Protein is a macronutrient that provides four calories per gram. Along with carbohydrates and fats, protein is one of our primary sources of energy. The body also uses protein to perform the following functions: Tissue development, including muscle, bone, and skin.
What exactly are proteins?
Proteins are large organic molecules formed by long chains of chemical compounds called amino acids.
The amino acids can be combined in any order and repeated in any way. If we take into account that an average protein is made up of between 100 and 200 amino acids, the number of possible resulting combinations is enormous.
On the other hand, human proteins are made up of 20 amino acids, of which 8 are essential. Our body cannot form the latter by itself, so it is necessary to obtain them daily through food.
How do they work?
Each animal or plant species is formed by its own type of proteins, incompatible with those of other species.
This translates into an inability for our organism to directly assimilate the proteins it obtains from food.
To be able to absorb and use them, it is necessary that during digestion, and by the hand of various enzymes and gastric juices, previously break them down into its simplest components, amino acids.
Once this is done, these basic elements pass into the blood and are distributed throughout the tissues. It is there that they combine with other amino acids from proteins that have been degraded and form new ones, of one type or another according to the needs of the moment.
What are they for?
Without them, our muscles would not exist. However, this is only one of the many important tasks they perform.
If we take into account that the term protein comes from the Greek proteios that means primary, the oldest, the first, we can already get an idea of the great relevance they have for our organism.
It could be said that they serve almost everything, since they are present in most of the vital functions of the body: they are necessary for the formation and repair of tissues.
In addition to the muscles, they provide the materials that make up the bones, glands, internal organs, as well as the skin, hair and nails.
Muscle contraction, immune protection and nerve impulse transmission depend on them. They delay the aging of the body and can also act as a source of energy when carbohydrates and fats are in short supply.
Where do we find proteins?
Being a constitutive element of every living cell, they are found in all tissues and in almost all foods.
What varies, of course, is its concentration and its nature. According to it, we can establish two major sources of protein: those of animal origin (meat, fish, eggs and dairy) and those of plant origin (cereals, legumes and nuts).
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They’re all the same?
No, there are higher and lower quality. It depends on whether or not the protein contains the essential amino acids and in what proportion.
It is enough that a single amino acid is lacking so that the quality drops sharply, since so that your organism can form its proteins it is necessary that it has each and every one of the essential components.
In addition, the increase of one amino acid does not compensate for the absence of another. For this reason and with some exceptions such as soybeans, animal proteins are considered of better quality than those of plant origin.
In addition to the quality of the protein, you have to take into account if it can be used by your body. Not all the proteins we get through food are digested in the same way.
For example, soybeans, despite having less biological value than other foods of animal origin, have a greater net protein contribution because our digestive system assimilates its proteins better.
Animals or vegetables?
In principle, and with the exception of soy, the fact that animal proteins are of a higher quality than those of plant origin can make us opt for them.
Big mistake. Remember that the former are usually accompanied by fats, mostly saturated, which increases the risk of cardiovascular disease.
In front of them, vegetables contain less toxic substances, less burden the liver and kidneys, are easy to digest and their content of saturated fats and cholesterol is low or zero.
In any case, a balanced diet should include both. Ideally, two thirds of the proteins we consume are of plant origin and one third, animal.
How many do we need?
The amount of protein that each one needs is determined by several factors, such as age, the health of our intestines and our kidneys, etc., elements that, in short, vary the degree of assimilation.
According to the WHO, an adult man needs about 0.8 g per kilo of body weight daily. This figure is much lower than those considered a few years ago; in fact, in the last two decades, the amounts of recommended proteins have been halved.
Athletes who undergo a hard training program need a greater amount of protein than those who lead a sedentary life.
However, the difference between the protein needs of both is not as large as it is customary to believe.
According to different studies, the recommended amount for those who practice aerobic resistance sports is between 1.2 and 1.4 grams per kilo and day, and increases slightly for those who have an extreme energy expenditure, such as marathoners.
These amounts are covered with a balanced diet without resorting to nutritional supplements. Usually, an athlete needs a greater number of calories, so he eats more. That increase is more than enough to provide extra protein needs.
Lack of protein
* When the body does not receive the proteins it needs daily, it searches for them in its own tissues, which causes a loss of muscle mass.
* You get tired before, physically and mentally.
* The immune system suffers and you are more vulnerable to infections.
* The ability to eliminate waste products is reduced, in the case of free radicals that cause aging.
* Metabolic processes slow down.
* Excess protein is burned in cells to produce energy. But unlike carbohydrates, their combustion is more complex and produces metabolic wastes, such as ammonia, which are toxic to the body.
* Overload of work to the liver and kidneys, with the risk of problems in both.
* May cause bone decalcification, which ends with osteoporosis.
* The stomach secretes an excessive amount of acid.
* Dehydration may occur due to excessive fluid loss.
* Increases body heat.
* The organism undergoes premature aging.
* It can give rise to various diseases of the liver, arteries and joints, and colon cancer.
* The breath ceases to be precisely fresh and pleasant, and acquires a smell similar to that of ammonia.
* And, in the long term, it causes fatigue and decay.