What are proteins?
Proteins, also called proteins, are among the main nutrients (besides carbohydrates and fats). Proteins are composed of amino acids and are among the basic building blocks of all cells. Every organ and every muscle consists of proteins. Only in emergency situations does the body fall back on protein - it is not used for energy production. Only in zero diets or heavy physical exertion is energy drawn from proteins - in these cases unwanted muscle breakdown occurs. Among other things, proteins are building blocks of enzymes, hormones, muscles, antibodies and storage proteins.
How is the digestion and absorption of protein?
The digestion of protein begins in the stomach. Hydrochloric acid changes its structure and an enzyme breaks it down. The actual digestion takes place in the small intestine.
If the protein comes from animal food, it is absorbed faster and more easily, as no cellulose cover delays its absorption (as with protein from vegetable sources). Among the main nutrients, proteins have the highest thermogenic effect (18 - 25%). This is the amount of energy required for food intake and utilization. If we look at the values of carbohydrates (4 - 7%) and fats (2 - 4%) in comparison, it is noticeable that the food-induced thermogenesis after a protein-rich meal lasts about twice as long as after a carbohydrate- or fat-rich meal. The body therefore needs considerably more energy when eating and using food. Especially in prevention and therapy this aspect should be considered. The distribution of nutrients should be modified accordingly in favour of proteins. In the human organism, proteins are subject to a permanent build-up and breakdown. Normally the degradation corresponds quantitatively to the structure. The amino acids resulting from the breakdown are recycled and serve for new formation.
Essential amino acids must be supplied through food. The better the amino acid pattern of the food protein corresponds to the amino acid requirements of the body, the higher the biological value. The best combination of foods that achieve a high biological value is the combination of potatoes and egg.
What happens in case of protein deficiency?
If there is a lack of protein, the muscles and depot fat are often broken down, which leads to weight loss (underweight / malnutrition). These weight losses are to be assessed negatively, as they are caused by muscle breakdown (muscles are heavier than fat).
Meat, fish, certain dairy products, egg and legumes are rich in protein.