Vegan Amino Acids: Protein and Plant-based Diets

A common question that people ask is how vegans get enough protein in their diet. Interestingly, humans don’t require protein, but instead require essential amino acids that are found in foods containing protein.

There’s an abundance of protein in plant-based foods, but if you grew up relying on animal protein, it’s understandable to question sources of vegan protein.

Vegan sources of protein and lysine: protein and amino acids for vegans

Jump to:

What is Protein? What are Amino Acids?
What Protein and Amino Acids Do in the Body
How Much Protein Do Humans Need?
How Much Protein Do Vegans Need?
What Amino Acids are Vegans Missing?
How to Get Enough Protein and Amino Acids as a Vegan
High Protein Vegan Recipes
Summary: Protein and Amino Acids for Vegans

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What is Protein? What are Amino Acids?

Amino acids are small molecules, each with unique shapes and properties. Amino acids join to form long chains. These chains group into larger molecules called protein.

Protein is an essential macronutrient; however, it’s not specific proteins that the body needs. Our bodies need individual amino acids.

There are 20 different amino acids but only 9 are considered essential ¹. These 9 are essential because the body cannot make them, whereas it can produce enough of the other 11 ¹.

Anything the body needs to function, but cannot produce, is considered essential and you must get it through diet or supplementation.

What Protein and Amino Acids Do in the Body

When eating food that contains protein, the body breaks down protein into individual amino acids ².

These amino acids are then absorbed through the intestine and transported to cells in the body via the blood stream ².

Once a cell gets amino acids, it can use those to create all the necessary protein molecules that make the body function. There are thousands of different protein molecules the body makes, each with its own important function ².

Protein is essential for most, if not all, body functions including: ²^,³

Growth, repair, maintenance: Protein helps grow, repair and maintain cells in the body including organs, muscles, bones, skin and hair.
Immune system: The immune system includes proteins that protect the body from infections and other diseases.
Transportation: Proteins transport other molecules through the blood stream and in or out of cells.
Fluid balance: Protein helps keep the body’s fluids where they need to be (for example, preventing fluids from pooling in the legs or feet).
Hormones: Some proteins act as hormones (messenger molecules that allow cells to talk to one another).
Enzymes: Enzymes are proteins that make reactions happen faster and more efficiently, keeping everything in the body working smoothly.
Electrolyte balance: Proteins keep electrolytes where they need to be so functions like muscle contraction and nerve signaling can happen.
Fertility: Adequate protein is needed for fertility, and protein needs are increased during pregnancy and lactation.
Provide energy: If consuming excess protein, the amino acids are converted into energy (meaning protein is a source of calories).

Proteins do a lot in the body. This is a short, simplified list.

Infographic with shot points about what protein does in the body.

How Much Protein Do Humans Need?

The current recommendation for protein intake (in average, healthy adults) is 0.8 grams of protein per kilogram of body weight, per day ⁴.

To use this formula, multiply your weight in kilograms by 0.8. The number you get represents how many grams of protein to eat per day based on this recommendation ⁴.

Older adults likely have higher protein intake requirements ⁶^,⁷. One review suggests an intake range of 1.0-1.2 grams/kilogram for healthy older adults. For older adults with malnutrition or illness, 1.2-1.5 grams/kilogram might be appropriate ⁷.

Leucine may be an amino acid of particular importance for older populations ⁸. Luckily, this amino acid doesn’t seem to be limited in high-protein foods (including plant-based proteins) ⁸.

I’ve seen people interpret this formula as 0.8 grams of protein per pound of body weight. This is incorrect; using pounds results in more than double what’s actually recommended ⁴.

Protein Recommendations Debate

There is debate over protein intake recommendations. Many people believe that 0.8 grams of protein per kilogram of body weight per day is simply not enough.

One review suggests the methods used to calculate 0.8 grams/kilogram were faulty ⁵. The authors suggest that using more appropriate methods, an acceptable amount of protein would be 1.0-1.2 grams of protein per kilogram of body weight per day ⁵ .

Other reviews also suggest higher protein needs ²^,⁸.

The suggested amount of 0.8 grams/kilogram is likely best treated as a minimum value ²^,⁶.

With physical activity factored in, most humans need 1.0-1.6 grams of protein per kilogram of body weight per day, with higher amounts for more physically active people ²^,⁶^,⁸.

How Much Protein Do Vegans Need?

A note in my protein intake recommendation reference states:

“Available evidence does not support recommending a separate protein requirement for vegetarians who consume complimentary mixtures of plant proteins, as these can provide the same quality of protein as that from animal proteins.” ⁴

To date, I haven’t seen research specifically measuring protein intake requirements in vegans. Therefore, it’s likely that general recommendations are adequate for vegans.

Given the debate over protein intake requirements, I aim for the slightly higher intake of 1.0-1.2 grams per kilogram of body weight and use the 0.8 grams/kilogram as a minimum target.

Everyone has different needs, so if you have any concerns about your protein intake, speak with your primary care provider or a Registered Dietitian.

Infographic with high protein vegan foods listed.

What Amino Acids are Vegans Missing?

