There is plenty of talk about dietary protein in a balanced diet. But do you know what dietary protein is and why it is crucial for our body? This article will help you learn more about protein and its role in our everyday lives.
What are proteins?
Proteins are made up of many building blocks – different amino acids linked together.(1) There are twenty different amino acids commonly found in plants and animals, and a typical protein is made up of 300 or more of these, the number and sequence are unique to each protein.(1) These blocks can be arranged in millions of different ways and, depending on the acids’ number and sequence, the protein will fold into a specific shape, which determines its function – for example muscle or enzyme.(1)
These amino acids are classified as either essential, meaning our body cannot produce them on its own and we must get them from our diet, or non-essential, which our body can produce.(1)
Why do we need dietary protein?
The human body is made up of thousands of different proteins with specific functions, making up the structural components of our cells and tissues, enzymes, hormones and more.(1) They are continually being replaced and repaired, throughout our lives. In order to do that, we need a continuous supply of amino acids, which we get through eating dietary protein.(1) There is an increased demand for protein during periods of rapid growth, such as childhood, adolescence, pregnancy and breastfeeding.(2)
How much protein should we eat and which foods contain the most?
Protein can be found in both plant and animal-based foods, for example meat, eggs, cheese, milk, beans, grains and nuts.(3) However, people often wonder if plant and animal-based proteins are of the same quality. Well, the quality of a protein is defined in many ways and they all relate to the distribution and portion of the essential and non-essential amino acids they contain.(1)
From that we can gather that animal-based proteins are of higher quality, as they contain higher portions of essential amino acids than plant-based.(1) Still, most plant-based proteins do contain all 20 amino acids, they just tend to have a limited amount of certain amino acids (known as their limiting amino acids), meaning, if they are our only source of consuming protein (such as is the case with vegan and vegetarian diets), it is likely they will not supply enough essential amino acids for our requirements.(1) The solution is consuming protein from sources with complementary limiting amino acids, in order to get the full scope.(1)
The European Food Safety Authority (EFSA) has developed dietary reference values for protein (DRVs).(2) We have different protein needs at different stages of our lives. For example, an average adult should consume at least 0.83g of protein for every kilogram of body weight per day, or in other words, a 70kg adult should eat at least 58g of protein every day.(2) This is equivalent to the protein found in around 200g of chicken breast, or 240g of mixed nuts.(1) In Europe, we generally do not have problems consuming enough protein and deficiency is rare among most developed countries.(1)
What are the health benefits of protein?
There are quite a few. Among others, eating protein-rich foods has been shown to increase our feeling of satiety, lowers the risk of sarcopenia(4) (a disorder where a person suffers progressive loss of muscle mass and physical function), helps maintain muscle mass and strength as we age and decreases our risk of skeletal disorders.(1) Protein also plays a key role in helping to repair and strengthen muscle tissue after exercise.(1)
Is there such a thing as too much protein?
There is insufficient evidence to establish a threshold for protein intake, and EFSA has stated that a protein intake of twice the DRV is still considered safe under normal conditions in healthy individuals.(2) Excess protein can also be converted into body fat, leading to weight gain.(1) Moreover, it also depends which foods we consume as our source of protein – for example, red and processed meat have been associated with an increased risk of certain cancers.(5) Still, we need not avoid it completely. The World Cancer Research Fund recommends we try to limit our red meat consumption to no more than three portions per week, and very little, if any, processed meat.(5)
Protein is essential for life – our bodies cannot function without it. How much we need depends on our stage and way of life, but most Europeans consume enough to meet their requirements.(1) We should not focus on only consuming enough protein, we should focus on a healthy, balanced and sustainable diet in general, one that will provide us with enough protein, as well as other nutrients needed to keep our bodies healthy and help us face everyday challenges.
- What are proteins and what is their function in the body? Food Facts for Healthy Choices. 2019. Available at: https://www.eufic.org/en/whats-in-food/article/what-are-proteins-and-what-is-their-function-in-the-body
- Scientific Opinion on Dietary Reference Values for protein. European Food Safety Authority. EFSA Journal. 2012; 10(2):2557
- UK food composition database. Available at: https://quadram.ac.uk/UKfoodcomposition/login-register/
- Cruz-Jentoft AJ, Sayer AA. Sarcopenia. The Lancet. 2019; 393 (10191): 2636-2646.
- World Cancer Research Fund/American Institute for Cancer Research. Meat, fish and dairy products and the risk of cancer. Continuous Update Project Expert Report 2018.