Who do you turn to for news and information about science and health issues? Television? Newspapers? Industry groups? The Internet?  Recent polls have found that public trust in many of these sources is very low.  The most trusted sources of science and health information tend to be experts and medical professionals, as well as non-government organizations.  At the bottom end of the trust spectrum are industry groups.

The public has good reason to be skeptical. Health and science issues are particularly open to manipulation, since they are often complicated and hard for the layperson to grasp in short articles or stories. And it seems that some groups will go to any lengths to distort scientific information.

For example, a 247-page report recently released by the World Health Organization (WHO), details how tobacco companies have systematically sought to undermine WHO's research and efforts to curb tobacco use for more than a decade.  Tactics used by the tobacco companies included paying WHO employees to spread misinformation, hiring institutions and individuals to discredit the WHO, secretly funding reports designed to distort scientific studies and even covertly monitoring WHO meetings and conferences. Confidential tobacco company documents do not mince words as to the industry's goals, using phrases like: "Discredit key individuals," "Attack WHO," and "Work with journalists to question WHO priorities, budget, role in social engineering etc."

The report also notes that, "Tobacco companies have conducted an ongoing, global campaign to convince developing and tobacco-producing counties to resist WHO tobacco control policies."  These tactics appear to have been successful, as is evident from the growth in cigarette sales in developing nations such as China. There are now more than 300 million smokers in China consuming 1,700 billion cigarettes every year - a figure that has tripled since 1978. In the coming decades, smoking is expected to surpass infectious disease as the leading threat to human health world-wide.

Profit is the obvious motive for the tobacco industry's manipulations, but the media are not immune to distortions and fabrications of their own. For example, in a segment on organic food appearing on ABC's vaunted 20/20 news program this spring and again this summer, a reporter actually fabricated some scientific test results and distorted others to make his story more sensational and fit the desired angle.

In the segment, the reporter said that tests by ABC found no pesticide residue on conventional produce, so buying organic produce to reduce exposure to pesticides was essentially a waste of time. After the segment aired, the US-based Environmental Working Group questioned the claim and found that no such tests were ever actually conducted. In fact, tests by the US Environmental Protection Agency have found residue from at least 12 different pesticides on 90 per cent of conventionally grown celery, 53 per cent of lettuce and 26 per cent of broccoli.

 The ABC reporter also misrepresented tests for e-coli bacteria to make organic produce actually seem dangerous. At one point, he held up a bag of organic lettuce and confronted the head of the organic industry's trade association, proclaiming: "Shouldn't we do a warning that says this stuff could kill you and buying organic could kill you?" With no evidence to back up these claims, the reporter has since apologized and been reprimanded by the network.

Even peer-reviewed scientific journals can sometimes suffer from distorted, or even fraudulent scientific claims. In a recent editorial in the prestigious journal Science, for instance, it is reported that the journal had unknowingly published a study based on manipulated data, thus invalidating not only that study but another that had been based on the original article. Such cases are rare, but they can happen.

There is no way to be 100 per cent certain of the veracity of any science news, but we can use our best judgments to achieve reasonable certainty. We have to weigh the balance of evidence, consider the credentials and motives of the source and think critically. It's not always easy, but that's the price of being truly informed.