Protein in vegan diets
Intro #
This is an excerpt from a tiny newsletter that I used to send to friends when I was intensely learning about climate change. In this issue, I was trying to learn about the impact of vegan diet on health. The largest worry that many people have when they stop eating animal products is that they do not get enough protein, or that the protein they get from plants is somehow less digestible than what they could get from animals.
It turns out that people in the Global North have an obsession with protein intake, and most of us eat too much of it. This obsession originates from low-quality research into malnutrition in developing countries at the beginning of the 20th century. When we look at actual data, most people on a vegan diet get enough protein, and experience no negative health effects. I link to two relevant papers below. Enjoy!
Papers #
"The great protein fiasco" and "The Great Protein Fiasco Revisited" by McLaren - Examines the origins of our obsession with protein intake. It's all because of Kwashiorkor. Kwashiorkor happens when you don't consume enough of certain aminoacids (even though you get enough calories in general). This was found to be the case in children in some parts of rural Africa in the 1930's. Some people thought that was really clever, so they generalised the finding to the general problem of childhood malnutrition. This gave birth to an entire industry of protein supplementation, which provided a useful dumping ground for US dairy and chemical companies. In reality, most children simply weren't getting enough calories.
"Dietary Protein and Amino Acids in Vegetarian Diets — A Review" by Mariotti and Gardner - I often get asked 'where I get my protein from', but somehow my lacto-ovo-vegetarian friends don't. Vegans get ~13% of their energy from proteins. Lacto-ovo-vegetarians - 14% (it's 17% for meat-eaters). This is more than enough. The protein intake in rich countries has risen about 30% over the past 50 years, to the point where the average person consumes almost double the estimated average requirement. Some vegans (10-15% of males, 5% of females) seem to have lower-than-recommended protein intake, but this is a similar figure to the amount of vegans who do not get enough calories in general. Mariotti & Gardner also look at two other common myths about vegan diets:
- That plant proteins do not have an optimal amino-acid profile. They do, so long as you mix them up and don't eat only rice or only beans.
- That plant proteins are less digestible. In fact, for uncooked plant proteins, people absorbed 89–92% of protein content, similarly to eggs (91%) and meat (90–94%).
One of the authors of this study is a lead research with the French association for the promotion of plant protein, so take the above with a grain of salt.