harvard T.H. Chan School of Public Health, this macronutrient helps form and maintain your bones, muscles, skin, hair and other tissues.
Protein also forms the enzymes that drive many of your body's chemical reactions and aids in the production of hemoglobin, which helps transport oxygen in the bloodstream. In fact, more than 10,000 proteins work in harmony to keep your body in operating condition.
So, how much protein does your body need every day? Per the National Academy of Medicine, daily protein requirements depend largely on your body weight. Your physical activity level is also a factor to consider. The more active you are, the higher your protein intake should be.
For example, a 140-pound adult needs roughly 50 grams of protein daily. If you weigh about 200 pounds, you should consume approximately 70 grams of protein every day. To meet those requirements, protein should comprise 10 percent to 35 percent of your daily calories.
Diverse Sources of Amino Acids
Since amino acids make up proteins, these compounds are present in protein-rich foods. Two types of proteins are consistent sources of amino acids, states Rachel Stockle, RDN, a functional-medicine dietitian with the Cleveland Clinic.
For starters, integrate complete proteins into your diet. A complete protein incorporates stable proportions of all nine essential amino acids that your body cannot produce by itself.
Complete proteins are also excellent sources of amino acids. Examples include animal-based foods such as beef, poultry, pork, fish, eggs and dairy products. Whole soy foods, such as tofu, tempeh, miso and edamame, also qualify as complete proteins. Certain grains, especially pseudocereals like quinoa, are also complete proteins.
In contrast, incomplete protein foods contain some essential amino acids but don't have all nine of them. Additionally, dietary amino acids are present in varied proportions rather than the predictable amounts found in complete proteins.
Incomplete protein sources include nuts, seeds, many whole grains, vegetables and legumes, such as peas, beans and lentils. These foods are often staples of vegetarian and vegan diets.
Read more: 13 Surprising Vegetarian Sources of Protein
How to Use Incomplete Proteins
Meeting your daily protein needs using incomplete proteins takes some extra planning, but it's certainly feasible. The Oklahoma Cooperative Extension Service refers to these plant-based proteins as "lower-quality proteins." Note that the terms "incomplete proteins" and "lower-quality proteins" both refer to plant-based protein sources.
Plant-based incomplete proteins don't offer a balanced amount of all nine essential amino acids. In fact, most vegetables and fruits aren't very good protein sources, with a few exceptions.
Foods, such as lentils, split peas, nuts, seeds and some grains, are more desirable sources of protein. However, even these have lower-than-optimal amounts of the essential amino acids.
If you don't consume animal products, eating multiple plant-based foods the same day should help you to get the desired amount and balance of essential amino acids. For example, a peanut butter sandwich, rice and beans dish, or bean and corn casserole each combine foods from different plant groups, so you can still adequately meet your daily amino acids needs.
If animal-based proteins are part of your eating plan, you have an additional option. Add a small portion of animal-based protein to a larger quantity of plant-based protein. You'll obtain a complete protein that satisfies your amino acids requirements. Any type of meat, dairy products and eggs are all good animal-based protein sources.
Try Some Meatless Protein Ideas
Suppose you'd like to try a vegetarian or vegan diet. You want to get creative about meeting your daily amino acid and protein needs and also want to enjoy tasty meals that fit into your healthy lifestyle.
The Vegetarian Nutrition Dietetic Practice Group reiterates that blending legumes and grains to create a complete protein that includes all essential amino acids will certainly work. Nutrition experts previously believed that plant proteins needed to be combined in the same meal to achieve this goal. Because your liver is capable of storing amino acids, eating multiple types of plant foods the same day provides a completely workable solution.
You'll find lots of plant-based foods that score relatively high on the protein scale. Again, consider legumes, vegetables, nuts, seeds and whole grains.
Some whole-grain foods, such as farro and wheat berries, contain up to 11 grams of protein per one-cup serving. Cooked spinach boasts 5 grams of protein per cup, while one cup of cooked peas racks up an impressive 8 grams of protein, points out the Vegetarian Nutrition Dietetic Practice Group.
Consider Plant-Based Meat Alternatives
Maybe your hectic schedule means you have limited time to prepare several plant-based protein foods each day. The Vegetarian Nutrition Dietetic Practice Group suggests that you consider purchasing one or more meat alternatives at your local supermarket or health food store.
With multiple brands jumping into this market niche, you should have a good selection from which to choose. Select from assorted veggie burgers, faux hot dogs, sausage, chicken nuggets and more. Believe it or not, some of these foods are actually quite tasty once they're cooked on the grill or served with healthy toppings.
