Protein
Protein is of tremendous importance to humans.
Wherever your interest lies—longevity, body composition, skin health, gut health, fertility, cognition, immune function, blood sugar—protein plays a critical role.
Here’s the thing—most of us are under-consuming protein by a considerable margin.
And this is especially true for those on plant-based diets.
Source [1]
Consequences of protein malnutrition
In poor regions, where people do not have reliable access to protein-rich foods, protein malnutrition is a major problem.
Cheap calories from grains might fill a hungry belly, but they are largely devoid of essential nutrients, like protein, fat, vitamins and minerals.
Photo of a young boy with kwashiorkor—a disease of severe protein malnutrition. Note the swelling in the feet and belly. Severe lack of protein, and the accompanying micronutrients, causes hunger, fatigue, low muscle mass, low bone density, immune suppression, and various growth / developmental issues [2,3].
Source: CDC
Even the rich are under-consuming protein
People in richer countries have access protein-rich foods, but our dietary guidelines have funnelled us towards low-protein diets.
1) The Recommended Daily Intake (RDI) for protein is misinterpreted by healthcare professionals / general population
People often misinterpret the protein RDI as meaning ‘the optimal amount of protein to be consumed daily, which should not be exceeded’ [4]. In reality, the official RDI (0.8g / kg of bodyweight) is based on the minimum amount needed to avoid diseases, like kwashiorkor, but does not represent the optimal amount needed by humans [4].
Humans need a LOT more protein than the RDI suggests.
2) Topic of protein quality is being swept under the rug
Animal proteins are higher-quality because they are complete proteins—they provide the entire set of amino acids (AAs) that human physiology requires—whereas plant proteins do not [3,5]. Additionally, animal proteins are far richer in AAs, especially some very important ones, such as leucine, which play key roles in growth and development [4].
Animal and plant proteins are not equal in value.
3) Plant-based dietary guidelines result in similar diets for rich and poor alike
Over the past 100 years, corrupt dietary guidelines have pushed us away from our protein and fat-rich, nutrient-dense ancestral diet, towards an artificial, plant-based one. Carbohydrate-rich foods—especially grains and starchy vegetables—now dominate the diet in poor and rich nations alike.
Again, a surplus of these foods may prevent hunger, but not malnutrition.
Growth, lean mass & metabolic health
Stunting, or growth failure, affects > 100 million of children worldwide, and as we’ve seen, one major cause is protein malnutrition [5,6].
Sarcopenia (low muscle mass and strength), and osteoporosis (weak, porous bones) are common chronic diseases that predominantly affect elderly populations. This physical degeneration is partly caused by sedentary behaviour, but nutrition has emerged as another primary driver [7,8].
Consuming sufficient (animal) protein can help prevent the typical age-associated loss of bone and muscle mass, and muscle strength [4,9].
This is because eating (at least 30g per meal) of animal protein triggers an anabolic / growth response that instructs the body to build and preserve tissues, such as muscle and bone [4,9].
This is essential for normal growth and development in children [7]. It also helps to prevent many age-related diseases, such as sarcopenia, osteoporosis, and even type-2 diabetes [4].
Having a strong skeleton and functional musculature is not some vain fitness project—it’s critical to our quality of life, for young and old, rich and poor.
Essential micros are embedded within essential macros
Animal protein contains a variety of essential micronutrients.
B vitamins
Creatine, carnosine, carnitine…
Zinc, iron, magnesium, potassium…
In plant foods, many of these crucial micronutrients are nowhere to be found, and others have poor bioavailability.
Vitamin B12 is found exclusively in animal foods, which explains why B12 deficiency is common in vegetarians and vegans [10,11]. Vitamin B12 deficiency leads to neurological conditions, anaemia, and in children, growth and developmental issues [12].
Iron and zinc are two essential minerals that people falsely presume to be getting from plant foods, like spinach leaves, or legumes. On paper, such plant foods do appear to be good sources of micronutrients. But in practice—in humans—the bioavailability / absorption of these nutrients is extremely low, due to the fibre and anti-nutrient content (oxalates, phytates, tannins…) that block digestion and absorption [13,14]. The most bioavailable forms of zinc and iron, respectively, are found exclusively in animal proteins, like oysters and red meat.
Animal protein is a non-negotiable, so too are the unique micronutrients it contains.
How much protein should we eat?
Age, activity level + type + intensity, body fat %, and current health status are some factors that influence our protein needs.
Do your own research, and adjust per your situation, but here’s a rough estimate for a relatively active, healthy person.
