What is the Nitrogen Balance?

What is the Nitrogen Balance?

The Nitrogen Balance is a term used to describe the rate of protein synthesis and breakdown

What is the Protein Turnover?

The protein metabolism consists of a series of physiological processes that result in what is known as “protein turnover”.

The protein turnover is the connection between the protein synthesis and breakdown. A positive balance for the synthesis is called “anabolism”. On the contrary, if the breakdown is higher it would be called “catabolism”.

The truth is that all the cells from all the organic tissues go through both processes: synthesis/breakdown.

For many years, people have used the term “nitrogen balance” to measure the protein turnover.

Amino acids and Nitrogen

Proteins and peptides are made up of amino acids that have Nitrogen atoms. This is one of the best ways to measure the protein content from food. In fact, the AECOSAN (Spanish Association of Food Safety and Nutrition) tends to use the Kjeldahl method. Said method measures the nitrogen charge from food.

Although this method is problematic since there are non-protein nitrogen molecules.

Kjeldahl Method

Figure I. Kjeldahl method stages to assess the protein content from food

The nitrogen balance technique has been used thanks to its non-invasive features. To put it briefly, the procedure basically consists of measuring the nitrogen intake – nitrogen excretion. Therefore, a positive balance would be PS (protein synthesis) > PB (protein breakdown). On the other hand, a neutral balance would be PS=PB, and a negative balance PS<PB.

However, this technique is quite limited when it comes to: the validity of the dietary quantification, non-reported behaviors, measuring mistakes and incomplete urine collection in 24h. (Halliday & Rennie, 1982)

This is due to the fact that universally, people tend to reduce the concept  of protein turnover to the nitrogen balance. However, the latter is just another method to try to assess the protein metabolism.

Poortmans et al. (2012) show how there are more techniques:

1. Non-invasive

  • 2H20 Intake
  • Whole body nitrogen balance
2. Invasive
  • Whole body protein turn over assessments by diluting the markers on plasma amino acids (stable isotopic markers)
  • Assessment estimation of tissue protein synthesis through the artery-vein differentiation
  • Other less accepted recent methods
As we can see, there are many techniques for this purpose, although it has been reduced to the nitrogen balance due to practical reasons.

Anabolism and Catabolism

The connection between the protein synthesis and protein breakdown results in anabolic/catabolic processes

They interchange, for instance, an exhausting physical exercise will trigger a catabolic process. On the contrary, a post-workout recovery will trigger an anabolic process if we have enough nutrients.

Amino acid capsules and powder

Taking protein is crucial to ensure said anabolic process

Moreover, producing a prolonged aminoacidemia is more effective than producing an acute amino acid plasma release. This is due to the fact that they will be oxidized, transaminated and not utilized.

In other words, the protein digestion and absorption rate is extremely important when it comes to producing a positive protein balance.

Protein absorption and amino acid release

There is a huge misconception about the protein absorption

A great percentage of the population believes that taking protein with fats and/or carbohydrates prolongs the amino acid release in the plasma. This is a huge mistake because people associate the reduction of the GI from carbs when combined with other nutrients.

The truth is that the digestion and absorption can be slightly altered, but it does not alter the amino acid release, their bioavailability nor the synthesis of protein microfibrils.

Protein sources

This results in the absorption kinetics of protein (concept from pharmacology), which is reduced from the food source and not in the nutrient combination per se

In general, that is why it is interesting to take protein with slower absorption kinetics except for specific moments like the peri-workout nutrition or after waking up. The amino acid release will be progressive, resulting in a prolonged aminoacidemia and less oxidation.

Factors that determine the quality of a protein

According to the what Hoffman & Falvo exposed in the ISSNS (2005), what determines the quality of a protein source is:

  • Protein scale review
  • Protein efficiency rate
  • Biological value
  • Net utilization percentage
  • Protein digestibility corrected amino acid score

To determine the quality of a protein source, it is necessary to reduce the compensation of the previous factors

That is why vegetable proteins, even those that have a complete aminogram “tend to have a lower biological value, protein utilization, PDCAAS and protein efficiency rate than animal proteins”.

Protein quality review

Figure II. Protein quality assessment chart from different foods. Taken from Hoffman & Falvo (2005).

That is why eggs and dairy products have better scores in the protein quality ranking. However, when we deal with milk proteins, we know that they are not all the same.

There is whey and caseinate (calcium, sodium and micellar casein)

Leucine content graphic

Figure III. (A) Plasma leucine content, (B) marker 2H3 enrichment in infusion I.V., and (C) marker 13C enrichment taken orally after a meal made of whey protein (13C-WP study) and casein (13C-CAS study). Taken from Boirie et al. (1997)

As you may have noticed, they all have different absorption rates. However, Whey is the one that releases more amino acids faster and for a shorter time than casein. (Boirie et al., 1997).

Evonight 2.0 by SportSeries

That is why blending proteins, also known as time released proteins, is a very useful choice.

