WAS SUGAR REPORT TOO SOUR?
1960s DOCUMENTS Rat research pointing to cancer quashed: report
The sugar industry abruptly terminated funding for a study that suggested a possible link between sugar and bladder cancer nearly 50 years ago, according to a new review of industry documents.
The rat study — known as “Project 259” — was finding that the urine of rodents fed a high-sucrose (versus highstarch) diet contained higher levels of an enzyme that had been previously associated with bladder cancer in rats, according to the authors of the latest analysis of “the sugar papers” — a cache of internal memos, letters and company reports unearthed by University of California at San Francisco researchers.
Project 259 also suggested a possible mechanism for how gut bacteria metabolize sugar to drive up triglycerides, a type of fat circulating in the blood that increases the risk of heart disease, the researchers report.
But the results of Project 259 were never published. After dismissing the study’s value as “nil,” the International Sugar Research Foundation put an end to its funding, according to the new analysis, published this week in the journal PLOS Biology.
“Let’s say this study had been going the other way and you could have fed these animals massive amounts of sugar and it didn’t do anything,” co-author Stanton Glantz, a professor in the division of cardiology at UCSF, said in an interview. “I’m sure (the sugar industry) would not have cut off the funding. They would be out there thumping the tub — ‘look, we fed these rats, like, five gazillion pounds of sugar and it didn’t matter.’ ”
In a statement, The Sugar Association called the new paper “a collection of speculations and assumptions about events that happened nearly five decades ago,” written and funded by “known critics of the sugar industry.” It said the study was nixed not because of “potential research findings,” but because it was behind schedule and over budget.
“There were plans to continue the study with funding from the British Nutrition foundation, but, for reasons unbeknown to us, this did not occur.”
Association president and CEO Courtney Gaine said she could find nothing in a search of the archived project reports about a possible link with bladder cancer. Last year, The Sugar Association issued a news release downplaying results of a University of Texas mouse study linking sugar to cancer, saying, “no credible link between ingested sugars and cancer has been established.”
The new analysis, however, suggests the industry cut off funding because the animal study was teasing out a possible link.
“The kind of manipulation of research is similar (to) what the tobacco industry does,” Glantz alleged in a statement released with the study.
In an earlier analysis of the sugar papers published last year, the UCSF team reported that the industry bankrolled a review article published in 1967 by Harvard scientists that downplayed sugar’s role in heart disease — in part by pointing the finger squarely at saturated fat.
Researchers report that the next year, what was then known as the Sugar Research Foundation launched Project 259 in rats. This time, they chose Walter Pover, a biochemist at the University of Birmingham who was paid roughly US$188,000 in today’s dollars to lead the study between 1968 and 1970.
Pover set out to test the effects of different carbohydrates on triglycerides in two groups of rats — one germfree, the other normal rats with gut bacteria.
In a progress update he gave to his funders in August 1970, Pover reported that the results, so far obtained, “seem very interesting indeed.” When germ-free rats were fed sugar, their triglyceride levels didn’t rise. The results suggested that triglycerides form when microbes in our gut ferment sucrose, said first author Cristin Kearns, a finding Pover reported to his funders as “highly significant.”
Rats fed sucrose also showed higher levels of betaglucuronidase, an enzyme Kearns says had previously been associated with bladder cancer in humans. But she and her co-authors cite only two studies, from 1955 and 1968, suggesting an association between elevated levels of the enzymes in urine and bladder cancer.
Pover said he needed 12 more weeks to complete his experiments. Instead, his money was pulled. The Sugar Association said the study had already been extended a year. But Kearns said that, if confirmed, the finding would have bolstered the argument at the time that sucrose increased the risk of heart disease.
The sugar industry “has consistently denied that sucrose has any metabolic effects related to chronic disease beyond its caloric effects,” the authors write in PLOS Biology.
But, how bad is sugar? It’s still hard to say.
In The Case Against Sugar, author Gary Taubes (who, for the new paper, provided funding for Kearns to travel to the Harvard Medical Library) prosecutes sugar as the root cause of the things statistically most likely to kill us, “or at least accelerate our demise, in the 21st century.”
Yet he also acknowledged that the science, as it stands now, hasn’t unequivocally proven sugar to be “uniquely harmful — a toxin that does its damage over the decades. The evidence is not as clear with sugar as it is with tobacco.”