Using Anabolic Signalling in Training and Nutrition

It is well-known that nutrition influences the adaptive responses of training on muscle mass and function. Therefore, in order to determine the optimal training adaptions, first we have to determine the nutritional and training catalysts. An evidence-based approach is of course the most effective way of generating nutritional and training recommendations, but the various interpretations of scientific literature can be ambiguous, and therefore problematic. 

The response of anabolic signalling pathways to different types of nutrition and training interventions has recently been investigated and the molecular anabolic pathway which has been primarily investigated is the mTORC1. The response of the mTORC1 to nutrition and training has been studied in animal models for over 20 years and it is now quite clear that the activity of the mTORC1 is critical for the optimal stimulation of muscle protein synthesis, and therefore muscle adaption.

The mTORC1 Signalling Pathway

It is known that the mammalian target of rapamycin (mTOR) pathway plays a vital role in the regulation of protein synthesis and recent studies in humans have contributed more crucial information. There is even evidence to show a relationship between the response of the mTORC1 pathway and muscle hypertrophy.

However, it can be argued that the evidence on the response on anabolic signalling pathways to nutrition and training should not be the only data on which to base recommendations, as there a number of limitations to the measurement of the response on anabolic signalling.

Findings of Recent Studies

Recent studies on the relationship between anabolic signalling and nutrition and exercise has found the following:

  • Blocking the mTORC1 pathway hinders the response of muscle protein synthesis to resistance exercise and protein. Much like blocking online betting NZ would hinder this popular pastime!
  • Proteins – which are essential amino acids – and resistance exercise both stimulate the mTORC1 signalling pathways independently.
  • Studying and measuring the responses of these pathways is easier and more cost-effective than attempting to study muscle protein synthesis or doing a training study for an extended period of time.

As such, it becomes easy to see why using this information alone can be tempting to inform practical recommendations on training and nutrition.

Contradictory Scientific Findings

However, there is a big ‘but’ to be found here. Recent studies from various laboratories have shown that there is often a mismatch between the responses of anabolic signalling pathways and muscle protein synthesis and there are a number of methodological reasons for these mismatches. In order to measure signalling protein, small biopsies of muscle are made, and due to the invasive nature of this practise, scientists have had to make a decision as to when to take the biopsies as they cannot be done too often.

The following issues have been highlighted:

  • A particular intervention, for example the ingestion of whey protein, results in a greater molecular response 2 hours after ingestion, so how can we be sure that the response may not be greater with ingestion of a different protein source at 1 hour?
  • A potential threshold effect has also been highlighted as typically the activity of the mTORC1 pathway is assessed by measuring phosphorylation of the proteins in the pathway. As such, if the ingestion of a certain protein (A) results in greater phosphorylation than the ingestion of a different protein (B), it would suggest that protein A results in greater muscle protein synthesis and is therefore superior to protein B.

It therefore becomes clear that recommendations for nutrition and exercise cannot be based on anabolic signalling pathways alone.