Question: 5. Using Guidance From The Calculation Comer Regarding Nitrogen Balance On Page 224, Where It Is Noted That Protein Is, On Average, 16% Nitrogen By Weight, Suppose That A Person With Moderately Severe Chronic Kidney Disease Eats The Meal Described. This Individual’s UUN Is Correspondingly Decreased To 4 G In 24 Hours, With The Associated Factor For …

5. Using guidance from the Calculation Comer regarding nitrogen balance on page 224, where it is noted that protein is, on average, 16% nitrogen by weight, suppose that a person with moderately severe chronic kidney disease eats the meal described. This individual’s UUN is correspondingly decreased to 4 g in 24 hours, with the associated factor for other difficult-to-measure compounds and molecules also decreased thereby. What would this individual’s nitrogen balance be, and what should he or she probably do instead? (Hint: Looking at the following calculation, where the RDA for protein is established based on weight, as well as the reasonable standard (50 g) that manufacturers generally use to calculate % DV if they make a protein-related health claim, as noted a few pages later, we can see that this, as a single meal, is very high in protein for anyone 6. Looking back in the same calculation question as above, regarding nitrogen lost through other means such as skin, how, aside from normal sloughing of skin cells, might one lose protein and thus nitrogen through the skin? As a hint, think about what might happen while exercising outside on a hot day. Calculation Corner Nitrogen Balance (a) Using the fact that protein is 16 percent nitrogen, a common factor of 6.25 is used to calcu late how much nitrogen is in a given amount of food (100/16 = 6.25). We analyzed the food and beverages from a meal and found that it contained 73 grams (g) of protein. Divide this by 6.25 to determine the nitrogen content of the meal: 73 g protein Nitrogen 11.6 g of nitrogen 6.25 g nitrogen (b) Now calculate the amount of nitrogen lost from the body. First, nitrogen is lost in the urine 2 urea nitrogen, and in other nitrogen sources that are not part of the urea molecule. Because it’s difficult to account for the non-urea sources directly, a factor of 0.2 grams X urinary urea nitro- gen (UUN) is used to determine these losses. In this example, let’s assume we analyzed the urine and found 8 grams of UUN. The total nitrogen lost in the urine would be calculated as follows: 8 g UUN + (0.2 x 8 g UUN) = 9.6 g nitrogen lost (C) Next, we must account for nitrogen lost through other means, including hair, skin, and feces–approximately 2 grams per day. Add this to the equation. 8 g UUN + (0.2 x 8 g UUN) + 2 g = 11.6 g nitrogen lost (d) Now let’s put it all together with the equation: Nitrogen balance = nitrogen in-nitrogen out Nitrogen balance = (73 g protein/6.25) – (8 g UUN + 10.2 x 8 g UUN) +29) = 0 g of nitrogen The calculation for nitrogen balance can be Scan this QR code with your mobile OSD useful to dietitians as well as researchers to device to access practice math activi- determine protein requirements, ties. You can also access the activities in Mastering Nutrition”: