Protein is an essential nutrient that plays different roles in our body. Without it, we cannot live.
Protein contains about 16% nitrogen, which we need and which can almost only be found in protein. We measure protein by the amount of nitrogen present. The more nitrogen there is in a food, the higher the amount of protein there is.
Our bodies are continuously using protein and it can’t be stored, so we need to put it back into our bodies by consuming food that provides the necessary amino acids that we need for protein synthesis.
Amino Acids
Protein is made up of a chain of amino acids. There are 20 amino acids and they can be classified into three groups:
Essential
Non-essential
Conditionally essential
Amino acids are arranged in a precise sequence in a chain; think of beads on a necklace. Throughout the day our body is losing certain beads from the ‘necklace’ and we need to replace them by eating protein-containing foods.
Protein-combining myth
In the past there was the protein-combining myth that said in order to obtain complete protein from plant foods we had to combine certain combinations of foods, which complimented each other. The amino acids lacking in one food are found in the other and vice versa. Frances Moore Lappé, author of the best-selling 1971 book, ‘Diet for a Small Planet’ wrote that plant foods needed to be combined in order to compensate the missing amino acids. However, that myth has been debunked and ten years later, in the tenth edition of the book, she corrected that statement. We do not need to eat complimenting foods to get all the necessary amino acids, but if you like the combinations, go for it!
A few examples of protein-combining are:
Rice and beans
Barley and lentils
Hummus and pita bread
Peanut butter on wholemeal bread
Cornbread and beans
As long as you are eating enough calories of an assortment of plant-based foods in a day, you shouldn’t have any problem whatsoever getting all the amino acids needed to complete the amino acid chain.
There are a few plant-based foods that actually contain all the essential amino acids and are therefore considered ‘complete’ proteins.
Quinoa
Buckwheat
Amaranth
Hempseed
Chia seed
Tofu (soybean ‘cheese’)
Tempeh (made with fermented soybeans)
Edamame (young soybeans)
Spirulina * (it doesn’t contain all the amino acids, but it’s almost complete)
Let’s not forget though, if you are eating a good selection of plants, you should be covered protein-wise. There's no need to fixate on complete proteins.