However, here's a word of caution about commercially prepared meat alternatives. Many of these foods contain high levels of sodium and artificial additives, possibly compromising their potential health benefits.
In contrast, plant-based proteins with little (or no) processing don't have either of these potential negatives or much cholesterol or saturated fat. Additionally, plant-sourced proteins boast impressive amounts of fiber, vitamins, minerals, antioxidants and healthy fats.
Side Effects of L-Arginine Supplements
Amino acids have collectively been recognized for their vital role in building proteins and providing energy for your body. They also have a variety of medical uses, which can result in positive or negative side effects.
For example, the Mayo Clinic notes that L-arginine, present in many complete protein foods, is sometimes used as an oral and topical supplement. As a dietary supplement, this amino acid is generally regarded as safe and has been utilized as a treatment for several medical conditions.
L-arginine has been used to reduce angina symptoms, treat erectile dysfunction resulting from a physical cause and potentially decrease blood pressure levels. However, note that if you take blood pressure medications, it's important to speak with your physician before using L-arginine supplements.
Taking L-arginine orally could also cause some troublesome side effects. You might experience bloating, nausea, abdominal pain and diarrhea. An occurrence of gout is also a possibility. If you've had cold sores or genital herpes, adding L-arginine to your system could stimulate the virus behind those conditions.
If you're dealing with asthma or allergies, L-arginine supplements could make these conditions worse and also potentially cause inflamed airways. If you've had a heart attack, stay away from L-arginine, as taking it could prove fatal.
Are Amino Acid Supplements Necessary?
If you're concerned about getting sufficient quantities of amino acids, Ms. Stockle of the Cleveland Clinic offers an easy-to-implement solution. She suggests that you add a serving of protein powder to your favorite smoothie.
Typically, these blends combine pea protein, rice protein and hemp seed protein. Each of these components has a large percentage of the amino acids your body requires.
The University of New Hampshire adds another perspective on amino acid supplementation. Here, the focus is on branched-chain amino acids (BCAAs), a term that refers to the amino acids' physical structure.
Leucine, valine and isoleucine are the subject compounds, with leucine being the most important because it can generate muscle growth by itself. This attribute is especially important to fitness enthusiasts who may be actively working to strengthen their muscles.
Besides promoting desirable muscle growth, BCAAs have been shown to reduce muscle wasting. These compounds may also relieve muscle soreness, as using them results in a decreased occurrence of exercise-induced muscle damage. Because your body can utilize BCAAs as an energy source, you'll also experience less fatigue.
If you decide to add more BCAAs to your diet, drink a BCAA-infused beverage during or right after your workout. If you regularly consume complete animal-based proteins (or whey protein), you're likely meeting your body's daily amino acids requirements, making BCAA supplements unnecessary.
Branched-Chain Amino Acids Benefits
Branched-chain amino acids, or BCAAs, are the most prevalent essential amino acids, states a March 2018 study published in the International Journal of Molecular Sciences. These hard-working compounds perform a vital role in your body's energy regulation, nutrition, gut health and immune system function.
Researchers emphasized that amino acids have been used as therapeutic agents in gastrointestinal disease treatment, specifically for diarrhea and inflammatory bowel disease. Animal and human research has also indicated that these nutrients play a major role in ensuring optimal intestinal health. These applications add to the list of amino acids benefits.
BCAAs also perform a regulatory role in your immune system. These amino acids regulate specific immune system responses while also ensuring an increased fuel supply for your body's immune cells.
Finally, BCAAs could function as important disease biomarkers. These vital compounds can provide clues to the development of cardiovascular disease and cancer, among other serious conditions. Researchers strongly recommend further studies to determine if BCAAs may also provide advance notice of other chronic diseases.
- U.S. National Library of Medicine: “Amino Acids”
- Harvard T.H. Chan School of Public Health: “Protein”
- National Academy of Medicine: “Dietary Reference Intakes: Macronutrients”
- Cleveland Clinic: “Do I Need to Worry About Eating ‘Complete’ Proteins?”
- Oklahoma Cooperative Extension Service: “Protein and the Body”
- Vegetarian Nutrition Dietetic Practice Group: “Protein in Vegetarian and Vegan Diets”
- Mayo Clinic: “L-arginine”
- University of New Hampshire: “What Are BCAAs?”
- International Journal of Molecular Sciences: “Branched Chain Amino Acids: Beyond Nutrition Metabolism”
- Experimental Biology and Medicine: "Dietary Essentiality of 'Nutritionally Non-essential Amino Acids' for Animals and Humans"