What is Protein? - A mixture of amino acids. It is the order and amount of these amino acids that make up the different proteins
The Science Bit - Structure of Protein
The building blocks of amino acids, they look a bit like this:
It is the Nitrogen molecule that makes the protein unique, compare with the other macronutrients. This is what is use for it's repair and building functions. Protein can also be use as an energy source by stripping off the nitrogen source.
The body can build most Amino acids by changing the amino group, but the essential one cannot be synthesised by the body and MUST be found in the diet.
By adding 2 amino acids together you get a di-peptide bond. To form a protein many many amino acids must be formed in a long chain. To joining these 2 amino acids together you end up removing a molecule of water. See diagram below.
This is what is then looks like:
If this process is repeated and repeated you eventually get a polypeptide chain and a fully-fledged protein structure
To get into out bloodstream this protein must be must be broken down into single amino acids. To do this we need to add water! There are many many chains to break down here all of which require water, so another good reason to drink lots of water! This breakdown also requires certain key enzymes.
How much Protein should we eat?
About 1g of protein per 1 kg of body weight should be sufficient. In the UK we tend to eat far too much protein. This equates to about 10 - 15 % of your total calorific intake for the day.
But increased training, physical or mental stress can increase an individuals protein requirement.
Where do I find good sources of Protein?
There are 2 different sources, animal and vegetable. Animal sources are form meat, fish, milk and cheese and tend to be high in saturated fat. Animal protein is a complete source of amino acids, i.e. they are high in the essential amino acids.
Vegetable sources are usually beans, lentils, TVP, and quorn, as well as bread, pasta and rice, but these are incomplete as they do not contain all the essential amino acids, so a vegetarian must ensure that they eat across the vegetable protein sources to make sure they get a complete range, i.e. peanut butter sandwich or beans on toast.
Examples of proteins sources:
Lean beef - 32g per 4oz
Chicken breast - 35g per 6oz
Tuna - 40g per 6oz
Tofu - 11g per 3.5oz
Eggs - 6g per large egg
Cheddar - 7g per 1oz
Yoghurt - 11g per 8oz
Lentils - 15g per 8oz
Pasta - 4g per 8oz
What happens if I don't get enough Protein?
· Low energy
· Low stamina
· Poor resistance to infection
· Mental depression
· Slow healing of wounds
· Prolonged recovery from illness
What happens if I get too much Protein?
· Strain on liver and kidneys