What is Protein?
Proteins are composed of 20 standard amino acids – these are chemical compounds with a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom and a unique side chain (the R-group).
Functions of Protein
Contrary to carbohydrates proteins have much more different uses in the body. Their functions include:
1) Speeding up chemical reactions such as digestion;
2) Regulating bodily functions;
3) Signalling;
4) Serving as building blocks of bodily structures such as muscles;
5) And transporting.
Proteins are made through a series of complex processes. It starts from the DNA, which contains instruction manuals, and through complex signalling protein is synthesised in small organs (organelles) called ribosomes in cells.
Proteins can be made up of only a few amino acids bonded together to 27,000 amino acids bonded together (titan, the largest protein in the human body that functions as a molecular spring that is responsible for the passive elasticity of muscle).
Protein intake is essential for growth, repair and maintenance of tissues. Many amino acids can be synthesised by the human body, but 9 amino acids – histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—are not synthesised and are therefore dietarily essential or indispensable nutrients. These are commonly called the essential amino acids.
The recommended dietary allowance for protein is around 0.8 grams per kilogram of body weight in adults, but the recommended amount can be as high as 1g per pound of body weight for those looking to build muscle. Remember this is a general guideline and can vary if you have any medical conditions especially those involving the kidneys
When comparing per mass, protein digestion gives 4 kilocalories per gram which is the same as that of carbohydrate. But because protein digestion is more effortful for the digestive system, the body needs to expend more energy to digest than compared to carbohydrate and fat: although still debated on the exact figures the thermic effect of protein is around 20-30%, carbohydrates 5-10% and fat 0-3%. Protein also is the most and very satiating macronutrient presumably due to hormones released from the gut during digestion such as GIP and GLP-1. It is therefore a good strategy to consume a lot of protein in proportion to achieve weight loss but protein is unfortunately an expensive macronutrient.
Leave a Reply