Introduction to proteins as macronutrient

A short introduction about proteins, composition chemistry and protein content of different foods.

All the proteins are polypeptides, composed of different amounts of amino-acids. We have 20 different amino-acids in their composition, of which 9 are essential and they need to be provided in the diet. The other 11 non-essential ones can be synthesized by our body using the essential ones. The amino-acids are linked through peptide bonds. If there have two, they are called dipeptide, if they have three, tripeptide and so on. The complex proteins have hundred, even thousands of peptide bonds. In each food we have different proteins in different quantities. The amino-acid has a acid group (carboxyl) and an amino group. Depending on the structure, they can be hydrophilic (water loving) or hydrophobic (fat loving).

Let's see some foods and their protein content:

Peanuts 25.5%
Cheese 24.5%
Pork chops 20.4%
Chicken breast 22.8%
Steak 23.8%
Salmon 20.2%
Wheat 12.4%
Bacon 15.2%
Cod 16.4 %
Eggs 12.5%
Milk 3.5%

Protein content of a real food never exceeds 25-30%. There are protein powders used for bodybuilding, containing protein up to 90%, but after they are diluted with milk, water or juice, they will have on average 20% protein content.

Adult vegans can get their protein from soy, nuts, beans and grains, but young children need dairies at least,and maybe eggs,  because while the vegan diet is possible, it is not recommended for children, as very often the parents need solid knowledge related to the mater.

Next post will be about the protein absorption and digestion. See you soon.