What are proteins and why are they so important?
Proteins are essential macronutrients that our body needs to function properly. Our body uses proteins as building materials for growth and maintenance, as enzymes, as hormones, as transporters, as antibodies and for many other roles.
Proteins are made up of small molecules called amino acids that are joined together into chains. There are about 20 amino acids that, for humans, fall into two categories: essential and non-essential. Our body can make the 11 non-essential amino acids fairly easily, but we can only get the 9 essential amino acids from the foods we eat.
Any protein that contains the essential 9 amino acids in sufficient amounts is considered a “complete” protein. Plenty of animal products, like meat, eggs and dairy, are complete proteins, but most plant products are “incomplete” because they’ll either be missing some essential amino acids, or they won’t have enough of them. This is the reason people with plant-based diets may need to pay more attention to their protein intake.
So what foods should I be eating?
Although not many plant products are complete proteins, there are a few protein superstars. The oft-mispronounced quinoa (keen-wah) is a complete protein source that’s also packed full of iron, zinc, folate, magnesium, manganese and fibre. A single cup of cooked quinoa is about 8g of protein.
Soy products like tofu and tempeh are also great sources of complete protein. You can experiment with different ways of marinating and cooking them to find a style that works for you.
If you’d rather avoid soy, you can still mix and match foods across the day to ensure that you’re getting all 9 essential amino acids. For example, lots of legumes have high levels of the amino acids lysine and isoleucine, but low levels of the amino acids methionine and tryptophan, whereas grains tend to have the opposite make-up. So, if you wanted to make sure you were getting enough of both, you could try including for example both rice and beans in your diet.
Not every meal you eat needs to have all the essential amino acids, but it’s good to try and make sure you get enough across the day.
In addition to legumes and grains, plenty of other plant-based foods like nuts, seeds and dark leafy greens are full of protein. If you’re eating a varied and well-balanced diet, you should meet your protein needs without too much difficulty. If you’re eating some animal products like dairy or eggs, it’s even easier.
It’s important to keep in mind that, although you should be able to meet your protein requirements on a vegetarian or vegan diet, you also need to pay attention to other key nutrients like iron, vitamin B12, vitamin D, calcium and zinc that are essential for your body’s function.
How hard is it to get enough protein?
Despite concerns about getting enough protein from a plant-based diet, it really isn’t that difficult. If you eat enough of the right foods, these diets are also suitable during all stages of life, even for athletes.
Please be aware that in some situations, like in particular stages of life or if you exercise a lot, you may need more protein to sustain growth, repair tissues and build muscles.
If you need help, a nutritionist or dietitian can help you develop a food plan that ensures you get the amount of protein appropriate for your needs.