Protein is the most common topic when talking about vegan nutrition. What’s all the fuss about?
Humans need to ensure they meet their protein needs to stay healthy. But what are those protein needs and can we get enough protein on a vegan diet? Keep reading to learn:
- What is Protein? What are Amino Acids?
- What Protein and Amino Acids and Protein Do in the Body
- Daily Intake Recommendations for Protein
- How to Consume Enough Protein and Amino Acids on a Vegan Diet
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What is Protein? What are Amino Acids?
Amino acids are small molecules, each with unique shapes and properties. Protein is a long chain of amino acids. The amino acids get strung together, then are folded up, creating a molecule we call protein.
Protein is an essential nutrient however, it’s not the actual protein that humans require. Our bodies actually need the individual amino acids.
There are many different amino acids but only nine of them are considered essential. They are essential because the body cannot make them. If we can’t make the amino acids we need, we must get them into our body by eating/ drinking them!
What Amino Acids and Protein Do in the Body
When we eat a food that contains protein, the body breaks that protein up into individual amino acids. These amino acids are then absorbed through the intestine and transported to all the cells in the body via the blood stream.
One a cell gets amino acids, it uses those amino acids to create all the necessary protein molecules that make the body function.
There are thousands of different protein molecules the body makes, each with it’s own important function including:
- Growth, repair, maintenance: Protein is needed to grow, repair, and maintain the cells in your body including all organs, muscles, bones, skin and hair.
- Transportation: Proteins transport other molecules through our blood stream and in or out of cells.
- Fluid balance: Protein helps keep the body’s fluid where it needs to be (for example, keeping fluids from pooling in legs or feet).
- Hormones: Some proteins act as hormones aka messenger molecules that allow cells to talk to one another.
- Enzymes: Enzymes are proteins that make reactions in our body happen faster and more efficiently.
- Electrolyte balance: Proteins keep electrolytes where they need to be so things like muscle contraction and nerve signaling can happen.
- Provide energy: Excess protein is broken down and used as energy (meaning protein is a source of calories).
Proteins do a lot in our body. We need to make sure our body has enough of the essential amino acids, to make the correct proteins, to get the job done.
Daily Intake Recommendations for Protein
The Health Canada recommended dietary allowance for protein is 0.80g/kg per day for adults over the age of 19 years 1. This recommendation is for average, healthy adults (some people need different amounts for different conditions; please speak to your registered dietitian or doctor). As a general example, a person who weighs 68 kg (150 lbs), would need ~54.4g of protein each day (0.80g x 68 kg = 54.4g) based on this recommendation.
There is debate in the nutrition community over this recommended amount of protein. Many people believe that 0.80g/kg is not enough for optimal function and health. However, this is the amount that was deemed acceptable to meet the needs of 98% of the population, therefore is a good minimum target to aim for.
One review suggests the methods used to calculate 0.80g/kg were faulty. The authors suggest by using more appropriate methods, an acceptable amount of protein would be 1.0-1.2g/kg per day 3. This is something to keep in mind when working to determine an appropriate protein intake target for an individual, ideally with the support of a Dietitian. Always consult a doctor before making any changes to your diet.
Protein Intake Recommendations for Vegans
The 0.80g/kg recommendation comes from studies on the general population, most of whom would have been consuming some type of animal protein. Do vegans, or those consuming mostly plant-based protein, need a larger quantity? There is a special note in the Dietary Reference Intake tables that 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.” 1
That being said is great, but there haven’t been any large-scale studies of vegans and the protein balance in their bodies. For a great review of the available evidence, check out this article here 2.
In summary, it’s generally recommended to aim for a minimum of 0.80g/kg of protein per day. Eating 1.0-1.2g/kg per day may be a more accurate target range. If you need personalized help to determine your protein needs, speak with a Dietitian, and always consult a doctor before making any changes to your diet.
Note: I’ve seen many people recommend 0.80 – 1.0 g/lb (grams per pound). The official recommendations (in Canada) use kilograms not pounds. Using pounds will generate protein recommendations that are more than double the value of using kilograms.
Amino Acid Intake Recommendations for Vegans
There are two essential amino acids that are lower in some plant-based protein sources 6. Legumes tend to be lower in the amino acid methionine, and most other plant-based proteins are lower in lysine.
This doesn’t mean that legumes, or other plant-based sources of protein are of low quality or incomplete. All whole plant-based foods contain both methionine and lysine, to varying extents.
Since methionine is available in enough quantity in most plant-based protein sources, it’s likely not a concern for a plant-based or vegan diet 6. If you are meeting your protein needs through a variety of foods, you should be meeting your methionine requirements. However, lysine could be a limiting amino acid for plant-based or vegan diets. A bit of care needs to be taken to ensure you are eating enough lysine 6.
Lysine Intake Recommendations
The U.S. recommendation for lysine intake is set at 38mg/kg per day for adults over 19 years 2, 4. Going back to our example of a 68 kg (150 lbs) adult, they would require 2.58g of lysine per day based on this recommendation.
How to Consume Enough Protein and Amino Acids on a Vegan Diet
Below is a list of some plant-based foods and the quantity of total protein and lysine they contain. As you scroll through, you may notice that total protein can easily add up through the day, if you eat a variety of the foods listed. Vegetables and fruits also provide smaller amounts of protein that can be included in this total.