There is some debate over the “quality” of plant-based proteins. This refers to the amino acid composition of plant protein in comparison to animal proteins, and the digestibility of plant-based vs animal proteins ⁶.

It’s generally thought that animal foods contain all essential amino acids, whereas plant-based foods are missing certain amino acids. This is not true.

Plant-based proteins contain all 9 essential amino acids.

However, certain sources of plant-based protein may be lower in one or more amino acids ⁶^,⁸. Legumes tend to be lower in the amino acid methionine and some report legumes also being lower in cysteine ⁶^,⁸. Most other plant-based proteins are lower in the amino acid lysine (grains, for example) and possibly tryptophan ⁶^,⁸.

This has led to decades of recommendations for vegetarians and vegans to “combine” legumes with other high protein foods, to get a full array of amino acids.

This topic is reviewed in my article about protein combining, but the short story is, protein combining is not strictly necessary. Eating a variety of plant-based protein including legumes, nuts, seeds and grains should provide adequate protein and amino acids ⁹^,¹⁰^,¹¹.

Lysine could be a concern if the diet lacks legumes (beans, lentils, soy) ¹⁰^,¹¹. Vegans should take some care to ensure they consume enough lysine (see tables below for lysine content in plant-based foods).

Lysine Intake Recommendations

Lysine recommendations vary by source, but typically fall into the range of 30-38 milligrams of lysine per kilogram of body weight/ day ¹²^,¹³.

Erring on the side of caution, I prefer to use the higher amount of 38 milligrams/ kilogram of body weight. This is the amount the USDA determined to be a recommended daily intake to meet the needs of 98% of the population ¹³. To use this formula, multiply your weight in kilograms by 38. The resulting number is the milligrams of lysine recommended per day.

You can also divide this number by 1000 to get the amount of lysine in grams per day. I’ve reported the lysine content of foods below in grams, so this is a helpful conversion to do.

The 9 Essential Amino Acids

Getting enough amino acids in a vegan diet shouldn’t be concern, assuming you regularly consume a variety of protein-rich foods.

However, for curiosity’s sake, here are the recommended intake amounts for all 9 essential amino acids (all reported as milligrams of the amino acid per kilogram of body weight per day): ¹³

Lysine: 38 mg/kg/d
Histidine: 14 mg/kg/d
Isoleucine: 19 mg/kg/d
Leucine: 42 mg/kg/d
Methionine: 19 mg/kg/d
Phenylalanine: 33 mg/kg/d
Threonine: 20 mg/kg/d
Tryptophan: 5 mg/kg/d
Valine: 24 mg/kg/d

How to Get Enough Protein and Amino Acids as a Vegan

While people are often concerned about getting enough protein when transitioning to a vegan diet, this shouldn’t be too much of a worry.

Consuming protein throughout the day may be the best method to ensure adequate intake ⁶. Spreading protein intake through the day can help maximize how much is absorbed and used ⁶.

For example, eating 3-4 meals containing moderate amounts of protein, rather than 1-2 meals with very high amounts of protein.

Below is a list of some plant-based foods and the amount of total protein and lysine they contain ¹⁴. Hopefully, by scrolling through this list, it becomes clear that protein intake can easily add up through the day as it’s present in many foods.

To meet lysine requirements, aim for 3-4 servings of higher lysine foods each day. Legumes (beans, lentils, soy) are typically the best sources of lysine.

If you don’t often eat these foods, look carefully at the lysine content of the foods you do eat to make sure it adds up to meet your intake needs.

A common mistake I see new vegans make is replacing meat in their favorite meals with vegetables. While vegetables contain some protein, unless higher protein foods are also included regularly, you can fall short of protein and/or lysine intake needs.

Cauliflower, eggplant, jackfruit, mushrooms and other veggies can be delicious meat-alternatives, but they are not high in protein or lysine. Occasionally, eating meals that are lower in protein is okay, but doing this on a regular basis may not be ideal.

Protein content is rounded to the nearest whole number and lysine content is rounded to one decimal place ¹⁴.

Protein and Lysine Content of Legumes (Including Soy)

Food (serving size) ¹⁴	Protein (grams) ¹⁴	Lysine (grams) ¹⁴
Black beans, boiled (125 mL/ 91 g)	8	0.5
Chickpeas, boiled (125ml/ 87 g)	5	0.3
Kidney beans, boiled (125 mL/ 94 g)	7	0.5
Lentils, boiled (125 mL/ 105 g)	9	0.7
Edamame, boiled (125 mL/ 95 g)	12	0.7
Pinto beans, boiled (125 mL/ 90 g)	6	0.4
Black-eyed peas, boiled (125 mL/ 90 g)	7	0.5
Refried beans, canned (125 mL/ 133 g)	7	0.5
Tofu, firm, raw (125 mL/ 131 g)	11	0.7
Tempeh (125 mL/ 88 g)	16	0.8
Soy beverage, enriched (125 mL)	4	0.1
Peanuts, raw (100 mL/ 62 g)	16	0.6
Peanut butter, natural (30 mL/ 2 tbsp)	7	0.3
Hummus, commercial (60 mL/ 62 g)	5	0.2
Peas, boiled (125 mL/ 85 g)	5	0.3

