John Yudkin, Linus Pauling and the Sugar Question

“In my book I say you shouldn’t eat sweet desserts, but I also quote a professor who says that this doesn’t mean that if your hostess has made this wonderful dessert you should turn it down.  My wife used to say I always looked for that hostess.”

-Linus Pauling, 1987.

Linus Pauling and John Yudkin shared a semisweet bond that was nearly equal parts contradiction, respect and humor, and which lasted from the mid-1970s until Pauling’s death in 1994. The two men held radically different views on a number of topics including the effects of vitamins, especially vitamin C, but shared an identical view on the dangers of sugar. Indeed, Yudkin’s claims in his 1976 book This Nutrition Business that Pauling’s beliefs about vitamin C were completely incorrect did not deter Pauling from citing Yudkin’s work on sugar in a favorable light in How to Live Longer and Feel Better, published ten years later.

John Yudkin was born in London in 1910, earned a degree in chemistry and a Ph. D in biochemistry, and later studied medicine in London. As the Chair of Physiology at London University at Queen Elizabeth College, he persuaded the university to institute a Department of Nutrition in 1954, the first department in Europe devoted to undergraduate and postgraduate teaching and research in nutrition. In 1954 Yudkin became the Chair of Nutrition for Queen Elizabeth College. In the 1960s, he grew increasingly concerned with the role of nutrition in western afflictions like obesity and diabetes, and spoke of the problem of “the malnutrition of affluence.” Yudkin retired from Queen Elizabeth College in 1971, and became Emeritus Professor of Nutrition.

Pauling first commented on Yudkin’s work – chiefly his book Sugar: Sweet and Dangerous – in a 1972 article for the newsletter Executive Health. In it, Pauling summarized Yudkin’s belief that sugar is an important cause of coronary heart disease, and that saturated fat and cholesterol are not. He also described a study carried out by Yudkin in 1957, in which the death rate from coronary disease in fifteen countries was correlated in relation to the average intake of sugar. The study concluded that men consuming relatively large amounts of sucrose faced far greater odds of developing heart disease in the age range of 45 to 65, than did those who did not ingest as much sucrose. Pauling agreed with Yudkin’s findings that sugar not only provided “empty calories,” but also contributed to various diseases.

In 1976 Pauling received a copy of Chapter 12 of Yudkin’s book, This Nutrition Business, in the mail.  In this chapter, titled “What You Can Expect from Vitamins,” Yudkin stated that Pauling’s claims about vitamin C were untrue. Yudkin suggested that the human body needs a certain amount of vitamins and no more, and that to ingest more vitamins than are required is a waste – thinking that was common at the time. He added that he knew Pauling personally and thought of him as warm and friendly, but also that “I think sincerely that he is wrong in most of what he says about vitamin C and about the use in large amounts of this and other vitamins in the preservation of health and in the treatment of disease.”

He then proceeded to find fault in Pauling’s argument that the best diet is one of raw fruits and vegetables; a diet that would provide roughly the same amounts of vitamin C that humans consumed millions of years ago. Yudkin instead argued that humans have subsisted on an omnivorous diet for at least two million years, and that if they really weren’t ingesting enough vitamin C they would have died off long ago.

The year after Yudkin wrote about Pauling in his book, Pauling – in what may have been a retaliation of sorts – singled out Yudkin as an example of subjective reporting on nutrition.  Pauling mailed his editorial “Needed: More Responsibility, More Objectivity, Less Bias,” to Yudkin along with a short note telling him that he was sorry to have to use him as an example, and that he hoped Yudkin would “get around to examining the evidence about nutrition in relation to disease in an unbiased and responsible way sooner or later.” Yudkin answered Pauling with a terse note informing him that his views were simply different, and that Pauling should not accuse people of being biased and irresponsible just because they had differences of opinion.

