-- Potential conflicts from industry-sponsored medical research have been an ongoing concern among public health officials, and a new report looks at how undisclosed funding could have had a major impact on medical findings and decades of research that followed.
A report in the Journal of the American Medical Association Internal Medicine reviewed a case from the 1960s when three Harvard researchers were paid by a sugar industry group to do research looking at heart disease and sugar consumption. The paper resulting from that research found "limited" evidence for the link between sugar consumption and heart disease, contradicting previously published studies, according to the JAMA report, published Monday.
The sugar industry "protected their interest for half a century, which points to the importance of truly independent science," study co-author Stanton Glantz told ABC News.
"Industry research tends to publish information that supports their own endeavors," said Glantz, professor of medicine and director for Center of Tobacco Control Research and Education at the University of California, San Francisco.
Three Harvard researchers, now deceased, were paid by a sugar industry group and subsequently published an article in a major medical journal in 1967 examining sugar and its relationship with heart disease, according to the report published Monday. That article found "limited" evidence for the link between sugar consumption and heart disease, contradicting previously published studies.
Glantz and other researchers from the University of California, San Francisco, found correspondence between the Harvard researchers and the sugar industry in the 1960s and realized they had been paid $6,500 -- the equivalent of $48,900 today -- to conduct a review on medical literature focused on sucrose consumption and coronary heart disease.
The Sugar Research Foundation, a trade group, approached Dr. Frederick Stare, then the chair of the Harvard University School of Public Health Nutrition Department, in 1965 to review multiple medical studies examining the relationship between sugar, fat and coronary heart disease, according to the JAMA report. At the time, some published studies had found a link between sugar consumption and the risk of developing coronary heart disease.
Stare, joined by his Harvard colleagues D. Mark Hegsted and Robert McGandy, reviewed multiple medical studies, according to the JAMA report. An executive from the Sugar Research Foundation provided the medical studies that the foundation wanted to be reviewed, according to correspondence between the researchers and the foundation.
In the 1967 review published in the New England Journal of Medicine, the Harvard researchers found the evidence for connecting sucrose to coronary heart disease was "limited." They also concluded that sucrose consumption should not be considered in a patient's risk assessment for developing heart disease. Instead of drawing attention to sugar consumption, they concluded that more studies should be done examining cholesterol levels and the relationship with coronary heart disease. As a result in this review, the researchers influenced the focus of subsequent research by others to the risks of consuming saturated fats rather than the risk of consuming sugar, according to the JAMA report.
The Harvard researchers did not disclose they had been paid by the Sugar Research Foundation since the New England Journal of Medicine did not require researchers to disclose their funding until 1984.
Glantz said the 1967 review helped sidetrack any discussion of the link between heart disease and sugar consumption.
"In the review, there was double standard -- anything that was written against sugar was hyper-critical while research against fat had a free pass," Glantz told ABC News of the 1967 review.
Study co-author Dr. Cristin Kearn, a dentist and a post-doctoral fellow a the Philip R. Lee Institute for Health Policy Studies UCSF School of Medicine, said she initially looked into the subject after she asked about research on sugar and its impact on health at a dental conference. She said she hopes the new report will highlight the "implications for conflict of interest and industry-funded research."
"Current risk assessment studies, WHO, U.S. government agencies, should be sure to look at the scientific evidence and put less weight on industry funded research," she told ABC News.
The Sugar Research Foundation, which is now called the Sugar Association, admitted it should have been more transparent about its research funding in the 1960s, but noted the "last several decades of research have concluded that sugar does not have a unique role in heart disease"
"We acknowledge that the Sugar Research Foundation should have exercised greater transparency in all of its research activities, however, when the studies in question were published funding disclosures and transparency standards were not the norm they are today," the group said in a statement on Monday. "Beyond this, it is challenging for us to comment on events that allegedly occurred 60 years ago, and on documents we have never seen."
The American Heart Association now advises limiting added sugars in a diet to help avoid obesity, which can reduce heart health. The association cited a 2014 JAMA study that found a significantly increased risk of cardiovascular disease from high added sugar intake.
ABC News' Dr. Satyam Nayak contributed to this report. Nayak is soon to be an assistant professor and hospitalist physician at the University of Texas Southwestern Medical Center and is currently working in the ABC News Medical Unit.