Dietary proteins have been a topic of nutrition research for over a century, and proteins as part of a balanced diet are vital for body function and growth. Proteins contribute to muscle mass and to the normal growth and development of bone in children. The sections below cover what protein is, where it is found, and whether protein source matters.
The make-up of protein
The building blocks of proteins are amino acids: the components that give protein its nutritional value. Amino acids underpin healthy cell and organ function (Institute of Medicine, 2002/2005) and are involved in muscle function, growth, and repair. Hundreds of amino acids exist in nature. For humans, around twenty different amino acids form the basis of all body proteins. Nine of these can only be obtained through diet, commonly referred to as the essential amino acids (EAAs).
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Essential amino acids cannot be synthesised by the body. They must be obtained from food |
There are hundreds of amino acids that are found naturally. However, for humans some twenty different types of amino acids form the basis of all proteins in your body. Nine of these amino acids can only be obtained through diet. These are commonly referred to as the essential amino acids (often abbreviated EAA).
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Throughout the day, a constant turnover of protein takes place in the body. Muscle accounts for up to 50% of the entire protein turnover. |
Dietary protein quality
Different food sources contain different amounts and combinations of protein and amino acids. Alongside fats and carbohydrates, proteins are macronutrients required in substantial daily amounts. Unlike fat or carbohydrate, the body does not store excess protein, so regular intake is required.
The diagram above compares whey and plant-based protein sources in terms of dietary protein quality. The two scores measure the protein against the amino acids needed by the human body – Proteins with a score of 1 match daily recommended requirements of essential amino acids. Proteins with a score below 1 do not match daily recommended requirements of essential amino acids.
Required daily protein amount:
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Daily protein needs range between 0.8 and 2 g per kg of body weight, depending on age, health status, and lifestyle. |
A varied diet combining different protein-rich foods makes meeting protein and amino acid requirements straightforward for most people. For those who do not eat a varied diet or who want a quick and reliable way to increase dietary protein without combining sources, dairy-based proteins such as whey provide a high-quality option.
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After water, protein is the most plentiful substance in the body. |
Protein requirements
Required protein intake depends on age, lifestyle, and overall health. There is no single recommendation that applies across all individuals. In general, growing children, physically active people, and pregnant and breastfeeding women have higher protein requirements than sedentary adults. The right amount of protein and personalised estimate should be based on age, weight, height, and activity level.
[1] https://www.healthline.com/nutrition/essential-amino-acids#roles-in-your-body
[2] https://en.wikipedia.org/wiki/Leucine
[3] https://www.nature.com/scitable/topicpage/protein-structure-14122136/
[4] https://www.webmd.com/men/default.htm
[5] https://en.wikipedia.org/wiki/Whey
[6] On www.wheyforliving.wpengine.com we refer to proteins with the DIAAS score 1 or above as complete proteins