We will take advantage of the fast amino acid release from whey and the prolonged aminoacidemia from caseinate.

That is why HSNstore came up with Evonight 2.0, a time released protein whose main sources are:

  • Whey protein (Concentrate and Isolate)
  • Egg albumin
  • Milk protein and caseinate

Combining three quality protein sources with different absorption kinetics results in a great net protein utilization.

Our purpose should be to prolong a Positive Nitrogen Balance as long as we can. For this, it is necessary to have nutrients available in our bloodstream, that is, amino acids.

Therefore, it will be quite helpful to take a product that will provide amino acids when we are not eating any food. In fact, it will help us advance towards our goals and gains.

Producing a Positive Nitrogen Balance will be key for a proper recovery, regeneration and growth of muscle tissues

Evonight is a protein that we can take on a daily basis, at any time, not only at night; an all-terrain protein!

Nitrogen Balance States


This is the optimal state for muscle growth

It is when we consume more nitrogen than the one we excrete. It basically indicates that the body has properly recovered from the last workout. The more capacity to retain nitrogen, the faster the recovery processes will be.


This is the worst state for a bodybuilder and it happens when we lose more nitrogen than what we take.

In this case, we do not only lose nitrogen for muscle growth, but also the one that is used by vital organs, which can result in serious damage. Of course, a negative nitrogen balance destroys the muscle and the body is in a catabolic state.


This state would be less worse than the former, specially because it avoids catabolism. However, there are no muscle gains, since the amount of nitrogen that we consume is the same that the one we excrete.

After a workout, the organism will absorb the nutrients like a sponge, which is the so called the post-workout anabolic window. But said phenomenon does not last for a certain period of time, rather, it is precisely the result of the body wanting to fix the damaged tissue as soon as possible.

How Can we Achieve a Positive Nitrogen Balance?

The main principle will be to take an good supply of proteins. In fact, a constant intake of this macronutrient during the day should be enough to meet this premise.

If you want to preserve this balance to grow as much muscle as possible, you can use the following scheme:
  • To minimize muscle breakdown during the workout, we will create an insulin increase (anabolic hormone which enhances the absorption of amino acids and glucose for muscle cells) by drinking fast absorption carbohydrates and amino acids or whey, around 30-60 minutes before the workout
  • Consume the same blend once the workout is over, which will stimulate the protein synthesis
  • Before sleeping, meeting the daily amount of protein, take a drink made from time released proteins
  • Sleep properly. This is the period when our body creates muscle since the stimulus is over (workout)

Anabolic Training

Physical exercise is already anabolic, since it creates the necessary stimulus for the body to focus on the protein synthesis. At this point, we have to properly plan the workout to enhance said stimulus.

Training at the gym

The idea is to stimulate as much muscle fiber as possible to trigger a positive nitrogen balance with the lowest muscle breakdown.

Once the workout session is over, the muscles should be in an anabolic state in order to trigger a positive balance. However, when the workouts are too long, the muscles are exhausted, which produces a catabolic state.

If we want to perform an anabolic training:

  • We have to train when the body after completely recovering from the last workout, that is, when our body is in a positive nitrogen balance
  • Short and intense workouts, around 45-60 minutes
  • Prioritize basic exercises: squats, deadlifts, push press, row, bench press, pull ups, …
  • Train again once you are completely recovered
Dorian Yates and Mike Mentzer used to follow a type of workout known as “Heavy Duty”, which provided remarkable results. There is no doubt that they have a positive nitrogen balance…


  1. Boirie, Y., Dangin, M., Gachon, P., Vasson, M. P., Maubois, J. L., & Beaufrère, B. (1997). Slow and fast dietary proteins differently modulate postprandial protein accretion. Proceedings of the National Academy of Sciences of the United States of America, 94(26), 14930–14935.
  2. Halliday, D., & Rennie, M. J. (1982). The use of stable isotopes for diagnosis and clinical research. Clinical Science (London, England : 1979), 63(6), 485–496.
  3. Hoffman, J. R., & Falvo, M. J. (2004). Protein – Which is Best? Journal of Sports Science & Medicine, 3(3), 118–130.
  4. Poortmans, J. R., Carpentier, A., Pereira-Lancha, L. O., & Lancha, A. J. (2012). Protein turnover, amino acid requirements and recommendations for athletes and active populations. Brazilian Journal of Medical and Biological Research = Revista Brasileira de Pesquisas Medicas e Biologicas, 45(10), 875–890. https://doi.org/10.1590/S0100-879X2012007500096
  5. Schoenfeld, B. J., & Aragon, A. A. (2018). How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Journal of the International Society of Sports Nutrition, 15(1), 10. https://doi.org/10.1186/s12970-018-0215-1

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About Alfredo Valdés
Alfredo Valdés
He is a specialist in metabolic physiopathology training and in the biomolecular effects of food and physical exercise.
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