History is littered with quack doctors, charlatans or marketing executives who all promise to fulfil our desires with a certain product, diet, belief or cure.

Most modern consumers are savvy enough to see through their rhetoric. But when celebrities advocate the best way to look great, feel young or stay slim and successful (just like them) – or worry about the latest threat to health – we are tempted to listen.

That does not mean, however, that they know what they are talking about, as Sense About Science shows today.

Role models previously highlighted by the charity for talking nonsense have included Gwyneth Paltrow, who said: “I am convinced that by eating biological foods it is possible to avoid tumours”, and Stella McCartney, who came under fire for comments about the dangers of skin care products containing the same petrochemicals as antifreeze. Few would expect Tom Cruise’s view of psychiatry – that it is a “Nazi science” – to be impartial while he is a practising Scientologist. Some celebrities may be genuinely well meaning when offering their views; others are simply out of their element, or have products to plug.

Misleading claims can travel widely, when broadcasters, the media or a celebrity’s fanbase hangs on their every word, especially the most wacky or controversial.

Satirists have also demonstrated how willing some celebrities are to parrot any old rubbish in the pursuit of publicity or votes, as when Chris Morris, the creator of Brass Eye, once persuaded MPs and broadcasters to demonise a fictitious drug, “cake”.

They should have known better. As should Barack Obama, who told voters this year that he suspects that vaccines have caused an increase in autism among children. For some parents of autistic and other children, the MMR jab has continued to provide a convenient explanation for why their children may not have developed healthily.

But an overwhelming tide of robust, peer-reviewed evidence, involving millions of children in different countries, suggests that they are wrong. In dismissing this science as “inconclusive”, Mr Obama (perhaps unwittingly) has done himself a disservice, as do other public figures who do not check their facts before speaking.

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