Proteins are complex molecules that play a fundamental role in our organism, so much so that they are indispensable for the structure and function of the body and for the regulation of many of its functions.
In the body, proteins perform numerous functions:
- Antibodies of the immune system
- Enzymes that regulate metabolic reactions
- Hormones and messengers
- Structural components such as in muscles and skin
- Transport proteins
Each protein is made up of a collection of smaller units called amino acids which are linked in long chains. There are 20 different amino acids that can make up a protein and the sequence of these determines the structure but also the specific function of the protein itself.
To understand the need for protein requirements, two basic assumptions must be considered:
- Proteins, whose name means “of primary importance” , are substances that arise from the almost infinite combinations of twenty amino acids. Macromolecules – precisely proteins – are derived with highly specific and indispensable functions for the proper functioning of our body such as enzymes, antibodies, hemoglobin, some hormones, to name the best known.Nine of the twenty amino acids are essential , meaning they must be introduced through food because the body needs them and does not obtain them from other food sources. Eight others are defined as conditionally essential , because they play a fundamental role in maintaining organic functions and under certain conditions their synthesis from other food sources is not as rapid and efficient.
- Proteins are subject to a continuous process of demolition and synthesis called protein turnover , expression of the human body’s ability to adapt to changing needs.
The food sources of protein are all foods of animal origin (meat, fish, eggs, milk and derivatives), legumes, nuts and seeds oily , and to a lesser extent cereals. Qualitatively they are distinguished on the basis of the completeness with which they provide the entire range of amino acids – in particular essential and conditionally essential – which is maximum in the case of foods of animal origin, good in the case of legumes, oil seeds and nuts, poor in the case of cereals.
Proteins are therefore of primary importance for the functionality of the body and for this reason it is necessary to take them regularly through nutrition. In fact, proteins are, together with carbohydrates and fats, a macronutrient, that is a category of substances whose contribution must be regular and in the correct doses.
Animal and vegetable proteins
If we limit ourselves to considering the biochemical structure of a protein, there is no difference between protein of animal and vegetable origin. Therefore, those who attribute to animal proteins different effects from plant ones focus on factors that have nothing to do with the proteins themselves but with other substances that may be present in the food. However, there are some important differences:
- Biological value: the biological value defines the extent to which a protein is absorbed from food and incorporated into the body’s proteins. The proteins contained in foods of animal origin have a more complete spectrum of amino acids and therefore have a much higher biological value than those of vegetable origin.
- Overall composition of the food: each food is composed of several macronutrients. Foods of animal origin contain proteins and fats while those of plant origin provide proteins and carbohydrates.The overall action on the body depends on the type of fat (some animal foods have high concentrations of saturated fats, others instead of very healthy omega 3 polyunsaturated fatty acids) and on the metabolic conditions of the person in relation to the amount of carbohydrates consumed during the day (if you consume legumes thinking that they are proteins, keep in mind that they actually provide a lot of carbohydrates).
Read more: animal and vegetable proteins.
How many-proteins to eat per day
Together with carbohydrates and fats, proteins are a fundamental macronutrient that must never be missing from our nutrition. Today we often hear superficially saying that proteins are bad but it is an absurd statement and without any scientific validity.
Proteins must be taken in the correct dosage which is easily determined following the international guidelines:
- Subject inactive (not engaged in any physical activity): 0.8-1 gram per pound of body weight
- Active person or over 60 (who does regular and moderate physical activity): 1-1.2 grams per kilo of body weight
- Subject sports (who trains intensively for sports performance): 1.5-2 grams per pound of body weight (source).
A moderately active subject weighing 70 kg needs about 70 grams of protein per day. In theory, the proteins contained in cereals and other non-protein foods must also be included in the calculation but in fact have a modest impact.
If we consider that 100 grams of meat or fish contain about 20 grams of protein, we can quite easily assess whether we are reaching the necessary quantity . The greater the physical activity performed, the greater the intake of protein to maintain muscle mass.
In some conditions of severe overweight, however, this calculation should not be made on body weight but on the lean mass which can be determined through bioimpedance, a test now easily available in doctors’ surgeries, pharmacies and gyms.
Here is a nutritional table of the foods that we normally include in the diet. Remember that proteins should be distributed during meals and throughout the week, varying the intake according to calorie consumption and physical activity (or work, if sedentary or effort).
|FOOD (100 g)||CALORIES||PROTEIN in g.|
|Chicken (without skin) 100 g||165||31|
|Lentils (half cup)||101||9|
|Red beans (100 g)||333||24|
|Chickpeas (100 g)||364||19|
|Mozzarella (100 g)||280||28|
|Low-fat cow’s milk (100 g)||42||3,4|
|Greek yogurt (100 g)||115||6|
|Roasted peanuts (100 g)||594||25.8|
|Nuts (100 g)||607||20|
|Almonds (100 g)||581||13.7|
|Linseed (100 g)||534||18|
|Soybeans (100 g)||884||0|
|Salami (100 g)||336||22|
|Mortadella (100 g)||311||16|
|Raw ham (100 g)||145||21|
|Cooked ham (100 g)||138||15.7|
|Parmesan cheese (100 g)||392||33|
Benefits of proteins
Taking the right amount of protein per day brings numerous benefits:
- Greater sense of satiety : protein foods satiate more than other categories and therefore the perception of hunger is reduced.
- Thermogenic effect : for every 100 calories of protein food, 25 are spent on metabolizing it, a much greater share than carbohydrates and fats.
- Muscle support : proteins are essential for nourishing muscles and reducing the loss of muscle mass that occurs with aging.
- Immune support : proteins are fundamental components of the immune system and their low intake reduces immune function.
- Mood support : proteins optimize the production of neurotransmitters and their inadequate intake leads to a worsening of mood.
Take protein when doing sports
Protein is particularly important for athletes as it is the essential nourishment for muscles which are essentially made of protein. For this it is necessary that the athlete guarantees an adequate intake of dietary proteins from fish, eggs, poultry and lean meats . The key moment for protein intake is 30-45 minutes immediately after training, when the muscle stores the proteins at their best and starts recovery.
Dietary proteins are absorbed too slowly to provide adequate nourishment to the muscle in such a short time and therefore are of little use in this case. Much better to resort to whey protein isolates which are completely absorbed in a few minutes allowing optimal recovery.
These proteins, contrary to what is often said, are not only useful but also healthy as they contain peptides that have an immunostimulating action.
Read more on protein powder.
Read more on muscle recovery : amino acids and proteins.
amino acids in full or branched form can also be used to support muscle nutrition before or after workouts.
In the first case they replace proteins but hardly bring the necessary grams and also do not have active peptides that act positively on the immune system and therefore do not offer particular advantages.
In the second case the branched ones (composed of leucine, isoleucine and valine) are directed to the muscle, skipping the hepatic passage and are useful for energy purposes.
Don’t stop from learning , only so you can improve your health .
Read the mini supplement guide that can give you a comprehensive overview of more than just protein.