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Harvard hospital admits it promoted weak science on aspartame

A new study finding a potential cancer risk from the artificial sweetener aspartame is so weak that Brigham and Women’s Hospital  -- a Harvard teaching facility -- is now apologizing for promoting the research. In other words, if you see a headline screaming, “Aspartame linked to cancer,” don’t believe it. But it may be too late; the situation is a great example of why the public often finds science confusing and frustrating.

Earlier in the week the hospital sent out a press release about the study with the headline “The truth isn’t sweet when it comes to artificial sweeteners.”

After being asked some hard questions – and just before the report was to be released --  the hospital changed its tune, issuing a statement that said: “Upon review of the findings, the consensus of our scientific leaders is that the data is weak, and that BWH Media Relations was premature in the promotion of this work. We apologize for the time you have invested in this story.”

Aspartame is one of the most studied food additives ever -- and with good reason.  It is an ingredient in some 6,000 products, but its main use is to sweeten diet sodas. Americans drink an astounding amount of diet soda, the equivalent of 43 billion 12-ounce cans a year.

Most animal and human studies have given aspartame a clean bill of health. But in 2005 an Italian study showed a potential danger in rats that led epidemiologist Dr. Eva Schernhammer and her team at Brigham and Women’s Hospital to look through the records of more than 77,000 women and 47,000 men in their nurses and health professional’s studies. They concluded that those who drink a daily diet soda sweetened with aspartame could have an increased risk of leukemia, lymphoma or non-Hodgkin's lymphoma.

But there are caveats: The results differed between women and men, and there also seemed to be a risk among people who drank mostly sugared soda.  No one claimed that it meant more than further study was need.

Yet when lead author Schernhammer was asked whether the new research proves that aspartame is dangerous, she answered emphatically, “No, it does not.”

Not all science deserves publicity. Some is not done well. Some comes to equivocal conclusions and serves solely to alert other researchers of the need for further study. The research out Wednesday about a potential cancer from aspartame falls squarely in that second category. If such a study does get attention, it can often increase the confusion and anger that many people feel about science in general – and the study of possible risks and benefits of our diet, in particular.

The conclusion was so weak that the researchers had to submit it to six journals before they found a seventh, the American Journal of Clinical Nutrition, that would publish it. Few reporters read that journal. If it was not for the frightening headline no one would have known about this study.

As Dr. Steven Nissen, chair of the Cleveland Clinic’s cardiovascular medicine department put it to me: “Promoting a study that its own authors agree is not definite, not conclusive and not useful for the public is not in the best interests of public health."

Now, the media department at Brigham and Women’s have come to believe they did exactly that.

Robert Bazell is NBC's chief science and medical correspondent. Follow him on Facebook and Twitter.

Correction: An earlier version of this report contained an incomplete name of the journal that published the research.

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