The sugar industry blocked the release of a study showing sucrose directly increases the risk of heart disease and cancer in 1968, newly-uncovered documents reveal.

The research, which was funded and designed by the sugar industry, was intended to dispel fears that fructose-containing sugars affect blood lipids. 

But internal correspondence uncovered by researchers at the University of California at San Francisco, show that industry leaders pulled the plug on its publication after getting wind that it would prove the clearest link between sugar and disease ever found. 

The finding, published today in PLOS Biology, is the latest in a series of bombshell reports from investigative researcher Dr Cristin Kearns and co-author Dr Stanton Glantz, who was the first researcher to reveal Big Tobacco was hiding research on the danger of cigarettes in 1996. 

Last year the duo sent shockwaves through the nutrition world with a study that showed the sugar industry had paid Harvard University's most respected nutrition scientist to play down the health dangers of sugar, and demonize fats. 

Speaking to Daily Mail Online, they say that, had this new study been published in 1968 as planned, it would have automatically triggered a review of sucrose by the US Food and Drug Administration, which would have likely led to regulation of sugar. 

Instead, they say, it has taken five decades for the scientific community to reach relative agreement that sugar is bad for you, and has a direct link to cancer and heart disease.

The researchers at the University of California at San Francisco say that, had this paper been published in 1968, it would have led to scrutiny and even regulation of sugar by the FDA

'The sugar industry has been playing the same games as Big Tobacco to protect their financial interests,' Dr Glantz told Daily Mail Online. 

'The more we look, the more we see that the sugar industry has had a sophisticated understanding of science for decades, sophisticated enough to manipulate it.

'This study, if it had been published, would have been quite cutting edge for its time. Had that work moved forward, it would've advanced the triglycerides-sugar debate forward by decades.

'That's why they killed it.'

Today's paper - the third collaboration between Glantz and Cearns, and the fourth on this subject for Cearns, a dentist-turned-investigator - is based on a review of archived industry documents.

It reveals the Sugar Research Foundation (SRF), now known as the Sugar Association, funded an animal experiment called Project 259 to evaluate sucrose's effects on cardiovascular health.

But, as with many research papers, it got delayed. The researcher, excited by his findings, went to the SRF asking for another boost in funding to take his work further. 

Reviewing the data, which indicated an association with heart disease and bladder cancer, the SRF pulled the plug on the entire project.   

Dr Cearns explains that this study would have triggered scrutiny or regulation of sucrose.

At the time, the FDA was operating under something called the Delaney clause, which made is compulsory to scrutinize or regulate anything that was found to have a cancerous link based on an animal study. 

In fact, a year before, the SRF had criticized animal studies. For unknown reasons, the foundation went on to fund its own animal study - but shut it down when they heard the damning findings. 

Even today, the Sugar Association denies that sugar has any direct detrimental health impacts beyond weight gain.  

Last year the Sugar Association criticized a mouse study suggesting a link between sugar and the growth and spread of tumors.

They said 'no credible link between ingested sugars and cancer has been established.'

The analysis of the industry's own documents, in contrast, suggests the industry knew of animal research indicating this link, and halted funding to protect its commercial interests half a century ago.

Dr Kearns said she knows of at least 300 industry-funded studies between 1943 and 1972. 

'There is more material than I have the ability to write about,' she told Daily Mail Online. 

'We will need far more investigators to uncover all of this.'

Dr Glantz concurs. 

He was the first to concretely highlight tobacco's direct links to disease, after receiving more than 4,000 pages of internal Big Tobacco documents in 1994 from an anonymous source. The documents unveiled decades of manipulated research and hidden data proving that cigarettes cause disease.

Dr Glantz went on to publish a book called The Cigarette Papers, which paved the way to more than 1,000 research papers on cigarettes and disease. 

Now, he says, we are seeing the same with sugar.

'The kind of manipulation of research is similar what the tobacco industry does,' he claims. 

'This kind of behavior calls into question sugar industry funded studies as a reliable source of information for public policy making.'

His previous analysis with Dr Kearns found the SRF had secretly funded a 1967 review playing down evidence linking sucrose consumption to coronary heart disease.

That noted gut microbes may explain why rats fed sugar had higher levels of cholesterol than those fed starch, but dismissed the relevance of animal studies to understanding human disease.

The foundation launched its coronary heart disease research in 1965. The first project was the review published in the New England Journal of Medicine in 1967.

It focused on fat and cholesterol as the dietary cause of coronary heart disease, while downplaying sugar consumption as a risk factor.