4 Feb 2023
Eben van Tonder

Introduction

Over the last few weeks, I delved into the mechanism of breaking down proteins into amino acids and the problem that can be created through amines if we consume food where the amino acids have been broken down further into these smaller units. Our body uses the amino acids to build proteins and thus repair itself. Protein is thus the key to understanding nutrition. It’s not the full picture of human nutrition, but it is where every discussion on the subject should start. But, our body’s ability to perform these functions is not unique. The ability to produce new proteins and store fat are traits we share with other animals, but the exact way that it does it is different reflecting adaptations to various evolutionary pressures and dietary needs.

Let’s look into this for a moment. It will clue us in as to the importance of proteins in our diet and I will show how even animals who eat only grass cannot survive without proteins. As far as fat storage is concerned, it shows why we all have such a struggle against obesity in a society of abundance from a food perspective.

Protein Synthesis for Repair

-> Humans

Let’s first look at the human body.

– The human body repairs and builds tissues through protein synthesis, using amino acids obtained from dietary proteins. This process is crucial for muscle repair, immune function, and general maintenance of tissues.

– Humans require a balance of essential amino acids, which must be obtained from the diet, as the body cannot synthesize them.

-> Other Animals

How about other animals?

– Most animals have similar mechanisms for tissue repair and growth through protein synthesis. The requirement for essential amino acids is common across many species, although the specific amino acids considered essential can vary.

– Certain animals, like carnivores, obtain all necessary amino acids easily through their meat-based diet. Herbivores and omnivores, like cows and pigs, may need to consume a variety of plant sources to meet their amino acid requirements. Remarkably, the source of proteins for cows originates from the abundant bacteria residing in their rumen, a specialized compartment of their stomach. These microorganisms synthesize amino acids, which the cow then converts into proteins. This demonstrates the complexity of dietary needs in animals, illustrating that even those consuming a plant-based diet indirectly rely on proteins. It highlights the misconception that animals can thrive on a purely plant diet without incorporating protein, emphasizing the crucial role of microbial synthesis in meeting the protein requirements of herbivores like cows.

Fat Storage

-> Humans

We again look at humans first.

– Humans are particularly adept at storing fat due to both evolutionary adaptations to periods of food scarcity and mechanisms to support energy-intensive brain development. This is the basis for the obesity epidemic in an environment where there is no food scarcity.

– Fat storage in humans serves multiple purposes: energy reserve, insulation, and protection of vital organs, as well as playing roles in hormone production and regulation.

-> Other Animals

Other animals use the same, but the storage and rate is not the same as humans. For example:

– Hibernating animals like bears store large amounts of fat to survive winters without eating.

– Marine mammals, such as seals and whales, have thick blubber layers for insulation in cold waters.

– Camels store fat in their humps as an energy reserve, which can be metabolized into water and energy, crucial for survival in desert conditions.

– The ability to store fat and the metabolic pathways involved are conserved across many species, but the extent and physiological roles of fat storage reflect specific ecological niches and lifestyle demands.

Conclusion

The fundamental processes of protein synthesis for repair and fat storage for energy are common across many forms of life. It is a basic biological need for growth, repair, and energy management across many species. However, the efficiency, regulation, and specific roles of these processes can differ significantly between humans and other animals, often as adaptations to different environmental challenges and dietary habits. Our own capacity for extensive fat storage, alongside our dietary flexibility and the need for a balanced intake of essential amino acids, highlights a complex interplay between diet, metabolism, and survival strategies that have evolved over millennia. Our struggle against over-weight is a battle against our past!

References

• Pond, C. M. (1998). “The Fats of Life”. Cambridge University Press.
• Speakman, J. R. (2008). “The physiological costs of reproduction in small mammals”. Philosophical Transactions of the Royal Society B: Biological Sciences, 363(1490), 375-398.
• Spalding, K. L., Arner, E., Westermark, P. O., Bernard, S., Buchholz, B. A., Bergmann, O., … & Arner, P. (2008). “Dynamics of fat cell turnover in humans”. Nature, 453(7196), 783-787.
• Ulijaszek, S. J., Mann, N., & Elton, S. (2012). “Evolving Human Nutrition: Implications for Public Health”. Cambridge University Press.
• Wolfe, R. R. (2015). “Branched-chain amino acids and muscle protein synthesis in humans: Myth or reality?”. Journal of the International Society of Sports Nutrition, 14(1).
• Wu, G. (2009). “Amino acids: Metabolism, functions, and nutrition”. Amino Acids, 37(1), 1-17.