What is protein complementation?

Amino acids are often known as the building blocks of protein and each one performs a number of functions ranging from supporting muscle protein synthesis, to improving your sleep, hormone production and bolstering your immune system. Making sure that you’re getting enough amino acids means actively ensuring that you’re getting enough protein, and for us plant-based people, that might mean doing something called protein complementation.

What is protein complementation, I hear you ask! Well, that’s what this article is all about, so let’s get straight into it - I promise I’ll keep it simple, as it’s a pretty straightforward concept.

What is protein complementation?

First things first, there are two different kinds of proteins: complete and incomplete. Complete proteins contain viable quantities of all nine of the essential amino acids which the body has to obtain from diet, and incomplete proteins, well, don’t. Incomplete proteins aren’t missing anything, they just do not contain a high enough level of one or more essential amino acids for the body to use. 

Many plant-based protein options are not considered to be complete proteins, and this is where the theory of protein complementation comes in. Each plant we eat has a different amino acid profile. There are some amino acids, also known as ‘limiting amino acids’, which are found in the shortest supply from incomplete proteins - they are tryptophan, threonine, lysine and methionine. Whilst being labelled an incomplete protein doesn’t mean that whatever you’re eating isn’t a good source of protein, striking the balance of essential amino acids is important for making sure that you’re getting enough of each. 

Therefore, by pairing protein sources which have different levels of the nine essential amino acids, we can use the amino acid profiles in our foods to build a complete profile of essential amino acids. This active practice of pairing different plant-based protein sources in order to get a healthy balance of all nine essential amino acids, almost like concocting your very own blend of complete protein, is called protein complementation. 

Legumes and veggies tend to be low in methionine and cysteine, whilst grains, nuts and seeds tend to be low in lysine. Therefore, a diet which provides too little of either food group might result in us getting an insufficient amount of certain essential amino acids. 

Grains and cereals are extremely low in lysine, so having these as your only protein sources will not get you any lysine at all, and that wouldn’t be too good. Lysine is pivotal in the production of collagen and elastin in our skin, muscle protein synthesis and regulating our immune function. If that wasn’t enough, it also increases our body’s ability to absorb calcium, and is used in creating our hormones and enzymes. 

Therefore, in addition to your grains and cereals, you can use legumes such as peanuts, dry beans and lentils to increase your lysine intake. Conversely, legumes are often short on tryptophan, which regulates the levels of nitrogen in your body and plays a vital role in the creation of serotonin, making it a very important amino acid indeed. Oats, nuts and seeds can provide the tryptophan you might be lacking from legumes.

How do I do it?

It is suggested that protein complementation is one of the most efficient ways to get all nine of the essential amino acids into a plant-based diet. Let’s look at some of the ways in which you can pair protein sources for an optimal outcome. 

First off - if you have a healthy diet, eat enough calories, exercise regularly and take any supplements you might need, there is no need for protein complementation to be at the front of your mind, and it’s likely that you’re already doing it without knowing you are. Paying attention to what you’re eating in terms of protein is the real key to protein complementation. If you’re eating a varied diet which contains a number of protein sources, then you’re likely to be eating complementary proteins throughout the day. Winner! 

Plus, protein complementation doesn’t all have to be done in the same meal, so if you’re like me and constantly thinking about what you’re going to have for your next meal - or if you’re sensible and batch cook things, you can work out how to vary your complementary proteins in advance. 

For example, rice is really low in lysine, whilst black beans are high in lysine, so mixing black beans in with your rice is protein complementation! Or what about pita bread and houmous - pita bread is low in lysine, but chickpeas, which are the main ingredient in houmous, is full of them! 

So there you go, it really is as simple as adding a handful of frozen peas to your pasta sauce or having whole wheat toast topped with peanut butter for breakfast (or lunch, or just a snack, really. I love peanut butter).

See what I mean about how you’re likely to already be complementing proteins without knowing it? Plus, if you’re doing lots of exercise and want to be certain you’re getting enough of the essentials, Vivo Life’s intra-workout complex SUSTAIN contains all nine essential amino acids, and our entire protein powder range is blended from different sources of plant-based protein sources to aid in protein complementation throughout the day!