Nitrogen Balance is the difference between the amount of nitrogen consumed per day, and the amount of nitrogen excreted per day.
Nitrogen balance —> Gram of N eaten – Gram of N loss
Nitrogen balance experiment therefore requires measurement of the amount of nitrogen consumed per day;for several days.This is easy to measure because all the nitrogen consumed enters the body through the mouth.The amount of nitrogen consumed,can be determined from the weight of the amount of food consumed and the knowledge of the nitrogen content (By Kjeldahl method).Nitrogen balance experiments also requires measurement of the amount of nitrogen excreted per day for several days.This measurement requires the collection urine,sweat, and faeces.Quantitative collection of these materials,homogenization of the faeces and analysis of the nitrogen content of both urine and faeces can be tasking particularly when hundreds of samples are involved.A meaningful value for nitrogen balance cannot be determined by analyzing the food and excreter collected during one day,because of biological variability samples must therefore be collected over several days.In normal adult,protein balances with degradation and protein intake must balance with the nitrogen excretion in urine,faeces and sweat.
When nitrogen intake,equals nitrogen output,the person is in nitrogen equilibrium or zero in balance.If the body synthesizes morethan it degrades,nitrogen status becomes positive.Nitrogen status is positive in growing infant and children,pregnant women and people recovering from defficiency or illness.Their nitrogen intake exceeds their nitrogen output.They are retaining protein in new tissues(infants,children and pregnant women) as the add blood,bone,skin and muscle cells to their bodies.
If the body degrades more-than it synthesizes and losses protein,nitrogen status is negative in people who are starving or suffering other severe stresses such as burns,injury,infections,fever etc.
Their nitrogen output exceeds their nitrogen intake.During this time,the body losses nitrogen s it breaks down muscles and other body protein for energy.Nitrogen Equilibrium= Nin=Nout
Negative Nitrogen= Nin<Nout