Proteins are essential for numerous vital functions, ranging from tissue construction to the regulation of the majority of biochemical processes in our bodies. Unfortunately, a significant portion of the population does not consume an adequate amount of proteins in their daily diet, which can lead to deficiencies in essential amino acids, the basic building blocks of proteins.
The populations particularly affected by this problem are those considered vulnerable: children, pregnant or breastfeeding women, and individuals over 65 years of age. In fact, scientific evidence shows that these groups have increased protein needs, even though they are often the ones who consume the least.
Protein deficiency results in an insufficient supply of amino acids, as they cannot be stored by the body. They are immediately used for various essential functions, including tissue building (muscles, skin, hair, nails), nutrient transport, hormonal regulation, the immune system, brain neurotransmitters, blood pH regulation, metabolic processes, and the modulation of gene expression through DNA methylation.
Amino acids: the foundations of our body
Amino acids are the foundations of our body, playing a central role in protein synthesis. The amino acids we obtain through our protein consumption are used to create our own proteins.
Among the 20 existing amino acids, nine, such as histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine, are traditionally considered essential for humans. Unlike some bacteria or plants, mammals, including humans, can only produce 11 of them. Therefore, they must obtain the other nine through their diet.
However, studies challenge this classification between essential and non-essential amino acids. They indicate that even non-essential amino acids must be provided in sufficient quantities through our diet because there is no convincing evidence that our body synthesizes them adequately for proper long-term function.
How much protein should we consume?
The World Health Organisation (WHO) has maintained its recommendations for daily protein intake for adults at 0.8 grams per kilogram of body weight per day (g/kg/day) since 2007. However, over the past decade, many studies have shown that these recommendations underestimated protein and amino acid needs of individuals. Furthermore, these recommendations did not take into account crucial factors such as the level of physical activity and the presence of comorbidities, such as chronic kidney disease.
According to global experts, an appropriate daily protein intake for sedentary adults aged 25 to 65 should be between 0.9 and 1.0 grams per kilogram of body weight. However, this range varies considerably depending on vulnerable populations and physical activity levels.
For example, adults over 65, provided they do not have kidney problems, should aim for a range of 0.9 to 1.3g/kg/day to prevent muscle wasting leading to conditions like sarcopenia.
The protein needs of pregnant women gradually increase during pregnancy as the fetus develops, ranging from 1.2 to 1.5 g/kg/day.
Finally, individuals engaged in significant physical activity may require intake ranging from 1.8 to 2.6 g/kg/day, depending on the intensity, frequency, and type of physical activity (endurance or strength/muscle hypertrophy).
So, we are far from the WHO’s recommended dietary allowances (RDAs) from 2007.
Not all proteins are equal
Finally, it’s worth noting that not all proteins are of equal quality and bioavailability. Animal proteins found in meat, fish, eggs, and dairy products are considered high-quality because they are complete in essential amino acids and are better absorbed due to their composition. In contrast, plant proteins found in legumes, soy-based products, nuts, edible seeds (sunflower, flax, etc.) and, to a lesser extent, grains, have a less complete amino acid profile, affecting their digestion and absorption (Table 1). However, they are essential in vegetarian and vegan diets and can complement protein needs in an omnivorous diet.
Fundamental for our bodies, insufficient protein consumption and the resulting amino acid deficiency are likely the cause of many disorders and diseases, even though this connection is often overlooked.
By Dr Aurélien Núñez
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Aurélien Nuñez is a Functional and micronutritional Medical Doctor, graduated from the Favaloro University of Buenos Aires, Argentina. Specialised in Micronutrition, Food, Prevention and Health (MAPS) from the Paris Descartes University. He is working at Hotel Capela Das Artes in a project named Smart Treatments, where with his colleague, Silvestre Gonzalez, an Ayurveda-oriented Medical Doctor, and a team of therapists, are offering consultations, body therapies, retreats, yoga, meditation classes and workshops.