PROTEINS (Amino Acids)

Proteins are another essential need for our bodies to remain healthy. Proteins are broken down into Amino Acids to which are known as the “building blocks” as they help to make more proteins which re needed for growth and repair. Protein can be found in meat, fish, milk, eggs, Soya, beans and milk products. Dietary protein is the main source of nitrogen which can be used in the body. We have over 10,000 different proteins in our bodies which are broken down from protein to,

·        Polypeptides

·        Peptides

·        Amino acids

Amino acids are constantly being used to form enzymes, hormones and cell proteins, so if nitrogen was absent from our diet our bodies would go into negative nitrogen balance. Amino acids are a combination of carbon, hydrogen, oxygen and nitrogen, and contain minerals such as iron, copper, zinc, iodine, sulphur and phosphate. All of the above are divided into two groups “the essential”, and “non essential”, which amounts to 20 altogether. The essential acids must be included in our diets because they cannot be synthesised by our bodies. The non-essential however can be synthesised. Amino acids are used for;

·        Growth / repair of cells / tissues

·        Synthesis of enzymes, plasma proteins, antibodies and some hormones.

·        Provision of energy (needed only when not enough carbohydrates are present)

As already mentioned proteins cannot be stored in the body, so a process called deamination breaks down excess amino acids in the liver, -NH2 (amino group) is removed to form ammonia. Amino acids which are converted to another amino acid is known as transamination. If there is a deficiency in the diet non-essential acids may be synthesized this way. If your liver lost the ability to synthesise proteins you would die within a few days. Amino acids broken down are passed in our urine known as urea. It has a very strong ammonia smell. During exercise our blood becomes acidic as carbon dioxide dissolves in blood. The alkaline group of amino acids act as buffers. This is to act as a cushion which takes the strain and prevents extreme changes of pH in the blood. It also stops the blood getting to much acid in it. Amphoteric means they can be either acidic or alkaline, can act as both.