Protein and Lysine Content of Nuts and Seeds

Food (serving size) ¹⁴	Protein (grams) ¹⁴	Lysine (grams) ¹⁴
Almonds (100 mL/ 58 g)	12	0.3
Cashews (100 mL/ 59 g)	9	0.5
Walnuts (100 mL/ 50 g)	8	0.2
Pecans (100 mL/ 46 g)	4	0.1
Hazelnuts/ filberts (100 mL/ 57 g)	9	0.2
Macadamia nuts (100 mL/ 57 g)	4	0.01
Brazil nuts (100 mL/ 59 g)	8	0.3
Pistachios (100 mL/ 52 g)	11	0.6
Hemp seeds (60 mL/ 40 g)	13	0.5
Flax seeds, whole (60 mL/ 43 g)	8	0.4
Flax seeds, ground (60 mL/ 28 g)	5	0.3
Chia seeds (60 mL/ 43 g)	7	0.4
Pumpkin seeds, roasted (60 mL/ 58 g)	17	0.7
Sesame seeds (60 mL/ 33 g)	6	0.2
Sunflower seeds, hulled (60 mL/ 36 g)	7	0.3

Protein and Lysine Content of Grains (Including Wheat Gluten)

Food (serving size) ¹⁴	Protein (grams) ¹⁴	Lysine (grams) ¹⁴
Brown rice, cooked (125 mL/ 103 g)	3	0.1
Wild rice, cooked (125 mL/ 87 g)	3	0.1
White rice, long grain, cooked (125 mL/ 84 g)	2	0.1
Oats, large flakes, cooked (125 mL/ 123 g)	4	0.1
Quinoa, cooked (125 mL/ 98 g)	4	0.2
Couscous, cooked (125 mL/ 83 g)	3	0.1
Whole grain bread, commercial (1 slice)	4	0.1
White bread, commercial (1 slice)	3	0.1
Whole wheat pasta, cooked (125 mL/ 74 g)	4	0.1
White/ regular pasta, enriched, cooked (125 mL/ 74 g)	4	0.1
Buckwheat groats, cooked (125 mL/ 89 g)	3	0.2
Barley, pearl, cooked (125 mL/ 83 g)	2	0.1
Vital wheat gluten (20 g)	15	0.4
Corn, yellow, frozen and cooked (125 mL	2	0.1

Protein and Lysine Content of Select Vegetables

Food (serving size) ¹⁴	Protein (grams) ¹⁴	Lysine (grams) ¹⁴
Mushrooms, white (125 mL/ 51 g)	2	0.1
Mushrooms, Portobello (125 mL/ 115 g raw or 64 g grilled)	2	0.1
Eggplant, raw or boiled (250 mL/ 87 g)	1	0.04
Jackfruit, raw (125 mL/ 87 g)	1.5	0.06
Cauliflower, raw or boiled (125 mL/ 57 g)	1	0.1
Beets, boiled (125 mL/ 90 g)	2	0.05
Kale, raw (250 mL/ 71 g)	3	0.1
Broccoli, boiled (125 mL/ 82 g)	2	0.1
Spinach, raw (250 mL/ 32 g)	1	0.06
Potato, boiled with skin, flesh eaten (100 mL/ 66 g)	1	0.08
Sweet potato, baked, skin removed after baking (100 mL/ 85 g)	2	0.07
Carrot, boiled (125 mL/ 82 g)	1	0.07
Winter squash, baked (125 mL/ 108 g)	1	0.04
Green or yellow beans, boiled (125 mL/ 71 g)	1	0.05

High Protein Vegan Recipes

Here’s some of my favorite high-protein recipes for meals throughout the day! I selected a variety of recipes for each category, featuring different sources of plant-based protein.

Some of the recipes below are complete meals on their own, while others need to be paired with side dishes to round out the meal. These other foods likely offer some extra protein too (for example, adding a side of peas, carrots and potatoes to the seitan roast).

Breakfast

Lunch

Tofu Frittata (14 g)
Edamame Falafel (17 g)
BBQ Pizza (23 g)
Broccoli Potato Soup (13 g)
Chickpea Salad Sandwich (13 g)
Greek Salad with Tofu Feta Cheese (15 g)

Dinner

Lentil Walnut Taco Meat (18 g)
Red Curry Pasta (26 g)
Gyros (28 g)
Seitan Roast (28 g)
TVP Shepherd’s Pie (22 g)
Sushi Bowls (25 g)
Burrito Bowls (22 g)
Lasagna (27 g)
Chow Mein (27 g)

Appetizer

Summary: Protein and Amino Acids for Vegans

Vegans should be able to meet their protein intake needs through a balanced diet that includes a variety of high-protein foods. Legumes, grains, nuts and seeds provider higher amounts of protein while vegetables provide smaller amounts.

Lysine may be an amino acid for vegans to pay attention to as it can be limited in certain sources of plant-based protein. Legumes (beans, lentils, soy) are the plant-based foods highest in lysine, although certain nuts and seeds have good amounts of lysine as well.

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