Most of us may know that amino acids are essential protein building blocks, yet they play many dual roles as well, such as synthesizing hormones and neurotransmitters. Recently, amino acids have been extracted and packaged into supplement form for those looking to boost their energy levels or achieve better athletic performance.
For all the health hullabaloo around protein amino acids, how much do we know about these essential substances?
When it comes to practicing a strict plant-based, vegetarian, or vegan diet, this question happens to be crucial to maintaining a healthy balanced diet. Why? Turns out a handful of essential amino acids are found naturally in meat and animal products. Therefore, if you haven’t done your homework, you may be deficient.
Of course, with knowledge comes the power to fill in those amino acid gaps with the appropriate plant-based resources!
There are 20 amino acids, yet for this article, we’re going to target the nine most essential. Out of these nine, some can be found in plant-based foods, and others are animal-based. Let’s take a look at all of these amino acids and how to integrate plant-based sources into your balanced diet!
What Are Amino Acids?
Amino acids are oftentimes referred to as the building blocks of life. This is for a good reason. These organic compounds “combine to form proteins,” which are critical to a healthy, functioning body.
Each of these amino acid sequences gets to determine “each protein’s unique 3-dimensional structure and its specific function.” These functions include breaking down food, growth, and repairing body tissue, among many other essential bodily functions. Along with these tasks, amino acids “can also be used as a source of energy by the body.”
Amino acids are broken down into three distinct groupings: essential, nonessential, and conditional. Conditional amino acids are generally only essential if you are under stress or sick, and these include arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine. Nonessential amino acids are produced by our body, with or without food, and include alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine. Essential amino acids, on the other hand, are labeled as such because our body cannot make them, and therefore we must consume them via diet. The remaining nine essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Plant-Based Sources of the Nine Essential Amino Acids
When it comes to plant-based eating, there are a few sources of all nine essential amino acids, referred to as complete proteins, including quinoa, buckwheat, and soy. Beyond these three foods, other plant-based foods provide some of the essential amino acids, but they aren’t complete. These are protein-rich plant-based foods such as beans, nuts, whole grains, seeds, and some veggies.
Here’s a breakdown of each of the essential amino acids, what they do in the body, and the best plant-based sources!
Histidine produces a neurotransmitter called histamine, which is “vital to immune response, digestion, sexual function, and sleep-wake cycles,” as well as being a critical component “for maintaining the myelin sheath, a protective barrier that surrounds your nerve cells.” Plant-based foods rich in histidine include rice, wheat, rye, beans, quinoa, “buckwheat, corn, cauliflower, mushrooms, potatoes, bamboo shoots, bananas, cantaloupe, and citrus fruits.”
2 and 3. Isoleucine and Leucine
Isoleucine and leucine are both important for the health of your muscles and blood sugar. Specifically, isoleucine is an integral part of muscle metabolism — it’s concentrated within muscle tissue — as well as immune function, hemoglobin production, and energy regulation, and leucine is “critical for protein synthesis and muscle repair,” plus it also “helps regulate blood sugar levels, stimulates wound healing and produces growth hormones.” Both of these amino acids are found in quinoa, buckwheat, and soy, as well as small quantities in “lentils, black beans, and pinto beans,” which “provide just under 0.2 g of leucine and nearly 0.1 g of isoleucine per ounce.”
Lysine, also called L-lysine, is important for “protein synthesis, hormone and enzyme production, and the absorption of calcium,” as well as “energy production, immune function and the production of collagen and elastin.” This amino acid is particularly rare in plant-based foods, yet it can be consumed via tofu and some green leafy veggies including spinach, kale, watercress, romaine lettuce, and swiss chard, as well as the complete proteins quinoa and buckwheat.
Methionine is essential for metabolism, detoxification, tissue growth “and the absorption of zinc and selenium, minerals that are vital to your health.” When it comes to methionine, too much may be unhealthy. This is where a plant-based diet shines! While you can consume small amounts of methionine through brazil nuts, oats, and sunflower seeds (as well as buckwheat and quinoa) a plant-based diet generally delivers just enough to be healthy without overdoing it!
Phenylalanine “is a precursor for the neurotransmitters tyrosine, dopamine, epinephrine, and norepinephrine,” as well as playing an integral role “in the structure and function of proteins and enzymes and the production of other amino acids.” Phenylalanine is found primarily in nuts and legumes — for instance, five walnuts contain 540 mg, and chickpeas, beans, and lentils contain around 400 mg per serving — as well as soybean flour and tofu, and of course buckwheat and quinoa.
Threonine, similar to lysine, is a “principal part of structural proteins such as collagen and elastin, which are important components of the skin and connective tissue,” as well as playing a role in “fat metabolism and immune function.” Similarly to phenylalanine, threonine is found in soy products, — such as soya beans — nuts, — such as almonds, pistachios, and cashews — seeds, — such as pumpkin, chia, and flax — beans, — such as cranberry beans, yellow beans, and kidney beans — and lentils.
Tryptophan maintains “proper nitrogen balance and is a precursor to serotonin, a neurotransmitter that regulates your appetite, sleep, and mood.” Even plant-based eaters are aware that turkey makes you sleepy due to tryptophan levels, but this essential amino acid is also found in plant-based foods. The best plant-based sources of tryptophan include pumpkin and sunflower seeds, cashews, walnuts, almonds, peanuts, split peas, lentils, kidney beans, and black beans.
