nitrogeninntak

Nitrogeninntak is the amount of nitrogen that enters the body through food and beverages. In nutrition science, it is used to assess protein intake and to estimate nitrogen balance, an indicator of body protein status. Most dietary nitrogen comes from protein, while other nitrogenous compounds contribute little to daily intake.

Nitrogen intake is commonly estimated by converting protein intake to nitrogen using the standard factor 6.25: nitrogen (g) = protein (g) / 6.25. Conversely, protein intake can be estimated from nitrogen by multiplying nitrogen by 6.25. Total nitrogen losses include urinary nitrogen (mainly urea), fecal nitrogen, sweat, and other minor routes; urinary nitrogen is often the main measurable component.

Nitrogen balance is the difference between intake and losses. A positive balance indicates tissue accretion (growth, pregnancy, muscle gain); negative balance indicates net protein loss. In healthy adults, the recommended protein intake is about 0.8 g per kilogram of body weight per day, which for a 70 kg person equals roughly 56 g of protein or about 9 g of nitrogen daily. Actual intake varies with age, activity, and health status.

Dietary sources of nitrogen include animal-based proteins (meat, dairy, eggs) and plant-based proteins (legumes, grains, nuts). The distribution of intake across meals and the overall amino acid profile influence nitrogen utilization and health.

In clinical contexts, nitrogen balance assessment supports nutrition planning, especially for athletes, older adults, pregnant people, and individuals with kidney disease or trauma. Limitations include method accuracy and unmeasured non-urinary nitrogen losses.