Plant protein vs animal protein. Today more and more people are approaching a vegetarian or vegan diet to eat less meat, and on the other hand omnivores are eating more and more meat, cheeses, and less fish and legumes. But at the nutritional level, are animal and plant proteins the same? Which would you prefer ? Let’s find them out together!


What are proteins and what are they for?

Proteins are macromolecules that perform fundamental functions within our organism. They have a plastic and functional role as they allow the growth and repair of tissues and cellular structures, are involved in muscle contraction, in immune response, in blood clotting and can act as receptors, hormones, antibodies and transporters.

Proteins are molecules made up of basic units called amino acids, that our organism uses for different functions, among which, the most important is the structural one, aimed at building cells.
At any age, there is a need to synthesize new cells every day, because during the entire course of life, most of our tissues are constantly renewed and the organism works continuously to replace the eliminated cells.

The presence of proteins is critical to the health. It is all about not introducing too many of them compared to the actual needs, because their excess can be more harmful than the abuse of fats and sugars. Every day proteins are subject to a continuous turnover, a demolition and synthesis process that determines a loss of proteins that amounts to 20-80 g per day. It is therefore obvious that it is important to provide the body with a daily amount of protein to restore this loss.

What are animal proteins?

Animal proteins, as the name suggests, are contained in food of animal origin (meat, fish, eggs, milk, cheese and dairy products). As mentioned above, proteins are made up of amino acids and some of them are called essential, because the body is not able to produce them and it is essential to take them with the diet.  As for all proteins, those animals are formed by the concatenation of about twenty amino acids, 8-9 of which are essential; the organism, in fact, is not able to synthesize these amino acids and consequently, they must be introduced regularly with food.

Animal proteins are called noble or complete, because they contain all the essential amino acids in balanced quantities. Animal proteins have the disadvantage of being present in foods where there is also the presence of saturated fats and cholesterol, harmful to the health of the arteries. The only exception is fish: fish products contain proteins with polyunsaturated fats and very little cholesterol.

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What are plant proteins?

Plant proteins are contained in foods of plant origin: cereals, legumes, seeds, algae, fruits and vegetables. Plant proteins are called incomplete because they are deficient in one or more essential amino acids. They are present in cereals and derivatives, legumes, oily fruits. They have the advantage of being in foods that do not contain saturated fat or cholesterol, and they are also sources of dietary fibres.

Regarding digestibility, plant proteins have a lower digestibility (this applies especially to cereals). The digestibility coefficient, a parameter that indicates the percentage of food that is absorbed, is definitely higher in meat and eggs, while it is lower in legumes. Foods containing vegetable proteins, being a good source of fibres, have a high satiating power and are low in calories, but are often deficient in iron and vitamin B12.


Which proteins to choose?

It is clear that at the nutritional level the amount of protein is not the only parameter to consider. It is necessary to consider the protein quality in terms of amino acid composition. The deficiency of essential amino acids in plant proteins can be overcome by combining vegetable foods of different origin.

The combination of pasta and legumes, such as pasta and chickpeas, is an excellent combination of protein complementarity, since the amino acids whose pasta is deficient are supplied by chickpeas and vice versa. In particular, pasta is deficient in lysine that is present in the chickpeas, while in the chickpeas is present the methionine that is deficient in pasta. These are important essential amino acids, since lysine deficiency can lead to a deficiency of vitamin B3 (niacin), which is essential for the functioning of the nervous system and for cellular respiration; while methionine is important for hair growth, nails and for the synthesis of glutathione, a powerful antioxidant that is able to protect our cells from oxidative stress.

Therefore, by associating two proteins of rather low biological value, we reach an appreciable composition of essential amino acids, comparable to that of meat and fish.
Animal proteins are not to be preferred to plant ones because they have a high acidifying power, and if on the one hand it is true that our organism fights acidosis through buffer systems, on the other, in the long run, the same systems can result in a decalcification of bones. In addition, foods containing animal proteins are rich in saturated fat, cholesterol and deficient in vitamins and minerals.


A varied and balanced diet is the best strategy to meet the daily needs of certain nutrients, whose deficiency can induce or encourage the development of diseases. The advice is to continuously vary the source of protein taken. At the same time, it will also be important to alternate the various types of food.

In case you decide to follow a very restrictive diet such as the vegan one, it becomes essential to be followed by a professional that is able to formulate a balanced nutritional plan, including any useful dietary supplements to make up for deficiencies of macro or micronutrients helpful for good health.