Male: 1g —1.2g per pound of body mass
Female: 0.8g — 1g per pound of body mass
Ultimately, for someone eating three meals per day, this means around 30g — 60g of protein per meal.
Recap
— Protein is extremely important for humans, and many of us are under-eating protein by a considerable amount.
— Protein is necessary for optimal growth and development in children, and in adults, can stave off muscle loss, bone loss, strength loss, and help improve blood sugar control.
— Human physiology has a clear preference for animal protein, and we need ~30 g at each meal to trigger an anabolic / growth response.
— During illness, periods of intense physical activity, and with increasing age, our protein needs increase.
— Protein comes along with a variety of critically-important micronutrients, such as B vitamins, and minerals, such as iron, zinc, magnesium and potassium.
— Beef, venison, lamb, pork, chicken, duck, eggs, dairy, and seafood are excellent sources of high-quality protein.
Learn more
References
[1]
Wu, G. (2010). Functional Amino Acids in Growth, Reproduction, and Health. Advances in Nutrition, 1(1), 31–37. https://doi.org/10.3945/an.110.1008
[2]
Cleveland Clinic (2023) Kwashiorkor. https://my.clevelandclinic.org/health/diseases/23099-kwashiorkor
[3]
Schönfeldt, H. C., & Gibson Hall, N. (2012). Dietary protein quality and malnutrition in Africa. British Journal of Nutrition, 108(S2), S69–S76. https://doi.org/10.1017/S0007114512002553
[4]
Phillips, S. M., Paddon-Jones, D., & Layman, D. K. (2020). Optimizing Adult Protein Intake During Catabolic Health Conditions. Advances in Nutrition, 11(4), S1058–S1069. https://doi.org/10.1093/advances/nmaa047
[5]
Parikh et al. (2022). Animal source foods, rich in essential amino acids, are important for linear growth and development of young children in low‐ and middle‐income countries. Maternal & Child Nutrition, 18(1). https://doi.org/10.1111/mcn.13264
[6]
Semba et al (2016). Perspective: The Potential Role of Essential Amino Acids and the Mechanistic Target of Rapamycin Complex 1 (mTORC1) Pathway in the Pathogenesis of Child Stunting. Advances in Nutrition, 7(5), 853–865. https://doi.org/10.3945/an.116.013276
[7]
Reid-McCann et al. (2022). The effect of animal versus plant protein on muscle mass, muscle strength, physical performance and sarcopenia in adults: Protocol for a systematic review. Systematic Reviews, 11(1), 64. https://doi.org/10.1186/s13643-022-01951-2
[8]
Arentson-Lantz, E. J., Layman, D. K., Leidy, H. J., Campbell, W. W., & Phillips, S. M. (2023). Important Concepts in Protein Nutrition, Aging, and Skeletal Muscle: Honoring Dr Douglas Paddon-Jones (1969–2021) by Highlighting His Research Contributions. The Journal of Nutrition, 153(3), 615–621. https://doi.org/10.1016/j.tjnut.2023.01.011
[9]
Chen, J., & Long, F. (2018). MTOR signaling in skeletal development and disease. Bone Research, 6(1), 1. https://doi.org/10.1038/s41413-017-0004-5
[10]
Allen, L. H. (2008). Causes of Vitamin B 12 and Folate Deficiency. Food and Nutrition Bulletin, 29(2_suppl1), S20–S34. https://doi.org/10.1177/15648265080292S105
[11]
Green, R., Allen, L. H., Bjørke-Monsen, A.-L., Brito, A., Guéant, J.-L., Miller, J. W., Molloy, A. M., Nexo, E., Stabler, S., Toh, B.-H., Ueland, P. M., & Yajnik, C. (2017). Vitamin B12 deficiency. Nature Reviews Disease Primers, 3(1), 17040. https://doi.org/10.1038/nrdp.2017.40
[12]
Stabler, S. P., & Allen, R. H. (2004). Vitamin B12 deficiency as a worldwide problem. Annual Review of Nutrition, 24(1), 299–326. https://doi.org/10.1146/annurev.nutr.24.012003.132440
[13]
Sandberg, A.-S. (2002). Bioavailability of minerals in legumes. British Journal of Nutrition, 88(S3), 281–285. https://doi.org/10.1079/BJN/2002718
[14]
Solomons, N. W., & Jacob, R. A. (1981). Studies on the bioavailability of zinc in humans: Effects of heme and nonheme iron on the absorption of zinc. The American Journal of Clinical Nutrition, 34(4), 475–482. https://doi.org/10.1093/ajcn/34.4.475