Protein. It’s the popular word of choice in the nutrition and fitness community and there’s a good reason why.

Protein is something that is essential for all humans on this planet and without it, we wouldn’t be alive!

Protein is an essential macronutrient, which is responsible for multiple functions in the body, including building our cells, tissues and organs. Protein is also involved in making our hormones, enzymes and even antibodies. It also helps you to feel fuller for longer, too!

Protein is made up of tiny molecules called amino acids and these are the building blocks of all life.

There are two main categories of amino acids in the body, essential amino acids and non-essential amino acids.

Essential Amino Acids

Essential amino acids are those that our bodies cannot manufacture and so we must obtain these through our diet.

There are 9 essential amino acids, which are:

• Histidine
• Isoleucine
• Methionine
• Leucine
• Lysine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

(Osiecki, 2014) (Semba et al. 2016).

Non-essential Amino Acids

Second, we have non-essential amino acids, which the body typically manufactures by itself. Of the 11 nonessential amino acids, the latter 7 (*) of these are conditionally essential, which means we may require these from the diet in times of stress or illness.

The non-essential amino acids are:

• Alanine
• Asparagine
• Aspartic acid (or aspartate)
• Glutamic acid (or glutamate)
• Serine*
• Arginine*
• Cysteine*
• Glutamine*
• Glycine*
• Proline*
• Tyrosine*

(Hou et al. 2017) (Osiecki, 2014).

What are the best food sources of protein? 

The best way to obtain protein should come from dietary sources first and foremost, before we start to think about supplementation.

1. Eggs – one egg contains approximately 6g protein. I always find eggs great for bumping up my protein intake; they are so versatile and can be cooked in so many ways, giving a varied flavour potential.
2. Fish and seafood – fish is an excellent source of protein, whilst also being a fantastic source of healthy fats. A 100g serving of salmon or mackerel typically provides 20g protein, whilst 100g of herring provides 18g protein.
3. Chicken and poultry – a rich source of lean protein, a 100g chicken breast would typically provide 31g protein.
4. Nuts, seeds and legumes – nuts, beans, and pulses are great ways for vegetarians to meet their protein needs. It is important to consider that plant-based sources of protein are often incomplete proteins, which means that they do not always provide the full spectrum of essential amino acids. Pairing incomplete proteins together is a way to form a complete protein. Complementary proteins include brown rice and kidney beans, or lentils and pumpkin seeds, so pairing these together in any given day will ensure you receive your EAA’s (that’s essential amino acids for those wondering).
5. Dairy – dairy sources (like all other animal proteins) are complete proteins. Greek yoghurt would normally provide 10g protein in a 100g serving, whilst 100g feta cheese packs 14.2g.
6. Tofu – another vegetarian or vegan protein option which provides 4.8g protein in a 28g serving. Fun fact: tofu is a complete protein!

So why should we be eating protein?

Interestingly, the word protein comes from the Greek ‘protos’, meaning first, therefore it must be pretty important! The reason we should be eating protein is because (unlike fat and carbohydrates), it is the only macronutrient that we do not have a reserve of and so we must consume it daily to ensure that we meet our recommended daily requirements.

Once protein is eaten, rather than being stored as protein in the body, it is used to build new cells and tissues, including building and repairing muscle tissue, creating skin cells, enzymes, antibodies and helping to build neurotransmitters.

How much protein should I be eating each day?

According to the BNF, the typical daily requirement for protein is 0.75 grams per kilogram of bodyweight in adults (British Nutrition Foundation, 2017). So if you weigh 58kg, for example, multiply this by 0.75 to find out how many grams of protein you need each day. In this instance, its 43.5g of protein required daily.

However, protein demand increases if you lead an active lifestyle (Friedman et al. 1989). Most professionals advise between 1.3-1.8g protein per kg of bodyweight in those who heavily exercise, especially for those who do endurance or strength training (Phillips et al. 2011). The logic behind this is because when we exercise, we cause micro-tears in our muscles. Protein is essential in building and repairing our muscle tissue and can contribute to exercise recovery (Phillips et al. 2011).

The ‘take-home’

When it comes to protein, there is a lot to learn! Always choose food as your primary source before considering a supplement. Remember that quality is key, so ensuring that you reap the whole spectrum of EAA’s through complete or complementary protein sources is vital in getting everything that your body needs day to day.

Any questions please happily comment below!

 

References:

British Nutrition Foundation. (2017). Protein. Available at: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html?limit=1&start=2 (Accessed: 7 September 2019).

Friedman, J.E. and Lemon, P.W. (1989). ‘Effect of Chronic Endurance Exercise on Retention of Dietary Protein’, International Journal of Sports Medicine, 10 (2), pp. 118-123 NCBI [Online]. Available at: https://www.ncbi.nlm.nih.gov/pubmed/2722324 (Accessed: 7 September 2019).

Hou, Y and Wu, G. (2017). ‘Nutritionally Nonessential Amino Acids: A Misnomer in Nutritional Sciences’, Advances in Nutrition, 8 (1), pp. 137-139 Advances in Nutrition [Online]. Avaiable at: http://advances.nutrition.org/content/8/1/137.extract (Accessed: 1 September 2019).

Osiecki, H. (2014). The Nutrient Bible. 9^th edn. Australia: Bio Concepts Publishing.

Phillips, S.M and Van Loon, L.J.C. (2011). ‘Dietary Protein for Athletes: From Requirements to Optimum Adaptation’, Journal of Sports Sciences, 29 (1), pp. 29-38 Taylor and Francis [Online]. Available at: http://www.tandfonline.com/doi/pdf/10.1080/02640414.2011.619204?needAccess=true (Accessed: 7 September 2019).