The Protein Fact File
Adequate consumption of dietary protein is critical for the growth, repair and maintenance of optimal health during normal growth and ageing. Amino acids are the building blocks of protein and there are 20 different amino acids of which 9 are ‘essential’ meaning they cannot be produced by the body and must be supplied by the food we eat.
Why is protein important?
Proteins are important structural and functional components needed for a wide range of biological processes. For example, protein is important to build and maintain bones and muscles. It is also involved in the production of enzymes, hormones and antibodies. Furthermore, protein is specifically involved in muscle protein synthesis as well as the repair of damaged skin, nail and hair cells.
How much protein should we consume?
Requirement for protein consumption depends on several factors such as age and health status. The basic daily recommendation for protein intake in healthy adults is 0.80 to 0.83g per kilogram of body weight. This means that an adult weighing 70kg would require approximately 56-58g of protein/day. In fact, this recommendation can be easily met and in the UK the average daily intake of protein is around 88g for men and 64g for women. The daily recommendations are highest during the first years of life due to the rapid increase in growth and also vary for pregnant/breastfeeding women.
Consuming a variety of meat-based and plant-based proteins will ensure that you meet the daily requirement however the amount of protein that you need will vary based on your body weight and activity level. For example, if you exercise for more than an hour a day or if you are an athlete, your protein recommendation increases up to 1.2 to 1.4 grams per bodyweight.
What are the main sources of protein?
Some examples of animal-based protein include meat, fish, eggs and dairy products. For example, a 100g chicken breast and Greek yoghurt contain approximately 32g and 10.3g of protein, respectively. It is important to note that animal-based protein can also be high in saturated fat and salt which can increase the risk of developing cardiovascular disease. Therefore it is important to choose lower fat protein-rich foods such as lean meats and reduced fat dairy products.
Plant-based protein sources include nuts, seeds, beans, legumes and unrefined grains. Food sources derived from soybean contain high protein content, where 100g of soya chunks contain as much as 50g of protein.
Do we need to take protein supplements if we are vegan or vegetarian?
Protein from animal origin are shown to be ‘high quality’, meaning that they contain all the essential amino acids. However, although the plant protein sources may not be as complete
as the animal-derived ones, some plant sources such as soybean, tofu and legumes contain equally as high protein content. Nevertheless, it is important to understand the concept of ‘complementary action of proteins’. This means that different proteins complement each other when consumed together in a meal where the amino acids of one food protein may compensate for the lack of amino acids in another. This highlights the importance for vegetarians and vegans to consume a variety of proteins such as legumes, nuts, seeds and unrefined grains to ensure adequate intake of quality protein without the need of additional protein supplementations.
Take home message
Consuming adequate amounts of protein is essential for a healthy diet but it’s not all about eating meat products. Emerging nutritional research puts great emphasis on plant-based protein sources but this shouldn’t mean avoiding meat and dairy entirely. Rather, it is highlighting the importance of consuming a varied diet. If your goal is to eat less animal protein, focus on slowly easing into meatless meals by replacing meat products with plant-based proteins or by going meat-free one day a week. Remember, complete exclusion of any food is not necessary to follow a healthy lifestyle. It's advisable to speak to a registered nutritionist or dietitian should you require personalised support and guidance.
By Mary Gracia Arulpragasam. Gracia is a Registered Associate Nutritionist (ANutr) who works as a Childhood Obesity Assistant within the NHS School Health Services. She provides public health focused service to children, young people and families in Lewisham. She also runs an evidence-based nutrition page on @nutrition_marygracia