Odd science claims made by various celebrities - about diets, cancer, reabsorbing sperm, hologram bracelets and more - make no scientific sense, according to a campaign group.

The UK-based Sense About Science (SAS) group asks scientists to respond, to help the celebrities realise where they are going wrong and to help the public to make sense of celebrity claims.

This year, we have seen the biggest rise in dubious theories about how the body works, SAS says.

A diet used by Naomi Campbell, Ashton Kutcher and Demi Moore this year is the ‘Master Cleanse’, where followers survive on maple syrup, lemon and pepper for up to two weeks with nothing else to eat. In an interview with Oprah Winfrey, Naomi Campbell explained: “it’s good just to clean out your body once in a while.

However, Ursula Arens, a dietician at the British Dietetic Association (BDA), said: The body has many natural functions that eliminate substances which would be 'toxic' if allowed to accumulate. Most diets have no effect on the rate of these physiological functions and do not improve the quality of ‘cleansing’ in the body.

David Beckham and Kate Middleton have been spotted wearing a hologram-embedded silicone bracelet called Power Balance, which claims to improve energy and fitness. Celebrities sporting the bracelets have included David Beckham, Robert de Niro, Kate Middleton and even Spanish Ministers of State.

Any perceived performance enhancement from wearing the Power Balance bracelet is likely to be a placebo effect, says Professor Greg Whyte, sports scientist, Liverpool John Moores University.

Cheryl Cole reputedly extolled a weight loss regime based on her blood group.Cole tried the blood type diet, which claims that people with different blood groups break down food in different ways and should eat different things.

However, Sian Porter, dietitian at the BDA said: Your blood group cannot affect digestion or the way food is broken down - this theory is really just another spin on reducing overall calorie intake.

Cage fighter Alex Reid gave fans his tips on how to prepare for a match as he promoted his new fight show, Alex Reid: The Fight of His Life. He said: “it’s actually very good for a man to have unprotected sex as long as he doesn’t ejaculate. Because I believe that all that semen has a lot of nutrition. A tablespoon of semen has your equivalent of steak eggs, lemons and oranges. I am reabsorbing it into my body and it makes me go raaaaahh.”

But, John Aplin, a reproductive research scientist at the University of Manchester, said sperm can't be -reabsorbed once they have formed in the testes. In fact sperm die after a few days, and the nutritional content of the ejaculate is really rather small.

Many of these claims promote theories, therapies and campaigns that make no scientific sense, SAS said.
Lindsay Hogg, Assistant Director, SAS said: We’d like to see more celebrities checking out the science before they open their mouths and send the wrong thing viral.

To improve the outlook for 2011, SAS has published scientists’ responses into easy-to-remember points for celebrity commentators.

* Nothing is chemical free: everything is made of chemicals, it’s just a case of which ones.
* Detox is a marketing myth: our body does it without pricey potions and detox diets.
* There’s no need to boost: bodily functions occur without ‘boosting’.
* Energy and fitness come from...food and exercise: there are no shortcuts.