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Proteins are the basic building blocks of our body. They are responsible for many processes occurring in the body, and their regular supply with food is essential. They are found in both animal and plant products. It's worth noting that proteins and the amino acids they comprise can vary in some parameters depending on their source. Therefore, the question arises as to which sources of this macronutrient are best for the proper functioning of the body. We will attempt to answer this question carefully. However, to better understand the entire topic, we will discuss and characterize individual protein sources.
What are proteins and what functions do they have?
It is estimated that proteins alone make up about 20% of our body weight. That's quite a lot. These macronutrients are characterized by a very complex structure. Proteins of animal origin are composed of 20 amino acids, which can be divided into exogenous and endogenous. The former are also called essential because our bodies cannot produce them on their own. Therefore, they must be regularly supplied with food. These include: lysine, methionine, leucine, isoleucine, threonine, valine, tryptophan, phenylalanine, and histidine. Interestingly, histidine can be produced in our bodies. However, its production in children cannot meet the entire demand. Therefore, it was decided to define it as an exogenous amino acid. However, endogenous amino acids can be synthesized in our bodies; examples include alanine, aspartic acid, and serine. If the number of amino acids linked by a peptide bond in a molecule exceeds 100, it is a protein. They can differ in chain length, but also in size, shape, role, and function in the body. The basic functions of proteins in the body include:
- Building and structural function (creatine, collagen, elastin)
- Transport function (hemoglobin, transferrin)
- Relay function (nerve impulses)
- Storage function (ferritin)
- Immune function (immunoglobulins)
- Control of the growth and differentiation of individual cells
- Regulation of biochemical processes (insulin, growth hormone)
- Hormonal and genetic regulation
- Regulation of muscle contraction (myosin, actin)
- Create buffer
- Control of cell membrane permeability
Proteins play a major role in the proper functioning of our bodies. Therefore, it's worth ensuring a regular intake through food. To do this, you need to know their basic sources.
Proteins of animal origin
Animal proteins are often referred to as complete proteins. This means they contain all the necessary exogenous amino acids. This eliminates the need to pay attention to the composition of specific animal proteins and allows us to be confident that our individual amino acid needs will be met by consuming them. It's also worth noting that the digestibility of these types of products is higher than that of plant-based products, reaching about 96%, while plant proteins reach about 90%. This is due to differences in the amino acid composition of both proteins. Those of animal origin are very similar in structure, composition, and form to those found in our bodies.
Sources of animal proteins
Although proteins of animal origin are very similar, their source is also of great importance. It should be remembered that, in addition to proteins, individual products also contain carbohydrates, fats, and other macro- and microelements. All of this also contributes to the quality of a particular protein source.
Red meat (beef, pork, game, lamb, mutton).
Red meat owes its characteristic color primarily to myoglobin. These types of meat are characterized by their high content of easily digestible and wholesome proteins. They also contain plenty of iron and B vitamins, including the extremely valuable vitamin B12. It's also worth mentioning that they contain a lot of zinc—a nutrient important for maintaining healthy skin, nails, and fertility, among other things. Unfortunately, that barrel of honey also contains a spoonful of tar. Red meat is extremely fatty. It contains a lot of saturated fat, which isn't very good for our health. The same applies to the amount of bad LDL cholesterol. Furthermore, excessive consumption, especially of the fried variety, can lead to colon cancer and cardiovascular disease. Of course, this doesn't mean we should avoid eating it altogether, but rather significantly limit it.
White meat (chicken, duck, turkey, quail, goose, rabbit)
White meat typically contains much less fat than red meat, which is why we often refer to it as lean meat. They are also sources of very easily digestible protein and are less stressful on our digestive systems. For example, 100 grams of chicken breast provides about 22 grams of protein. Due to their low calorie content, they are especially recommended for people who exercise but also want to lose weight. In addition, white meat is a good source of B vitamins, as well as zinc, potassium, magnesium, and iron. It should also be mentioned that, according to recent research, this type of meat carries a much lower risk of various types of cancer, especially those that affect our digestive system. They can also be eaten much more frequently than red meat.
Dairy products (milk, yogurt , cream, kefir, cheese, buttermilk)
Dairy products are also a good source of protein in the diet. However, it's important to remember that individual varieties can vary considerably in their protein content per 100 grams. Even this amount of rennet cheese contains about 20 grams of protein, while 100 grams of milk contains about 3 grams. As you can see, the range of these values is quite large. Nevertheless, dairy products are a very good source of highly digestible protein. It's also worth noting that these types of products contain large amounts of calcium, magnesium, zinc, and copper. Another important benefit of these products is their vitamin content, including vitamins D , A, E, and B. However, remember to choose high-quality products from reliable sources. Nowadays, many active ingredients are added to dairy products to improve their physicochemical properties, which doesn't always have a positive effect on our health. The market leader adds sugar to many products as a filler and to improve palatability. This is quite common in fruit yogurts, for example. Dairy products may also contain lactose—milk sugar. Therefore, people with intolerance should avoid it for obvious reasons.
