PAN Promet - The Effect of Oral Ingestion of Animal and Plant-Based Proteins on the Somatotropic Axis

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Background

 More and more research focuses on the effect of plant-based proteins on the human metabolism, not least because certain metabolic changes may increase the risk of non-communicable diseases – a leading cause of death worldwide¹.

An important driver of anabolic metabolism is growth hormone (GH) – a central part of the somatotropic axis – which is not only crucial for postnatal growth but also plays a significant role in metabolic regulation across the life span. Upon its release, GH can act directly on target tissues such as the liver, muscle, bone, and adipose tissue or indirectly by stimulating the secretion of insulin-like growth factor-I thus affecting fat, protein and glucose metabolism.

Previous studies have demonstrated that oral administration of proteins, such as soy protein, gelatine, a-Lactalbumin, and milk protein can stimulate GH secretion, with gelatine exhibiting the most pronounced effect. It is hypothesised that the amino acid composition of these proteins, particularly the concentration of arginine, may be a key determinant of the magnitude of the observed effects⁴.  

However, the underlying mechanisms of the differential stimulative effects remain incompletely understood and knowledge regarding alternative plant-protein sources such as pea- or faba bean protein is limited.

Objectives

The aim of this project is to investigate how oral ingestion of pea protein isolate, faba bean protein isolate, and whey protein isolate affects the secretion of GH and other hormones related to the somatotropic axis also taking different amino acid compositions into account.

The underlying primary outcome is defined as the postprandial release of GH during 3h after oral ingestion of plant-protein test drinks vs. an animal-protein test drink.

As secondary outcome, the effect of the oral intake of proteins from different sources on hormones related to the somatotrophic axis will be evaluated as well as the kinetics of amino acids uptake.

References:

1. Bennett, J. E., Stevens, G. A., Mathers, C. D., Bonita, R., Rehm, J., Kruk, M. E., Riley, L. M., Dain, K., Kengne, A. P., Chalkidou, K., Beagley, J., Kishore, S. P., Chen, W., Saxena, S., Bettcher, D. W., Grove, J. T., Beaglehole, R., & Ezzati, M. (2018). NCD Countdown 2030: worldwide trends in non-communicable disease mortality and progress towards Sustainable Development Goal target 3.4. The Lancet, 392(10152), 1072–1088. https://doi.org/10.1016/S0140-6736(18)31992-5

2. Lu, M., Flanagan, J. U., Langley, R. J., Hay, M. P., & Perry, J. K. (2019). Targeting growth hormone function: strategies and therapeutic applications. Signal Transduction and Targeted Therapy, 4(1), 3. https://doi.org/10.1038/s41392-019-0036-y

3. Vijayakumar, A., Novosyadlyy, R., Wu, Y., Yakar, S., & LeRoith, D. (2010). Biological effects of growth hormone on carbohydrate and lipid metabolism. Growth Hormone & IGF Research, 20(1), 1–7. https://doi.org/10.1016/j.ghir.2009.09.002

4. Vught, A. J. A. H. van, Nieuwenhuizen, A. G., Veldhorst, M. A. B., Brummer, R. J. M., & Westerterp-Plantenga, M. S. (2010). The Effects of Protein Ingestion on GH Concentrations in Visceral Obesity. Hormone and Metabolic Research, 42(10), 740–745. https://doi.org/10.1055/s-0030-1255090