Proteins

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They made life possible on earth. It is building component of every tissue in human body, including bones. Soft tissues contain 75% of proteins. Its made of nitrogen, carbon, hydrogen, oxygen, sulfur and sometimes calcium, phosphorus, iron, copper, iodine, zinc, magnesium, cobalt and manganese. Proteins are found in two forms - simple and complex. Simple proteins are only made of aminoacids (lymph protein, protein of blood serum, milk, muscle, legumes, grains, etc.). Complex proteins contain extra non protein ingredient, so called prosthetic group.



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In terms of biological value for human body, proteins supplied with food are divided into two groups - those rich in aminoacids and those with lower numbers of amino acids. This classification depends on how much and in what proportion proteins contain essential aminos. There are 10 aminos that our body cannot synthesise by itself - phenylalanine, isoleucine, methionine, lisine, leucine, threonine, tryptophan, valine, arginine and histidine. Wholesome proteins are found in animal products: meat, fishes, poultry, offal, milk, cheese and eggs. The only animal protein that is not wholesome is gelatine. Sources of proteins that are not so rich in aminos are plants and products based on those: legumes, flour, bread, pasta, groats and potatoes. Exception is soy protein which is similar in case of aminos to proteins of human body.


In proteins, even those wholesome, essential aminoacids are found in different numbers and then the one which numbers are smallest is the one which decides about how efficient protein synthesis in human body is. The undisputed king of proteins is ofcourse egg.
Vegetable proteins can be of great use when served with animal proteins. Good idea for breakfest is then bread with white cheese or oatmeals with milk or bread with eggs etc. Another example is pasta with eggs or cheese, pancakes with cheese etc. In other words cheese and eggs are great in many forms but real meaning is that mixing animal proteins rich in aminos with plant proteins is the way to go. Best ratio of animal to plant proteins is 1 : 1. For physically active people animal proteins should be 2/3 of whole protein intake while plant proteins 1/3. In other words its 1 : 0,5 ratio for physically active people.

Why proteins are so important in sport

Proteins are generally used as resource to repair our tissues yet unused aminos will always be transformed into glucose, ketones or fat which are used as energy sources. Aminos that can be transformed into sugar are: glycine, serine, cysteine, aspartic acid, glutamic acid, proline, arginine and histidine. Aminos that can be transformed into fat are: valine, leucine and isoleucine. Ketogenic aminos are: phenylalanine and tyrosine as well as all of those that can be transformed into fat. Fact is that only 10 - 15% of aminos we consume are used as energy source. Usefullness of proteins as energy resource is more important when ones dietary plan is unbalanced and lacks carbohydrates and / or fats. Then our body can transform up to 48% of proteins into glucose and 46% into fats. Sadly, our body can use our own proteins when starving which may lead to consuming muscle tissue. Consuming too much of proteins is not only bad because it may lead to obesity but it can also damage kidneys and cause dehydration or calcium deficits.

How much proteins to consume then ?

• for people who are not practicing sports: 1g per 1kg of body mass
• for people who are physically active: 2,5 - 2,8g per 1kg of body mass
  
  
  Good thing to remember is that balanced dietary plan contains proteins as well as carbohydrates and fats in healthy ratio. Each nutrient has its role in our body either you are physically active or not. For more information about nutrition look into my other posts. Thank you for reading and stay healthy :)