Paradigm Change in Human Nutrition

The Structure of Scientific Revolutions

Thomas Kuhn 1962

Science texts seem to imply that the content of science is uniquely exemplified by observation, laws. and theories.

Science pretends to be a constellation of facts, theories and methods, collected in current texts, .... making an ever-growing stockpile that constitutes scientific technique and knowledge.

However, historians of science, find it difficult to distinguish the science of the past, from myth and superstitious beliefs. Myths are produced by the same sorts of methods, and are believed for the same sorts of reasons, that we attribute to scientific knowledge.

Edit 2022: [Our recent experience with Covid-19 is a good example. While the virus was busy doing what all viruses do, spreading itself, causing infection, and killing many people. Countries with very good medical systems assumed that the virus would be contained and controlled without strong action. That was a mistake. The mistake was compounded in country after country by politicians who didn't understand the situation. They were falsely confident and determined not to close down the economy. They focused on blaming China, and later on finding scapegoats for their own mistakes. Almost everywhere the system failed.]

The early development of any field of science is characterized by a number of competing views, none of which are clearly better, or more important, or more valid than any other view. That's because normal science begins with the assumption that the scientific community knows, and agrees, what the world is like. Without that understanding, without a paradigm, sensible discussion cannot begin.

You can see in the list of historic achievements on the right that there is no direction to these discoveries. They are disjointed. There is also a very long delay between the recognition of some new fact, and it's adoption in practise. The treatment of scurvy is a good example.

Edit 2022: [When Covid-19 became a pandemic, the lack of knowledge, was denied. Blustering confidence was displayed, and promises made. It would have been better to have admitted, that they "Don't Know" and to work cooperatively with the WHO. Instead, nations that could afford it jumped the que by securing vaccines by pre-payment and contractual agreements. The health advice of experts was ignored, in favour of local political objectives.]

Many of the early discoveries were made in caring for livestock. Farmers understood 200 years ago how to make a pig fat. But there was no connection made between fat pigs and fat people. Elmer Verner McCollum began his research with farm animals in 1912. Because cattle have a long life cycle, McCollum chose rats for his experiments. Farmers couldn't see the connection, and McCollum was dismissed. He went on to work at John Hopkins University, still studying rats. In the 1920's he reported that it was possible to have a healthy vegetarian rat, but it was so difficult that he recommended against it. Vegetarian rats usually had stunted growth, had difficulty reproducing, and lived shorter lives. The addition of dairy foods to a rats vegetarian diet, improved the health of the rats considerably. Nobody at the time seriously considered that this observation might ALSO be applied to human nutrition.

McCollum began with a simple idea that if food was palatable animals would eat enough food to be healthy. He went on to discover vitamin A, vitamin B, later many types of vitamin B. He also discovered the link between vitamin D and rickets, and identified many trace elements important to good nutrition.

In regards to human nutrition, there has been a theory of cuisine, cooking schools, home management and home economics, but there was no human dietary recommendation based on good science before 1980. Early research on food and nutrition was random fact gathering. The result was something much less than science. Still this was the base on which later science was built.

By 1910, vitamins were recognised as important, but what were they? Vitamin A and B were identified in 1913. And in 1919 a lack of vitamin D was identified as the cause of rickets.

In 1922 food factor X was identified as essential to the good health of rats. In 1925 it was identified and called vitamin E.

The citric acid cycle was identified in the 1930's but not understood until many years later. Prior to WWII the best nutritional science was done in German and Austrian laboratories, but his work was hardly known in the English speaking world. And after WWII, victors justice ruled, and most things German and Austrian were swept aside (except for rocket research.).

WWII introduced studies into starvation, and into the effect of nutritional restriction on the population. Ancel Keys worked on an ideal diet for soldiers, K rations. Elsie Widdowson and Robert McChance wrote about the chemical composition of foods and the effects of foods, using themselves as experimental subjects. In 1941 they were asked to advise on wartime food rationing.

After WWII the post war boom produced a wave of enthusiasm for better dining. Elmer Verner McCollum was honoured in 1951 as "Dr Vitamin." In 1977 Senator McGovern was very concerned that the American diet rich in red meat and saturated fats and cholesterol was causing heart disease, obesity, diabetes and some forms of cancer.

Senator McGovern employed an assistant, Nick Mottern, a vegetarian who believed that red meat was unhealthy for humans. Mottern wrote the report for Senator McGovern's Committee. This report became "Dietary Goals for Americans," issued in February, 1980. This proposal was eagerly accepted, by doctors, by heart foundations, by nutritionist's and by diabetes associations. The objective now was to get the American public (and the world) to follow the recommendations.

The work of the McGovern Committee attempted to achieve three things, to reduce the risk of heart disease, to provide low cost food for consumption, and to support the income of the American farmer, and to a lesser extent the American food industry.

When the Guidelines for Americans were published, the chief guardian of the recommendations was the United States Department of Agriculture. The Standard American Diet (SAD), which has hardly changed in 40 years, was never a scientific document, it was from the beginning a political document.

The Standard American Diet became the "recommended diet" for most of the world, it was the first widely accepted paradigm about how humans should eat for health. The key principle is that people should eat a mixed diet, a little of everything in moderation, unless higher heart disease risk is indicated. Low fat and low cholesterol foods were advocated, as recommended by Ancel Keys.

Kuhn says that a new paradigm demands:
An achievement sufficiently unprecedented to attract an enduring group of adherents.
Simultaneously, it is sufficiently open-ended to leave all sorts of problems for the group of science practitioners to solve.

The SAD established distinct boundaries around the type of dietary research the US government would support. This developed a new field of nutrition research, but there were very few practitioners. There had been no money in human nutrition.

The new paradigm imposes itself on the field. It determines what good science questions might be, and also what might be considered a valid scientific response. We can now make a list of problems that we should be able to solve, within the rules of the paradigm. Those who accept the rules and adapt themselves to work within this paradigm, can get funding, win support and build careers. The paradigm, defines "the agreed understanding of fact and theory", that is henceforth taken for granted.

Those who choose to work outside the paradigm, must proceed in isolation or attach themselves to some other discipline.

Many researchers understood that Keys was wrong. They include Dr George V. Mann, Jacob Yerushalmy, E.H. Ahrens, Dr John Yudkin, Dr Charlotte Young, and Fred Kummerow, but the mood of the day was running against them. Ancel Keys was being hailed as a national hero. Everyone seemed to agree that poor diet; too much saturated fat, raised cholesterol, clogged the arteries and caused heart disease. Case closed, but the hypothesis had never been tested.

Paradigms gain status because they are more successful than their competitors in solving a few problems that practitioners in the field consider important. Working inside the paradigm is to be scientific. Working outside the paradigm is to cease practice in the science the paradigm defines.

In the 1970's Dr Robert Atkins did battle with the scientific establishment and lost. His diet fell outside the low-fat, low-cholesterol, and high-carbohydrate diet of the new paradigm. Vegetarian diets, were acceptable inside the model. Low-carbohydrate high-fat diets were not.

1970's and 1980's there was significant pushback by the food industry on any scientific publications likely to influence the market. Fred Kummerow, and Mary E Enig both had long running battles with industry. They and many others couldn't get funding for research, and couldn't get papers they had already written published.

Dr Robert Atkins, Stephen Phinney and others, suffered because what they were researching and recommending was outside the accepted model of what a healthy human diet should be.