Valine helps “stimulate muscle growth and regeneration and is involved in energy production.” Valine can be found in soya foods — roasted soybean products such as soy flour, natto, and tempeh — seeds — particularly watermelon seeds, pumpkin seeds, flaxseeds, and sunflower seeds — nuts — such as pistachio, cashews, and almonds — cooked mushrooms — particularly, portobello, white, oyster, and shiitake — whole grains — including Kamut, teff, and wild rice — and a variety of beans and lentils.
As you can see, eating a diverse and well-balanced plant-based diet filled with vegetables, legumes, and grains, is the best way to make sure you’re getting all of those nine essential amino acids. Luckily, there are plenty of recipes that can help you diversify your plate! Here are a few recommendations for each of the essential amino acids. Every essential amino acid has at least one of the complete proteins — buckwheat, quinoa, and tofu — as well as an individual recipe for that specific amino acid.
When it comes to histidine, I chose to highlight corn. Not only is this a wonderfully sweet and fun-to-eat plant-based food, but corn is also super easy to prep and cook. Enjoy it right off the cob or mix it into a more colorful and rich recipe such as this Easy Corn Salad with Sriracha and Lime. Fore more histidine in your diet, try starting your day with these Blueberry Scones (buckwheat), this Apple Cinnamon Quinoa Porridge (quinoa), or this Tofu Scramble and Collard Greens (soy).
For isoleucine and leucine, try pinto beans. They are a wonderful buttery bean that is easy to cook and is oftentimes already a staple in your pantry. Plus, they can be emulsified or mashed into a meaty texture, great for meatless recipes such as this Smokey Pinto Bean-Beet Burgers recipe. For a full day of isoleucine and leucine consumption, try awakening with this Balanced Breakfast Bowl (tofu) or this Healthy Golden Curried Quinoa (quinoa) — perk up midday with this Flavored Gluten-Free Tortilla (buckwheat) or this Kale, Quinoa, and Radish Salad (quinoa) — whip up this easy Sweet and Sour Tofu (tofu) dinner recipe and then end the day with something sweet and filled with healthy nutrients, Mocha Chocolate Brownie Bites (buckwheat).
Watercress is one of those veggies that you may know the name of, but you have no idea what it is! This aquatic plant is a close “cousin to mustard greens, cabbage, and arugula,” and is an excellent ingredient to have handy for salads, meatless burgers, and even your morning oats. It’s also a great source of lysine, such as in this Smoky Chickpea and Watercress Salad. Get more lysine with this Buckwheat Breakfast Bowl (buckwheat), this Spicy Quinoa and Black Bean Tortilla Soup (quinoa), or this Chilli Peanut Tofu (tofu).
I recently wrote an article outlining the health benefits of selenium and one of the richest, best plant-based sources are brazil nuts. Turns out, brazil nuts are also a great place to get your daily dose of methionine! For a sweet methionine, treat try these Raw Coconut and Brazil Nut Truffles. Along with these truffles, you can get methionine from these Coconut Creamed Beet Greens with Toasted Buckwheat and Macadamia Nuts (buckwheat), these Chocolate Pretzel Quinoa Bars (quinoa), or this sweet and savory Chicken-Fried Tofu With Orange-Scented Sweet Potatoes (tofu).
Walnuts are not only a great source of healthy fats — the omega’s in particular — but they are also one of the best plant-based sources of phenylalanine. Their rich, meaty, and malleable texture makes them perfect for healthy bread options such as this Black Bean, Quinoa, and Walnut Loaf. Get more phenylalanine out of your day with this morning Crêpe Bretonne (buckwheat), these Mini Quinoa-Chickpea Cakes (quinoa), or this Tofu ‘Shrimp’ Scampi (tofu).
Ever heard of yellow beans? Me either! That’s why I’ve decided to highlight them here. Yellow beans, also referred to as yellow wax beans, are nearly identical to green beans except for the fact that they have a pale cornflower color and they are a great source of threonine, such as in this Italian Yellow Flat Beans With Olive Oil, Garlic, and Tomatoes. More sources of threonine include these Buckwheat Pies with Chicory and Olives (buckwheat), this festive Southwest Quinoa Salad (quinoa), or this healthy Avocado Tofu Chocolate Mousse (tofu) treat!
Pumpkin seeds are one of my all-time favorite plant-based foods. They are rich in healthy fats and contain a slew of nutrients. Plus, they are a tasty addition to almost any dish, including salads, veggie bowls, sautees, and even desserts. Pumpkin seeds are also a great source of tryptophan, which you can have at the ready with this Homemade Pumpkin Seed Milk recipe! Get more of your calming tryptophan with these Buckwheat Pumpkin Pancakes (buckwheat), this Grilled Zucchini and Corn Quinoa Salad With Toasted Pepitas and Lemon Mint Dressing (quinoa), or this Tofu Pad See Ew (tofu).
For valine, I decided to go with another plant-based food item that was somewhat unfamiliar. Kamut, also called Khorasan wheat and pharaoh grain, is a grain product that is a healthier option than traditional wheat owing this fact to its 30 percent higher protein content lending to its valine. Plus, Kamut is great to cook with, such as in this Slow Roasted Leeks With Toasted Grains and Pesto. For more valine, try this Minestrone Soup with Pumpkin and Buckwheat (buckwheat), this Carrot and Kale Quinoa Patties (quinoa), or this Crispy Battered ‘Fish’ (tofu).
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