There are only a few words that can scare even the greatest of body builders, and "Nitrogen Balance" is at the top of the list!
Let's
take a step back... Our body is in a constant state of protein
turnover, where proteins taken with our diet and supplements assimilate
due to an anabolic boost, and are wasted due to catabolism. Some amino
acids get oxidized and we experience general drop in nitrogen. Nitrogen
is eliminated in
a number of ways, for example, through perspiration, urea, and other bodily secretions. Therefore, Nitrogen Balance is the difference between nitrogen assimilated through the diet, or better, through proteins, and nitrogen eliminated from our body due to our natural physiological functions. The person who absorbs more nitrogen than he wastes will have a positive nitrogen balance, while the person who absorbs the same amount of nitrogen he wastes will have a neutral balance. Correspondingly, the person who absorbs the less nitrogen he wastes will have a negative nitrogen balance, and therefore, a reduction in body proteins. Essentially, nitrogen waste occurs due to the oxidization of amino acids; not only those amino acids absorbed through the normal diet, but also those amino acids that are part of the tissues in natural degradation that exist due to catabolism.
a number of ways, for example, through perspiration, urea, and other bodily secretions. Therefore, Nitrogen Balance is the difference between nitrogen assimilated through the diet, or better, through proteins, and nitrogen eliminated from our body due to our natural physiological functions. The person who absorbs more nitrogen than he wastes will have a positive nitrogen balance, while the person who absorbs the same amount of nitrogen he wastes will have a neutral balance. Correspondingly, the person who absorbs the less nitrogen he wastes will have a negative nitrogen balance, and therefore, a reduction in body proteins. Essentially, nitrogen waste occurs due to the oxidization of amino acids; not only those amino acids absorbed through the normal diet, but also those amino acids that are part of the tissues in natural degradation that exist due to catabolism.
In
order to have a neutral nitrogen balance, a person needs roughly 50mg
per kilogram each day. As an example, a 100kg man will lose almost 5
grams of nitrogen per day, in other words, 30 grams of protein per day
(as nitrogen is 15%-16% protein). For this reason, the protein RDA is
about 0.8 grams per kilogram per day. This quantity is enough to achieve
a neutral nitrogen balance for most people with a sedentary lifestyle.
Obviously, those needs may be subjected to changes or modifications due
to our age, lifestyle, and most importantly our training. Power athletes
usually need 1.6-1.8 grams of protein per kilogram in order to achieve a
positive nitrogen balance and consequent protein storing in their
bodies. Pro body builders have been known to consume up to 2.5 grams of
protein per kilogram, but those are extreme cases.
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