Fish and seafood
Fish and seafood are the main source of protein for nearly 3 billion people. Add to that the fact that it's a complete protein and can be consumed by vegetarians. The sheer number and diversity of species undoubtedly means that everyone will find something for themselves. However, the protein content also varies greatly. For example, 100 grams of salmon contains about 15 grams, and 12 grams of herring. However, this does not change the fact that seafood is one of the best sources of protein and more. In addition to the relatively high content of this macronutrient, it contains many other nutrients that positively affect our body's functioning. As early as the 1960s, it was observed that the inhabitants of Greenland (Eskimos) suffered significantly less from cardiovascular disease. This was clearly related to the high consumption of marine fish, which are an excellent source of essential fatty acids (EFAs), including omega-3, omega-6, and omega-9 acids. In addition, they can be an excellent source of elements such as zinc, iodine, potassium, phosphorus, sodium, and magnesium. They also contain various vitamins, including vitamins A and D, as well as those of group B. Consumption of these types of foods has also been linked to a reduction in the levels of bad LDL cholesterol and triglycerides in the blood. They can also have a positive effect on the functions of the entire cardiovascular system, improve brain function, and thus significantly reduce the risk of neurodegenerative diseases (Alzheimer's disease, Parkinson's disease).
Eggs as a source of protein in the diet
Eggs are undoubtedly synonymous with complete protein. They are a model product in terms of individual amino acid content, meaning they contain all 20 amino acids. However, in 1965, the World Health Organization recognized them as a model for measuring the content of individual amino acids in other products. A standard 56-gram egg contains about 7 grams of protein, but interestingly, the yolk contains more protein. They are also a good source of vitamins A, E, D, and K. They are rich in phosphorus, potassium, sodium, copper, calcium, zinc, and selenium. Although they have been considered a source of bad LDL cholesterol for years, their fat composition is surprisingly beneficial. For every 10 grams of fat, there are only 0.2 grams of saturated fat. It's worth noting that eggs contain quite high levels of omega-3 and omega-6 acids. However, the problem of cholesterol remains. The fact is that eggs contain quite a lot of it, but you shouldn't be too afraid of it. Its adverse effects are counteracted by other health-promoting substances it contains. Ultimately, LDL cholesterol levels are lowered and the amount of good HLD cholesterol in the blood is increased.
Protein of plant origin – properties
Although protein is more commonly associated with animal products than plant-based ones, you can't ignore the latter. While these products can provide us with sufficient protein, there are a few important things to keep in mind. First, it's slightly less digestible than animal protein. This difference ranges from 10% to 40%, depending on the product. This is because plant-based products contain a lot of fiber and phytic acid, both of which impede absorption. Furthermore, plant proteins contain incomplete or insufficient amounts of exogenous amino acids. Therefore, you shouldn't eat just one or two of these products, but rather strive to make such a diet as balanced as possible. This is especially important for vegetarians and vegans. The former should combine dairy products with legumes to provide the body with a complete set of amino acids. Vegans, on the other hand, have a somewhat more difficult task due to the complete avoidance of animal products, but it is also doable. To this end, they should eat legumes, nuts, and grains. Such a varied diet certainly allows you to provide the body with sufficient exogenous amino acids. It's also worth mentioning that due to the lack of red meat in the diet , vitamin B12 supplementation is also recommended.
Legumes
Legumes are considered one of the basic sources of plant protein. Soy is also worth mentioning, as it has the highest digestibility. Its share is about 90%, so it's not surprising that soy is the basis of many other products, such as tofu, soy milk, tempeh, cream, and soy yogurt. Legumes as a product group are characterized by a high content of protein, as well as fiber and microelements. They contain a lot of calcium, phosphorus, magnesium, potassium, and even iodine and B vitamins. The most popular representatives of this group include soybeans , chickpeas, lentils, green peas, peas, white beans, and red beans.
Cereals and pseudocereals
Grains and pseudocereals are the next protein source on our list. These plants are often an important ingredient in other popular products such as pasta, groats, bran, and even baked goods. In addition to protein, they contain a lot of complex carbohydrates and fiber, making them a good source of energy. They also contain silicon, calcium, and B vitamins. It's worth mentioning that these plant products can also cleanse the body of unnecessary metabolic waste and speed up metabolism. Interestingly, these pseudocereals are called amaranth and quinoa. However, products in this group that contain relatively high levels of protein include wheat bran, oat bran, bulgur, whole-wheat pasta , millet, and the aforementioned pseudocereals.
Seeds and nuts
Seeds and nuts are an excellent source of plant protein. Pumpkin seeds contain up to 30 grams per 100 grams. But the good news doesn't end there, because they also contain omega-3 acids. These compounds are essential for the proper functioning of our cardiovascular system and the heart itself. They can also provide us with many minerals, including magnesium, phosphorus, calcium, zinc, potassium, and iron. B and E vitamins, as well as a high fiber content, are also the strengths of nuts and seeds. However, keep in mind that despite their many health-promoting properties, they are high in calories, so try to eat them sensibly. Among the most popular representatives of this group are hazelnuts, walnuts, cashews, almonds, as well as sunflower seeds, pumpkin seeds, and chia seeds.
Summary
There are many sources of protein, whether animal or plant-based. This means that everyone is sure to find something that suits them both organoleptically and ideologically. Of course, each of the product groups mentioned here has both advantages and disadvantages. This is why it is so important to combine different protein sources in your diet. This applies not only to vegetarian or vegan diets. This approach also ensures that, in addition to amino acids, other, equally important chemical compounds reach our bodies. Furthermore, with a little variety, our daily diet will certainly become less monotonous, and we can discover new flavors in the kitchen.