To meet lysine requirements, it would be important to eat at least 3 servings of the higher-lysine foods for the average, healthy person. Legumes are typically higher in lysine whereas grains, nuts and seeds are often lower. Incorporating 2-3 servings of legumes everyday can be a great way to meet lysine requirements as a vegan.
This data was pulled from the Canadian Nutrient File database 5 unless otherwise noted.
Serving size notes: I’ve tried to keep the serving size for similar foods the same, for easy comparison. This wasn’t always possible due to the data source I was using.
Protein and Lysine Content of Legumes (including soy)
| Food | Protein (g) | Lysine (mg) |
|---|---|---|
| Black beans, boiled (125mL) | 7.65 | 0.54 |
| Chickpeas, boiled (125mL) | 5.35 | 0.34 |
| Kidney beans, boiled (125mL) | 6.78 | 0.47 |
| Lentils, boiled (125mL) | 9.44 | 0.66 |
| Edamame, boiled (125mL) | 11.74 | 0.70 |
| Pinto beans, boiled (125mL) | 6.28 | 0.40 |
| Black-eyed peas, boiled (125mL) | 7.34 | 0.50 |
| Refried beans, canned (125mL) | 6.75 | 0.50 |
| Tofu, firm, raw (150g) | 12.28 | 0.69 |
| Tempeh, raw (150g) | 27.81 | 1.36 |
| Soy beverage, enriched (125mL) | 3.7 | 0.10 |
| Peanuts, raw (100mL/62g) | 15.92 | 0.571 |
| Peanut butter, natural (30mL/ 2 tbsp) | 7.45 | 0.27 |
| Hummus, commercial (60mL/ ¼ cup) | 4.93 | 0.182 |
| Peas, boiled (125mL) | 4.53 | 0.27 |
Protein and Lysine Content of Nuts and Seeds
| Food | Protein (g) | Lysine (mg) |
|---|---|---|
| Almonds (100mL/58g) | 12.23 | 0.33 |
| Cashews (100mL/59g) | 8.87 | 0.47 |
| Walnuts (100mL/50g) | 7.72 | 0.22 |
| Pecans (100mL/46g) | 4.22 | 0.13 |
| Hazelnut/ filbert (100mL/57g) | 8.53 | 0.24 |
| Macadamia nut (100mL/57g) | 4.48 | 0.01 |
| Brazil nut (100mL/59g) | 8.47 | 0.29 |
| Pistachios (100mL/52g) | 10.54 | 0.59 |
| Hemp seeds (60mL/40g) | 13.28 | 0.46 |
| Flax seeds, whole (60mL/43g) | 7.79 | 0.37 |
| Flax seed, ground (60mL/28g) | 5.19 | 0.25 |
| Chia seeds (60mL/43g) | 7.15 | 0.42 |
| Pumpkin seeds (pumpkin and squash seeds, roasted) (60mL/58g) | 17.18 | 0.70 |
| Sesame seeds (60mL/33g) | 5.51 | 0.18 |
| Sunflower seeds, hulled (60mL/36g) | 7.38 | 0.33 |
Protein and Lysine Content of Whole Grains (including wheat gluten)
| Food | Protein (g) | Lysine (mg) |
|---|---|---|
| Brown rice, cooked (125mL/103g) | 2.66 | 0.10 |
| Wild rice, cooked (125mL/87g) | 3.46 | 0.15 |
| Oats, large flakes, cooked (125mL/123g) | 3.5 | 0.11 |
| Quinoa, cooked (125mL/98g) | 4.3 | 0.23 |
| Couscous, cooked (125mL/83g) | 3.14 | 0.06 |
| Whole grain bread, commercial (1 slice) | 3.62 | 0.1* |
| White bread (1 slice) | 3.29 | 0.1* |
| Whole wheat pasta, cooked (125mL/74g) | 3.94 | 0.09 |
| White/regular pasta, enriched, cooked (125mL/74g) | 4.29 | 0.10 |
| Corn, yellow, frozen and cooked (125mL) | 2.22 | 0.13 |
| Buckwheat groats, cooked (125mL/89g) | 3.00 | 0.15 |
| Barley, pearl, cooked (125mL/83g) | 1.87 | 0.07 |
| Vital wheat gluten (20g) | 15.03 | 0.4* |
*data pulled from NCCDB database (U.S. data) and is only provided to one decimal place.
Please note: while whole flaxseeds appear to have more protein and lysine, whole flaxseeds are largely undigested therefore the majority of that protein will not be absorbed. Flaxseeds need to be ground for humans to extract their nutrition!
Summary: Protein and Amino Acids for Vegans
Protein is an essential part of a healthy diet. It is possible to get adequate protein and amino acids on a plant-based diet. It is generally recommended for a healthy adult to aim for a minimum of 0.8g/kg of protein; 1.0-1.2g/kg may be a more appropriate target.
Make sure you eat a variety of plant-based sources of protein, and include some higher lysine foods into your day. There are countless options for plant-based meals that are high in protein; get into the kitchen and start cooking!
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References Cited:
- Dietary reference intakes
- Protein balance studies
- Evidence that protein requirements have been significantly underestimated.
- Lysine Requirement through the Human Life Cycle
- Canadian Nutrient File
- Protein and Amino Acids
Please note that this is a curated list of references for the topics above and is not intended to be comprehensive.
Disclaimer: always speak with a doctor before changing your diet. Please read our full website disclaimer.