• Protein builds Muscles, but how does it work?
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Protein builds Muscles, but how does it work?

Everyone associates protein with muscle growth. If only it was as quick to work as the old cartoon popeye used to demonstrate. The sailor cartoon used to down a can of spinach(?) and immediately developed huge biceps and all round muscle! As we cannot rely on that kind if magic, we wanted to talk about the science behind muscle. In particular, the connection between eating protein or drinking protein shakes and your muscle growth. So here it goes..

Skeletal muscle is made up of 70% water (always stay hydrated!), 23% protein and 7% minerals (calcium, potassium, phosphorus) & other substances (glycogen, glucose & fatty acids). We're going to talk about protein today but just a point on those minerals - it helps to obtain a balanced diet so all the vital elements come together. For example, we often recommend that protein shakes could be mixed with whole milk for the calcium and fatty acids. 

Proteins form part of every living cell providing physiological functions (hormones like insulin are proteins), providing energy and of course, structure to our bodies through the growth and repair of tissue like muscle.

When we work out or exercise, we break/damage some of our muscle fibres. Don't worry though, this is not injury related but totally natural and has to happen for them to be rebuilt stronger. If you think about it, our bodies are constantly undergoing repair e.g. our skin cells shed all the time and new ones are created.

A cellular process takes place in each muscle which are made up of what's called myofibril strands. They are repaired and fused together to form new myofibril strands. The new myofibril protein strands grow back thicker and in greater numbers which creates muscle growth (sometimes called hypertrophy). 

There are two distinct types of muscle fibre - 1) 'Slow Twitch Type 1' which are smaller and have a higher oxygen delivery but provide less force. They are used mainly for maintaining our posture and endurance activities, and 2) 'Fast Twitch Type 2' which are larger and have a decreased oxygen delivery but provide more force for rapid, intense movements.

Most muscles are actually a mixture of the two types of fibre however there are some differences. The neck and back are mainly slow twitch to help with posture. Our shoulders and arms need to generate a lot more force so are made up mainly of fast twitch fibres. Marathon runners therefore tend to have 80% slow twitch fibres whereas sprinters have 60% fast twitch. Weight-lifters have an equal mix of slow and fast. Unfortunately, this mix is genetically controlled but eating the right thing and training can make an impact. 

Muscle fibres are built up over time and by a combination of exercise and the correct fuel. 

The protein we eat (or drink in the case of protein shakes) is digested as a result of enzymes which break down the nutrients into soluble-sized molecules ready for absorption by the body. In the case of protein, the enzyme protease is produced which breaks down the protein into amino acids in the stomach and small intestine. A network of blood capillaries then transport the amino acids away from the small intestine to the cells of the body.

There are 20 long-chain amino acids, 12 of which are what's called 'non-essential' and come from non-animal sources (plants). The remaining 8 amino acids are called 'essential' or 'EAAs' and come from animal sources. They are called essential because the body cannot synthesise them from other compounds so we need to get EAAs into our diet in order to obtain them.

Of the EAAs, are 3 branched chain amino acids (BCAAs) which you may have heard of as having the biggest impact on muscle growth & repair. They account for 33% of muscle tissue! It's important therefore to ensure you are eating as many complete proteins are possible within your diet but also a high level of BCAAs for optimum muscle repair. Full details of the names of the amino acids can be found on a previous blog we wrote on BCAAs.

It is generally advised that we try and eat high quality protein from a variety of sources and try to go for these 'complete proteins' where all 8 EAAs are present. Examples are meat, fish, poultry, dairy and eggs.

You can however eat 'incomplete proteins' (which do not have all 8) from plant sources such as pulses, grains etc. The important thing with these is that each type of plant source are normally missing 1 or 2 EAAs (hence incomplete) so try combining plant protein sources to solve the problem. E.g. combinations of cereal/rice with pulses such as peas or beans or nuts can usually supply adequate amounts of required amino acid for a complete profile. Our organic protein is a complete protein and contains 6g BCAAs per 35g serving.

So in summary,

  • Protein is part of every living cell, not just muscles so an important and major nutrient as part of a balanced diet.
  • Muscles are made up of 23% protein and rely on it and other substances to rebuild and repair after exercise.
  • Ingesting protein involves breaking it down in amino acids which are split into non-essential and essential. We should try and eat a variety of protein to ensure we are obtaining a good mix and particularly EAAs which we can only get through our diets and of which BCAAs are important for muscle growth.
  • Muscles are developed over time through a combination of training and good, balanced nutrition.

We hope you've learnt something useful and good luck sourcing the best ingredients to help your muscles get leaner and stronger over time.

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