Bioavailability and micronutrient suitability of protein sources.

Executive summary

Consumers are becoming more aware of the impacts of their food choices on their health and on the environment. Many people believe that animal source foods are detrimental to both of these factors, whilst consuming only plant source foods will alleviate these problems. In the age of technology, misinformation and disinformation are easy to access and the health and nutrition sectors are not immune from this problem.

However, the notion that global health and environmental problems will be fixed by simply eliminating a particular food group is an overly simplistic view of a complex and dynamic situation. Dispelling misinformation and disinformation is imperative to making informed dietary choices, both on an individual basis but also from a policy making point of view.

The objectives of this report were to investigate the bioavailability of protein and micronutrients from different protein sources, and to evaluate the suitability of plants source foods to provide adequate levels of protein and micronutrients to support optimal human health. A review of literature was conducted in conjunction with an interview of a leading scientist in human protein nutrition to analyse the role of protein in dietary choices. This allowed me to draw key themes, apply critical thinking to research and themes, and identify areas of crucial importance.

The gastrointestinal tract and physiology of the human body differs from herbivorous mammals; humans are not able to synthesise the entire range of amino acids and micronutrients endogenously. These amino acids and micronutrients must then be sourced from the diet to ensure optimal health.

Protein quality is characterised by the amino acid profile of the protein, and the ability for this amino acid to satisfy the amino acid requirement of the person consuming the protein. Protein quantity in a diet is irrelevant if the protein in the diet is deficient in essential amino acids; amino acid deficiencies can still occur in someone consuming more protein than required if the protein being consumed doesn’t contain sufficient quantities of the most limiting amino acid in the diet.

The ability for nutritional and medical researchers to study human nutrition has limitations due to the constraints involved with this nature of research. Large scale research relies on evidence supplied by individuals which can be subjective. Small scale, more detailed research is extremely variable as each person will respond to the same treatment in a different manner, and this is influenced by many physiological factors.

Furthermore, the research is highly invasive, and endogenous biological processes mean that it is often not 100% accurate. Nutritional research using animals also has limitations due to interspecies physiological differences. As a result of these factors, there is strong discord amongst nutritional researchers as to dietary recommendations.

The bioavailability of proteins is defined by the digestibility of the protein, the chemical integrity of the protein and the interference in the metabolism of the protein from other compounds in the food matrix. Research has found animal source proteins to have higher bioavailability than plant source proteins.

Furthermore, animal source proteins are also rich sources of micronutrients, which also have high bioavailability for humans. In plant source foods, whilst they may contain micronutrients important for human health, these micronutrients may not be in a form which can be absorbed and utilised by humans, rendering the micronutrient no use.

Micronutrient deficiencies and amino acid deficiencies are widespread in populations who rely on staple based diets. These diets are confined to a small range of nutrients due to geographical and financial constraints. The incorporation of animal source proteins in these diets would aid in alleviating malnutrition amongst these populations by providing both high quality proteins and a wide range of bioavailable micronutrients.


  • Advocate for scientific verification when policy is created with respect to restrictions on food groups.
  • Invest into food security and agricultural sustainability in third world countries to allow them to be self-sufficient and free from malnutrition.
  • Understand the research accurately to ensure confounding factors don’t influence interpretation of nutritional research.
  • Reduce restrictions on productivity to ensure malnourishment and food scarcity doesn’t worsen in vulnerable populations due to policy decisions in wealthy countries.
  • Identify limitations in a diet where food groups are eliminated.
  • Advocate for accuracy on food labelling to inform consumers of true nutritional value of foods.
  • Take ownership of the promotion the wholesome benefits of our products.
  • Ensure perceived environmental benefits of dietary choices are accurate.

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