Today we hear a lot about this nutrient; of diets rich in protein to lose weight, or to increase muscle mass by supplementing the diet, with products specially formulated for this purpose; This is seen more in the world of athletes.
But what are proteins really? What function do they fulfill in our body? Should we consume them every day? What foods provide protein?
Definition: what are proteins
First of all, you must know what kind of nutrient this is, in order to later be able to define well what they are for. The proteins are substances of very structure complex, based on monomers of nitrogen, better known as amino acids; Currently 20 different amino acids are known that combine with each other to form the different types of proteins. These amino acids can be classified into:
· Essential amino acids: these cannot be synthesized by the body and must be ingested with food or protein supplements.
· Semi-essential amino acids: they are necessary only in certain stages of life or in certain situations.
· Non-essential amino acids: these can be synthesized by the body from essential ones.
It is also important to know that proteins provide 4 calories per gram, that is, a food that has 10 grams of protein, provides 40 calories that come from these. It is recommended that around 15% of the calories that should be consumed in a day, for a healthy person, are provided by protein.
Functions performed in the body
This nutrient fulfills various functions in our body, which is why its daily consumption is essential. The main ones are:
1. Structural function
They constitute cellular structures, are part of cell membranes, are present in muscles, bones, and supporting tissues such as collagen and elastin.
2. Enzyme function
They are part of the enzymes that act by accelerating all metabolic processes in the body.
3. Hormonal function
Many hormones in the body are of protein origin such as insulin and glucagon, which regulate blood sugar levels, also growth hormone secreted by the pituitary gland and calcitonin which regulates calcium metabolism, among others.
4. Regulatory function
There are proteins that participate in the regulation of gene expression and cell division.
5. Homeostatic function
They maintain osmotic balance and, together with other buffer systems, maintain stable body pH.
6. Defensive function
The cells of our immune system, immunoglobulins, mucins, etc. They are made up of proteins and help defend us against bacteria and external agents that could make us sick.
7. Transport function
Substances such as haemoglobin and myoglobin are oxygen carriers in the blood and are made up of proteins. Lipoproteins too and are in charge of transporting cholesterol and other fats in the blood.
8. Energy function
This function is the least relevant of all since carbohydrates and fats are responsible for this; but in special situations of malnutrition due to lack of intake of the latter two, proteins can provide calories but generating an organic weakening due to the consumption of endogenous proteins.
Foods that provide protein
The proteins of high biological value, ie the best quality, found in food source animals: meat (beef, chicken, fish, pork, lamb, etc.) milk and its derivatives such as yogurt and cheese; and the egg. These foods by themselves provide all the essential amino acids.
The vegetables, fruits, grains and legumes also hav