Assuming that an 21 year-old female weighing 135 lbs requires 0.8 g protein/kg b
ID: 64046 • Letter: A
Question
Assuming that an 21 year-old female weighing 135 lbs requires 0.8 g protein/kg body weight per day to be in zero nitrogen balance, she would need 49.09kg of dietary nitrogen would to meet her individual needs.According to the previous question, how many grams of dietary nitrogen would be excreted in the urine assuming that losses through in the feces or from the skin (and other insensible losses) account for 6% of nitrogen losses per day? In what form is the majority of the urinary nitrogen excreted?
Explanation / Answer
Nitrogen excretion cannot be reduced below a certain amount despite the reduction to zero intake. This amount is called the ‘obligatory nitrogen losses’ (ONL), which represent the nitrogen loss that is measurable in subjects fed a protein-free diet for a relatively short period of time. The amount of nitrogen excretion in urine would amount to about 36mg/kg/body weight.
Her dietary nitrogen of 49.09kg would be excreted in the urine at 1727 grams of nitrogen in the urine.
The primary form of nitrogen excretion in humans is urea which represents over 85% of the total excretion of nitrogen. While uric acid represents only a small percentage of total nitrogen excretion.