Nitrogen Balance

Your Nitrogen balance is basically whether you have enough or too little. Protein is the only macronutrient that contains Nitrogen. Carbs and Fats do not. When you eat protein, and it is broken down (from food or muscle), Nitrogen is excreted, mainly in the urine. 

Simple measures:

Protein is the only macronutrient that contains Nitrogen. Nitrogen balance is the difference between:

Nitrogen in (from dietary protein)
vs.
Nitrogen out (from breakdown and excretion)

IF YOU HAVE A:

Negative Nitrogen Balance. 

This occurs when urinary nitrogen losses exceed dietary nitrogen intake. A negative Nitrogen balance suggests a loss of Nitrogen, which in turn is associated with a loss of muscle protein.

Positive Nitrogen Balance.

This occurs when you're retaining more Nitrogen than you're losing, muscle growth & recovery are occurring.

Drifting into negative nitrogen balance is one of the hidden drivers of Sarcopenia. 

HOW DOES LEUCINE FIT?

Leucine has no "extra" Nitrogen compared to other Amino Acids. Leucine is the signal for protein synthesis. Nitrogen balance is the scoreboard.

Think of Leucine as the referee blowing the whistle to start the game.

The connection - Overview

1. Protein provides Nitrogen
2. Muscle growth requires retaining Nitrogen
3. Leucine tells the muscle to use the amino acids for building
4. Without enough Leucine, the protein intakemay not shift to a positive balance
5. Muscle synthesis remains blunted. Negative balance is more likely. Muscle decline.

When the Lecuine Threshold is reached:

• Muscle-building pathways activate
• Amino Acids are incorporated into muscle
• Nitrogen retention improves
• A positive balance is more achievable.

IN A NUTSHELL

Leucine = Ignition Key

Complete Protein = Building materials

Nitrogen Balance = Measurement of outcomes

TRAINING

Link between protein intake, skeletal muscle function, and health in older adults. definitely worth a read (NIH)  Leucine meal increases glutamine and total nitrogen release from forearm muscle. (PubMed)