Sugar companies paid Harvard scientists to release their 1960s study to downplay the link of sugar as a risk factor for coronary heart disease. They placed the blame on fat intake instead, a newly released historical document shows.

In a new study by scientists from the Institute for Health Policy Studies and the University of California, San Francisco, the internal sugar industry documents suggest that the results of five decades of studies have been greatly shaped by the sugar industry.

Published in the journal JAMA Internal Medicine, the analysis is based on the correspondence between the scientists at Harvard University and a sugar trade industry, Sugar Association, which evolved from the Sugar Research Foundation (SRF). In 1964, the group secretly discussed a campaign to downplay the link of sugar to coronary heart disease (CHD). It aims to stem the negative attitudes toward sugar when various studies emerged and released a possible link between sugar and heart disease.

"The literature review helped shape not only public opinion on what causes heart problems but also the scientific community's view of how to evaluate dietary risk factors for heart disease," said study investigator Cristin Kearns from the University of California San Francisco, who discovered the industry documents.

The researchers examined more than 340 documents between two individuals and the sugar industry. The two scientists are Roger Adams, a professor of organic chemistry who is part of the scientific advisory boards for the sugar industry and Dr. Mark Hegsted, one of the Harvard scientists who released the study back in the '60s.

The first link between sugar and heart disease was released during the 1950s. After more than a decade, the SRF funded a literature review in 1965, focusing more on the role of fat and cholesterol in the development of CHD.

The researchers of the newly released historical document call for unbiased scientific studies by people who do not have conflicts of interests.

"As the saying goes, he who pays the piper calls the tune," said co-author Stanton A. Glantz, a professor of medicine at UCSF.

"There are all kinds of ways that you can subtly manipulate the outcome of a study, which industry is very well practiced at," he added.