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Nitrogen balance

Added: August 28, 2015 10:25 am

As bodybuilders and athletes, we are more or less aware of the importance of taking proteins. But how do we know if we are taking in enough protein? Let’s have a look at it from the point of view of nitrogen balance.

Building processes are based on the triplet of training, rest and nutrients. From a nutritional aspect, protein has a special role, since 60-70% of protein can be found in muscles. Protein is the key to building muscles, as well as a number of other tissues, many of which also support muscle growth (enzymes, skin, hair, nails, bones and connective tissue – all of them are built up of protein). Protein in our body makes up for about 15-20% of our body mass.

Muscles, therefore, are made from proteins. Proteins, on the other hand, are made of amino acids – essential and non-essential amino acids. Our body is incapable of producing essential amino acids, therefore we need to take them in with food. Non-essential amino acids are produced by the liver. Note that the quality and ratio of essential and non-essential amino acids is the key to muscle mass growth.

Essential amino acids are:

  • histidine
  • isoleucine
  • leucine
  • valine
  • lysine
  • methionine
  • phenylalanine
  • threonine
  • tryptophan

Non-essential amino acids are:

  • alanine
  • arginine
  • asparagine
  • asparagine acid
  • cysteine
  • glutamic acid
  • glutamine
  • glycine
  • proline
  • serine
  • tyrosine

In order to provide your body with the right ratio of essential and non-essential amino acids, it’s important that you should consume complete protein sources such as eggs, dairy products and animal protein based shakes. Plant-based proteins are not complete proteins; however, they can be ‘completed’ by combining with other plant-based proteins (e.g. the amino acids found in rice and peas greatly complement each other). However, in order to create an optimum anabolic environment, it’s simpler to consume animal proteins!

Nitrogen balance

By measuring the quantity of nitrogen, we can exactly find out whether our body gets the amount of protein needed for growth and development or not. Nitrogen is the only component in proteins which can indicate this state. Therefore, through nitrogen excretion, it is measurable what phase/state the body is in. To be exact, it’s the amount of carbamide, a nitrogen-containing metabolic product in one’s urine that indicates the presence or lack of nitrogen balance.

The states of nitrogen balance:

  • Positive: From the point of view of muscles growth, it’s the optimum state, when nitrogen intake is higher than nitrogen loss. It contributes to recovery and development and creates an anabolic (building) state.
  • Negative: It is characterised by the presence of catabolic, decomposition processes, when nitrogen loss is higher than nitrogen intake. It poses a risk of muscle decomposition.
  • Balance: It is the state that an athlete should at least maintain. In this state, nitrogen intake equals loss. Although there is no muscle decomposition, there is no muscle growth, either.

How the amount of nitrogen can be measured:

On the one hand, it can be calculated from the carbamide level of urine; however, in scientific practice, the nitrogen content of foods is compared to that of urine (measuring nitrogen output within 24 hours).

How the state of negative nitrogen balance can be achieved:

  • overtraining: during training, the decomposition of muscle tissues begin at a certain level, and development can be achieved through sufficient food intake and rest; when these two are missing, too much training will only trigger decomposition processes
  • insufficient carbohydrate and fat consumption with high protein intake: proper protein synthesis requires all three macronutrients. When there is too much protein and insufficient high-quality carbohydrate and fat, your body will not transfer proteins to your muscles, but use them to ensure the functioning of your organs, producing energy from protein
  • low protein intake (less than 0.5 g/kg of body weight)

How a positive nitrogen balance can be achieved:

  • sufficient complete protein intake: it means about 5-6 meals a day, each with 30-40 g protein
  • after training, you should consume protein and carbohydrate together, because carbs enhance protein uptake
  • before going to bed, you should consume slow absorbing proteins such as caseine
  • sufficient quantity and quality of rest
  • training only after a sufficient recovery period

How much protein a bodybuilder needs in general

Our minimum protein intake is 1 g/kg of body weight per day; for an average person, the recommendation is 0.8 g/kg of body weight. For bodybuilders, the recommended quantity varies between 1.7 g and 2.5 g/kg of body weight. You shouldn’t consume more than that because it would only burden your body, mainly your kidney, and it won’t absorb. It’s not recommended to take in more during a special diet, either, despite the fact that you can sometimes read about quantities as high as 3-4 g/kg of body weight. For amateur athletes, 1.5g/kg of body weight is more than sufficient to create a positive nitrogen balance.

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