It was clear by 1986 that all was forgiven, when Pauling cited Yudkin extensively in his book How to Live Longer and Feel Better.  In Chapter 6, Pauling discussed Yudkin’s book Sugar: Sweet and Dangerous, in which Yudkin demonstrated that ingesting sucrose leads to coronary disease. According to Pauling,

Against the general public acceptance of the proposition that coronary heart disease is caused by a high intake of animal fat (saturated fat) and the eating of foods containing cholesterol, Yudkin himself has shown that for some countries the correlation of coronary disease with intake of sugar is much better than that with intake of fat.

Pauling later commented that “It has been shown in a trustworthy clinical study that the ingestion of sucrose leads to an increase in the cholesterol concentration in the blood.” The trustworthy study of which he speaks was reported by Milton Winitz along with his associates in 1964 and 1970. This investigation studied eighteen prisoners who had volunteered to be locked into an institution for about six months and have their cholesterol levels recorded as they were fed a specific diet. After a preliminary period, the group was placed on a small-molecule diet made up of seventeen amino acids, a little fat, vitamins, essential minerals, and glucose.  From there, more sucrose was added back into the diet.  During the length of the study, the group’s cholesterol levels were closely monitored.

The average cholesterol concentration during the initial period, during which the subjects had been fed a standard Western diet, had been 227 milligrams per deciliter. After two weeks on the glucose diet, the average concentration dropped to 173 and, two weeks later, to 160. After that point, a quarter of the glucose in the subjects’ diet was replaced by sucrose. In a week the average cholesterol concentration was 178, and two weeks later it had risen to 208. The glucose was then added back into the diet, replacing the sucrose, and results were evident in one week, when the average cholesterol concentration dropped to 175, and kept dropping afterward to points even lower than the 160 initially recorded. In his book, Pauling stated that this study “shows conclusively that an increased intake of sucrose leads to an increased level of blood cholesterol.”

At the end of Chapter 6, Pauling concurs with Yudkin and gives advice to the reader regarding sugar. His first admonition is to keep away from the sugar bowl – to keep it out of your coffee or tea. He also warns against prepared, frosted breakfast cereals, and to keep away from any regular intake of sweet desserts. His last piece of advice is to avoid soft drinks. In a different section of the book, Pauling advises, as part of a regimen for better health, to “keep your intake of ordinary sugar (sucrose, raw sugar, brown sugar, honey) to 50 pounds per year, which is half the present U.S. average.” (By 2003, Americans were consuming 142 pounds per year, on average.)

In December 1987, Pauling was interviewed for the magazine Outside for an article that focused specifically on his views on sugar. In it, Pauling is quoted as saying, “the increasing incidence of [coronary] disease closely parallels the increasing consumption of sugar. It is not at all correlated with the consumption of animal fat (saturated fat) or of total fat.” With this, Pauling reaffirmed his support for Yudkin’s viewpoint that sucrose is the primary culprit behind cardiovascular disease.

In 1989 Yudkin visited Pauling in person and, shortly thereafter, sent to Pauling a copy of his latest book Pure, White and Deadly. In thanking Yudkin for the book, Pauling asked if he would be willing to serves as a member of the Board of Associates of the Linus Pauling Institute of Science and Medicine. He also asked for a biographical sketch to be run in the Institute’s newsletter, and likewise asked for permission to reprint parts of the book in the publication.

Yudkin eventually agreed to join the Board of Associates (once assured by Pauling that his joining would not involve any work, since he had too much already) and provided a biographical sketch along with a letter in which he joked that he had “excluded such interesting aspects of my life as what clothes I wear, what I have for breakfast…”  Little bits of humor such as these dot the correspondence between the two men, who maintained a friendly relationship despite their occasional public disputes.

In a memo relaying news of Yudkin’s appointment to the Board, Pauling noted that “[i]t was Yudkin’s work that caused me to make my strong recommendations about decreasing the intake of sucrose.” Pauling also obtained copies of Pure, White and Deadly to distribute to members of the Institute, and continued to promote the book in the LPISM newsletter. Clearly, although Yudkin contradicted Pauling’s strong arguments in support of vitamin C, Pauling saw the logic in Yudkin’s case against sugar and stood firmly behind it.