A review of the science behind the celebrity fads of the past 12 months has revealed that this could be the year when some famous names have turned their backs on the unsubstantiated claims of the alternative treatments industry, according to campaign group Sense About Science.
But despite signs of intelligent life in celebrity cuckoo land, there were still many examples of the sublimely ridiculous, from rubbing coffee granules into your skin to using coloured sellotape to 'mend' injuries.
"We seem to be seeing a celebrity divide on science. The implausible and frankly dangerous claims about how to avoid cancer, improve skin or lose weight are becoming ever more ridiculous," said Tracey Brown, of Sense About Science.
"On the other hand, this year we have had more examples than ever of people in the public eye who clearly do check their facts."
The Mad Men actress admitted to eating her own placenta after the birth of her baby son. Catherine Collins, principal dietician at St George's Hospital, London, said: "Nutritionally, there's little to be gained from eating your placenta ... [in fact] your placenta will provide toxins and other unsavoury substances it had successfully prevented from reaching your baby."
The EastEnders actress was reported to rub coffee granules into her skin as a cellulite treatment. Gary Moss, a pharmaceuticals scientist, said: "There's a perception that coffee might tackle cellulite because caffeine can penetrate the skin. However, as coffee granules won't allow the caffeine to penetrate the skin barrier, the only unintended effect is perhaps exfoliation."
The Manchester City footballer is one of several sporting superstars who was seen in 2012 wearing Kinesio coloured sports tape that purports to "mend" injuries. Professor Greg Whyte, sports scientist, said: "It's unclear how [the tape] can positively affect inflammation deep within the muscle."
The TV and music producer said he carried small, inhalable bottles of oxygen around with him to reduce the effects of tiredness, stress and signs of ageing. Kay Mitchell, researcher into extreme environments, said: "Breathing 100pc oxygen under pressure allows oxygen to dissolve into the blood plasma. ... While this is thought to improve recovery rates from sports injuries...more research is needed."
The singer said that she spent hours on her old mobile phone and questioned whether this may have been the cause of her brain tumour. Mireille Toledano, epidemiologist and expert on mobile phone risks, said: "Overall, the evidence to date is clear that short-term use of mobile phones is not linked to brain cancers."
The actress said that teaching children about the function of the brain helped them to understand where their emotions come from. Professor Sergo Della Sala, neuroscientist, said such teaching would not work, any more "than understanding the chemical components of a ball would help them to kick it".
The actress said she had stopped dieting and just ate moderately because "fads are too much". She also said fasting and "cleansing" were bad for the body. Ursula Arens, of the British Dietetic Association, said: "Extreme diets and fasts will make you feel unwell and do not support good health. A fantastically sensible comment, Jennifer."
The comedian said that popping vitamin pills is a waste of time. Lucy Jones, of the British Dietetic Association, said: "Al, you are right ... supplements are like glasses: not everyone needs them and you need to get the right prescription."