For someone new to a plant-based or vegan lifestyle, the topic of complete proteins vs incomplete proteins can seem confusing. The need to combine vegan proteins to create a complete protein can make a vegan lifestyle seem that much more challenging. But where did the concept of protein combining come from and how are complete vs incomplete vegan proteins defined? Is it even necessary to combine proteins when following a vegan diet?
Read on to learn:
- What is a complete vegan protein?
- What is protein combining?
- Is protein combining necessary on a vegan diet?
- How to get complete vegan protein
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What is a Complete Vegan Protein?
Humans need to consume adequate amounts of protein to stay healthy; however, it’s not the actual protein that we need.
Proteins are made up of smaller molecules called amino acids and it’s these amino acids that the body requires. There are 9 essential amino acids that must be consumed.
When people talk about complete protein sources, they typically refer to one food that contains an ideal amount of all 9 of these essential amino acids. When referring to a complete vegan protein, it means a plant-based source of protein that contains adequate amounts of all 9 essential amino acids.
There are several methods to determine whether a protein is considered complete or not.
How Did Science Decide What a Complete Protein Is?
There are a few methods used to determine the quality of a protein source 1. Quality proteins are typically defined as those that provide adequate amounts of all 9 essential amino acids (a “complete” protein).
There are flaws to all the methods that determine what a quality/ complete protein is 1. However, the data available generally concludes that certain foods provide complete proteins (a good amount of all 9 essential amino acids) whereas others do not.
Generally speaking, animal products and some plant-based foods contain enough of all the essential amino acids. However, most plant-based foods are found to be lower in at least one essential amino acid.
Legumes are lower in the amino acid methionine, whereas most other plant-based sources of protein are found to be lower in lysine 2. Keep in mind that all whole plant foods contain all 9 essential amino acids, it’s just that one or two amino acids are lower in certain foods 2, 3.
What is Protein Combining?
Protein combining builds off the idea that certain sources of protein do not contain adequate amounts of all 9 essential amino acids. If one food cannot provide enough, the thought is that combining two or more sources of protein together will create a balanced amount of essential amino acids.
Basically, protein combining means you take two “incomplete” sources of protein, consume them together and in this way you have created a complete protein.
For example, since whole grains are low in lysine, but legumes have a higher amount of lysine, combining a whole grain with a legume should provide enough of all the needed amino acids.
Is Protein Combining Necessary on a Vegan Diet?
It’s a long-standing recommendation for vegetarians and vegans to combine protein. While there’s little harm to be found from combining multiple plant proteins into one meal, it’s not strictly necessary to combine proteins at every meal 2, 3, 4.
If enough protein and essential amino acids are consumed over the course of the day, there shouldn’t be any concern 2, 3, 4.
What may become a concern for vegan diets is getting enough lysine, but this can be achieved through eating legumes and other high lysine foods 2, 3.
If you want to combine more than one source of protein into one meal, go for it! Whole grains, legumes, nuts and seeds are all staple foods for a healthy plant-based diet. These higher protein foods are a great starting place for creating any meal.
The point is that there’s no need to become overly focused on getting a combination of protein at each meal. Rather aim for a variety of protein sources throughout the day; and if your meals contain several plant-based proteins, great! Getting adequate nutrition on a vegan diet can be complicated enough without having worry about protein combining.
How to Get Complete Vegan Protein
Consuming some higher protein plant foods at each meal is a great way to meet protein (and amino acid) requirements as a vegan. Getting in a variety of higher protein foods, specifically legumes (for lysine) along with whole grains, nuts and seeds can easily meet the protein and essential amino acid needs of a vegan diet. Keep in mind individual needs vary, so some people may need to focus more on consuming adequate protein (speak to a Registered Dietitian if you have any concerns).
It’s generally recommended to include protein at each meal anyways. This not only helps meet protein intake requirements, but higher protein foods can keep you feeling full and satisfied.
Summary: How to Get Complete Vegan Protein
The concept of protein combining to create a complete vegan protein is a myth. If enough of the essential amino acids are consumed throughout a day, protein needs can be met through a vegan diet. However, it’s still important for vegans to meet their protein and amino acid intake requirements. Consuming a few servings of higher lysine foods each day can add up to help meet these daily requirements.
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References cited:
- Protein – Which is Best?
- Protein Part 1—Basics
- Plant Protein: A Vegan Nutrition Primer
- Position of the American Dietetic Association: Vegetarian Diets
Please note that this is a curated list of references for the topics above and is not intended to be comprehensive.
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