Protein Myth
Myths about protein, especially animal protein.
Summary from Chapter 5 of The Future of Nutrition
History
In 1839, a group of researchers discovered that if dogs were continually fed food lacking a certain element, they would die. Aside from oxygen, this was said to be the first case of discovering such a substance. This led to the birth of the concept of essential nutrients. Because it was regarded as a truly important substance, it was given the name “protein,” derived from the Greek word “proteios,” meaning “of prime importance.”
The Dutch organic chemist Gerard Mulder (1802-1880) said this about protein:
There is no doubt that it is the most important substance among the organic substances known so far. Without protein, no life on Earth could exist. It is through protein that the phenomena of life can appear.
Justus von Liebig (1803-1873), called the father of German organic chemistry, described protein as “the very stuff of life.”
Forty years later, one of his roughly 700 disciples, Carl von Voit(1831-1908), repeated his teacher’s words verbatim and recommended protein consumption. He is called the father of nutrition. He discovered that about 52g of protein per day was sufficient, but without much basis he insisted that one should consume 118g, nearly double that amount. Seven of his colleagues were similar, with their recommended amounts ranging from 100–134g per day. And of course, when the authorities of the time spoke of protein, they naturally meant animal protein.
Max Rubner(1854-1932), famous for his research on energy metabolism and the person who coined the word calorie, was one of Voit’s students. He claimed that protein was “interchange of civilization” itself. According to another record, Major McKay, a British medical adviser, liked the Bengali people of India because they preferred more protein than other groups.
He also claimed that “inferior” races did not eat enough protein. H. H. Mitchell, a prominent American nutrition researcher, said the same thing. Mitchell is the person who developed the standard calculation method for determining the nutritional value of animal protein.
The influence of these early researchers had a tremendous impact on the field for a long time afterward. For example, W. O. Atwater(1844-1907), another student of Carl von Voit, established the first nutrition program at the USDA, and that program still influences the advisory committee for the American dietary guidelines more than 100 years later.
If self-correction could take place, this lineage of early researchers might not itself be much of a problem. But the field of nutrition is famous for changing only with difficulty. Even after World War II, USDA nutritionists were still praising protein, especially animal protein. The content of the “basic seven food groups” proposed in 1943 has not changed very much to this day.
Measuring Animal Protein: the “High Quality” Smokescreen
The apostles of animal protein often assert that animal protein is of better “quality” than plant protein. To trace the origin of this belief, we need to look at how the discussion of quality began in the first place. Soon after the discovery of protein, scientists began searching for an objective method to measure the relative value of protein. This was a rational and understandable goal, but it eventually became established in a deeply flawed form.
The first method attempted was the Protein efficiecy ratio (PER). A food’s PER was measured by weight gain relative to protein intake. In other words, it was a way of measuring the degree to which protein promotes bodily growth. This method was mainly applied to livestock rather than humans (for the sake of maximizing profit), and has nothing to do with human health.
The more widely used measurement method throughout the 20th century was biological value (BV). It was devised in 1924 by H. H. Mitchell, a professor of animal science at the University of Illinois. It measures retained nitrogen in the body after protein intake to see how efficiently the protein was used, but there was no basis then or now for the claim that protein efficiency can be measured through nitrogen.
Mitchell’s bias toward animal protein was strong. Like Major McKay before him, he considered people who did not eat enough protein to be inferior races. BV, like PER, is a method that is hardly mentioned directly in modern times, but I introduced it here for the sake of explaining the historical context.
More recently, a calculation method called amino acid score (AAS) was developed. It evaluates how closely a protein’s amino acid composition matches the proportions required by the human body. If one were to take this method seriously, the highest-quality protein would be obtainable from human flesh. There are other calculation methods such as the protein digestibility-corrected amino acid score (PDCAAS), but all of them are based on the assumption that “if efficiency is high, quality is good.” Since one cannot assume that amino acids are always used by the body only in beneficial ways, all such approaches to quality lack much scientific basis.
Moreover, it is important that when consuming animal protein, one also consumes numerous other components along with the protein, such as cholesterol and saturated fat. One must not consider only protein or amino acids; one must also consider the overall and broader effects together.
Moreover, even the effects regarded as the advantages of animal protein are misleading. Even if “high-quality protein” promotes the growth of young children, there is not much evidence that physical development in childhood affects adult height or build. Except in cases of certain diseases during childhood, height is more strongly influenced by genetics.
Also, intake of “high-quality” animal protein leads to an increase in growth hormone, which in turn leads to more sex hormones and earlier development of secondary sexual characteristics. And this is one of the causes that increases the incidence of cancer in the reproductive organs. Such side effects of animal protein have not been sufficiently made known to the public. According to experiments the author conducted on rats in the 1970s and 1980s, when they were fed large amounts of milk-based casein protein, the growth hormone associated with cancer occurrence increased greatly. By contrast, when they were fed large amounts of wheat protein, a so-called “low-quality protein,” cancer occurrence was suppressed instead, because wheat protein lacks lysine. When lysine was added back in, cancer growth returned to the same level as with casein.
Animal-Protein-Centered Language
People calling themselves ‘health experts’ repeatedly use the phrase, “animal protein is high quality.” But quantification itself cannot be called bad. For example, BV is a useful enough indicator in its own way. The problem is only that people misinterpret it as though a high BV is good and a low BV is bad. Such misreadings often stem from animal-protein-centered language.
For example, the International Agency for Research on Cancer (IARC) says that red meat is a carcinogen, while at the same time saying that it contains protein with high biological value. But it has long been well known that the same nutrients can be obtained without red meat. If the “biological value” of some food is high, shouldn’t it have the effect of preventing cancer or helping treat it? This kind of double message is observed very frequently.
If it is carcinogenic and has all sorts of side effects, how can one call it ‘high quality’? “High-quality animal protein” is nothing more than a myth.
Animal-Protein-Centered Policy: Feeding the World?
(Omitted)
Erased Prior Research
Why does a myth from the 19th century still persist? Why were there no people who pointed out the error? In fact, besides the author, there were many such people. They have simply continued to be forgotten.
Russell Chittenden(1856-1943), a professor at Yale and a member of the National Academy of Sciences, was one of them. He argued that not only were 20–40g of protein per day sufficient, rather than the 100–134g proposed by Carl von Voit and his colleagues, but that consuming only that much was actually better for health.
Another Yale professor, Irving Fisher1, conducted a similar experiment with athletes and reached the same conclusion. The records of the group that did not eat meat or seafood were overwhelmingly better.
More than a hundred years later, the documentary “The Game Changers” on the same subject was produced, and as of the time of writing this book, about one-third of the NFL players on the Tennessee Titans are following a whole-food plant-based diet, and professional golfer Gary Player, Olympic medalist wrestler Chris Campbell, and others are on a whole-food plant-based diet while still achieving world-class results. Even so, almost no nutrition researchers know Chittenden’s or Fisher’s research.
Group thinking: The Invisible Fence
(Omitted)
The False Dichotomy of Complete and Incomplete Protein
Most protein-containing food ingredients we eat are complete proteins, so the complete-incomplete distinction is not very meaningful. Especially considering that the only incomplete protein is the animal protein gelatin, the distinction that animal proteins are complete proteins and plant proteins are incomplete proteins is a fabrication.
Reference: complete protein