Fake news has been in the real news recently because of what we have learnt of the media consumption habits of many Donald Trump supporters. As we report today, however, it is not just in the field of politics that fake news is a problem. Our investigation has found that untrue or misleading news stories about health are often shared more widely online than evidence-based reports from reputable news organisations.

Of the 20 most-shared articles on Facebook in 2016 with the word “cancer� in the headline, more than half report claims discredited by doctors and health authorities.

David Colquhoun, professor of pharmacology at University College London, who runs a blog dedicated to exposing quackery, explains that it is most often found “in areas where conventional medicine can’t do as much as people would wish�. Part of the problem is the success of modern medicine, which has “led people to think there’s a cure for anything, which there isn’t�, and fake medicine has moved in to fill the gaps.

It is hard to know how much of this is new or worse than it used to be. After all, quack remedies have been offered and eagerly taken up for all the history of medicine.

It may be that many of those who share fake health news are people who already believe anti-science superstition, just as many of those who shared fake political news about the US presidential election were already committed Donald Trump voters. Indeed, there appears to be an overlap between the two groups: Trump supporters who buy into conspiracy theories are also more likely to be anti-vaccine and as suspicious of authority in medicine as they are of the “Washington elite� in politics. Meanwhile on this side of the Atlantic we are in an age when a leading politician can say that Britons “have had enough of experts�, and find a large audience eager to agree with him.

The Independent tends to take the optimistic view that, although the internet allows the faster spread of untruths to more people than ever, it also allows faster rebuttal of untruths and greater reach for useful public health messages. That does not mean, of course, that it can be assumed that the internet is a self-regulating universe of free speech in which good science will automatically drive out bad. Politicians and healthcare professionals have a responsibility to try to help people to make sense of complex and disputed information that is available.

At least we have moved beyond the days when GPs would express irritation if a patient had looked up his or her symptoms online. Doctors and health authorities now understand the importance of using the internet to give people clear and trusted health information.

That responsibility needs to be shouldered too by the big companies that make money out of the internet. Mark Zuckerberg, the founder of Facebook, has made a late start. The company has introduced a system to allow users to flag disputed news shared on the site. This is a simple device but a hugely important first step. It means that any reader not already rigidly committed to conspiracy theories might stop to check the information with a trusted source. Google also needs to come up with clever ideas for the way its search engine deals with fake news.

And of course there is a wider civic responsibility, much of which will be borne by our schools, in educating people not just in the basics of the scientific method – has a “cure� been tested in a randomised control trial, and how would we know? – but in how to use the internet sceptically and intelligently.