Proteins are linear macromolecules made of elementary units of amino acids that are connected to each other by a peptide bond.
There are 20 types of amino acids that contribute to the formation of the protein structure, 8 of which are essential or are substances that the body is unable to synthesize and have to be integrated with food.
Every protein is different from another according to 4 structures (primary, secondary, tertiary, and quaternary) and every amino acid sequence is associated with a specific function.
Functions of proteins
Proteins can have mainly three functions: dynamic, structural, and energetic.
The dynamic function is done by:
- Proteins, called enzymes, which have a catalytic function in metabolic reactions.
- Proteins, like ribosomes, that have the function of translating the information from DNA.
- Proteins, for example myoglobin or carnitine, that have a transport function.
- Proteins, called immunoglobins, with an immune function.
- Proteins, for example insulin, with a function of response to stimuli as well as function as a means of cellular communication.
The structural function is instead due to contractile and muscle proteins, such as myosin and actin, which are the main constituents of the muscular system, and to connective proteins such as collagen, elastin and keratin.
The energetic function is often the most known. The proteins can have an anabolic function, in the case of growth of the body or a catabolic function: in this last case the proteins are destroyed to create energy. The protein catabolism can occur both in the dietary proteins and in the structural proteins themselves, to allow the body to always have the amino acids that it needs.
The class of proteins covers a large number of functions and represents important compounds that, in every diet, are the first to be considered when estimating the calorie requirement: the diet should be made of 25-30% protein and the average daily intake of protein should be around 0,8/1,2 g of proteins per kg of body weight, a value that can quickly grow (up to 2,2 or more) for those who practice sports.
The function of food proteins
The main function of food proteins is connected to anabolic processes.
The main protein food sources are: meat, fish, milk and derivatives, eggs and legumes, but it’s also important to mention food supplements that can be a valid help to reach the daily protein requirement, for example, protein powder.
Whether you’re dealing with protein powder or foods, the capacity of a protein to explicate its functions is given by its quality as a factor it results of:
- Biological value (BV), or the presence of essential amino acids
- Digestibility, or the capacity with which the body digests the protein
Proteins of animal origin (especially those from milk or eggs) tend to be qualitatively better with respect to plant-based ones since they are complete with all amino acids. Nonetheless, they also often represent sources full of saturated fats for which it’s not recommended to eat too much of them and you should favor, instead, an integration of plant-based protein. In order to reach good quality levels of plant-based proteins, this requires functional combinations such as that with cereals like rice and peas and chickpeas and seitan, rice and lentils, they should be complete meals, healthy and nutritious.
A hectic life, with little free time, long work days, as well as the choice of some dietary lifestyles (vegetarian or vegan) could make it more difficult to integrate an adequate protein intake.
Protein powders can be a valuable aid to meet individual requirements.
These are food supplements, or sources of concentrated nutrients, in this case proteins, that can contain a wide variety of substances that are helpful to favor the goal of every person (enriched with rapidly absorbing carbohydrates to speed up anabolism or caffeine, or carnitine to stimulate concentration or lipolysis, or minerals to replenish their loss after and during exercise).
These products are obtained through industrial processes such as filtration, freeze-drying or dehydration of the starting food matrices, so we can obtain:
- Protein from meat: low in fat and sugar, they’re also a good source of creatine and carnitine
- Protein from eggs: very high biological value, rich in antioxidant and bioprotective compounds, they are also known to promote a longer sense of satiety
- Plant–based proteins: rice, hemp, wheat, soy are complete proteins, adept for those who follow a vegetarian or vegan lifestyle or also for those who want an alternative to meat products attempting to reduce their consumption
- Proteins from milk: also known as “whey proteins” are obtained by concentration, filtration and dehydration of the whey. Whey is a constituent of milk (20%) and is the main by-product of the dairy industry that is difficult to dispose of: obtaining food supplements from this source represents an efficient way to recover it and value it, reducing the environmental impact. This class of proteins has a super high nutritional value, a rapid absorption, are very versatile, and thanks to their nutritional characteristics, many studies confirm the efficiency of this integration in the protein synthesis especially when the consumption is combined with a targeted physical exercise. By virtue of their peculiarity, they are the most preferred supplement by athletes, but their benefits have been shown to be useful also for the health of the elderly and those who need a protein implementation.
Obtained from whey, they can be available in various formats including:
- Concentrated Whey Proteins: contain up to 80% protein and 10% fat.
- Whey Protein Isolate: free of fats, carbohydrates, and lactose, they can be up to 90% protein and can be used for example in smoothies, also to help prolong the sense of satiety.
- Hydrolyzed Whey Proteins: like the previous ones, they can reach up to 90% protein content and they differ from the previous ones for their rapid absorption that maximizes muscle recovery.
This class of supplements has always been the favored one, especially among athletes because it results as the best for processes of protein synthesis, anabolism and recovery.
Whey proteins naturally have a low content of fats and carbohydrates, have a very high biological protein value and are rich with essential amino acids that also contain a good quantity of branched chain amino acids, the famous BCAA that, by virtue of their structure, quickly enter into circulation, promoting muscle recovery. The benefits of Whey proteins also go beyond mere protein supplementation:
- The abundance of essential amino acids, leader of muscle growth, is fundamental for all individuals – athletes or not.
- An intake of 25% of BCAA (essential amino acids) and a high concentration of leucine (starting point of the protein synthesis), maximizing the anabolic window and muscle recovery.
- The composition of amino acids of whey protein is very similar to that of skeletal muscle, providing nearly all of the amino acids in approximate proportion to their ratios in muscle.
- The contribution of glutamine, a very important element to combat oxidative stress stimulated by training.
- The whey also contains lactoferrin and lactoferricin, compounds with an antioxidant function capable of binding iron
- The abundance of cysteine in proteins promoted the synthesis of glutathione, a very important antioxidant system
- Lastly, it was noted that the whey, practically lactose-free, contributes to the balance and wellbeing of the gastrointestinal tract.
In addition to all of these benefits, whey protein is characterized by its versatility of consumption: they can be inserted in any moment of the day maybe at breakfast, dissolved in milk or yogurt, as a substitute meal, to make a delicious snack in the form of a milk shake (given that it’s possible to find many flavors) or as a snack pre bed time to prevent nocturnal protein catabolism or again, to prepare fit, sweety or savory recipes.
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