URBAN health myths abound - a titanium necklace can prevent neck pain and a cactus next to your computer can protect you from radiation. Zhang Qian talks to a health rumor terminator and other expert debunkers.

Rumors about health dangers and tips are always swirling about or simmering, fanned by the Internet and repetition by people who don't consider the facts.

Remember the panic buying of iodized salt in March during the crisis at the Japan's Fukushima nuclear reactor? People mistakenly thought iodized salt would protect them from radiation, since iodine tablets can help ward off the effects of some kinds of radiation.

Some rumors have acquired the status of cherished urban legends or myths, like putting a cactus next to a computer screen to absorb radiation, playing Mozart to a fetus in utero to make the child smarter and wearing a titanium necklace to ease fatigue and relieve neck pain.

Believers make credible-sounding arguments, and many people say "better be safe than sorry." Merchandisers cash in. Some rumors are strengthened by the well-known placebo effect and the power of suggestion - in other words, if you think it will make you feel better, you will feel better.

All these claims, and many more, are rubbish.

One man in Shanghai, an anesthesiologist, is dedicated to debunking health myths and has recently published a book titled "Health Rumor Terminator."

"I often hear rumors about health from friends, and as a medical worker I am always interested in finding out whether there is any scientific basis for them," says Bo Sanlang (his Internet name), who practices at the No. 2 Military Medical University. He does his research, consults experts and often finds that rumors and conventional wisdom are wrong.

Bo is also an active health myth buster for Rumor Disintegrator/smasher (Yao Yan Fen Sui Ji) on Guoke.net, a platform that tries to dispel health rumors with easy-to-understand scientific explanations. Bo is one of the writers for the website.

He tells Shanghai Daily that he has asked many friends, including doctors and highly educated people, about various rumors - for example, about increasing infant IQ by playing music to the fetus and wearing titanium to ease neck pain.

"Most people will say they believe the sayings - they say that since so many people are talking about it, there must be something to it, there must be some science in it," says Bo.

But no matter how many times a falsehood is repeated, it doesn't become the truth.

Classical music, including Mozart, may be soothing for a pregnant mother and fetus, but it has never been proved to increase intelligence, says Bo, adding that there's abundant research debunking available, but rumors persist about making a baby smart in the womb.

"Our enemy here is not the rumors, but the way that we blindly take what other people say without a second thought," says Ji Shisan, CEO of Guoke.net.

Cactus for radiation

It's common to see a cactus placed on an office desk next to a computer screen. Many professionals believe that cactus spines absorb radiation released by computers. The idea seemed to emerge from nowhere long ago, when people became aware of radiation and concerned about spending long hours in front of a computer.

It's an urban legend. The cactus doesn't help and the computer's non-ionizing radiation is essentially harmless.

In fact, everyone is exposed to radiation all the time, from the sun and cosmic rays, electrical and electronic appliances, earth and rocks. Computer radiation is non-ionizing - it doesn't release damaging free radicals, as do X-rays and nuclear leaks. A plant has no impact on radiation.

"I read that cactus can absorb and resolve the radioactive toxins around since it contains a lot of water; in that case, wouldn't a bowl of water be better?" says Bo.

The source of the legend may be the fact that cactus survives in deserts with intense solar radiation, but that doesn't mean it can dispel radiation, say experts.

Every living thing, animal and plant, can absorb a little radiation, according to Wu Zhixing, senior engineer of Shanghai Landscape Architecture society.

"But cactus is not a kitchen ventilator, all it can do is block some radiation that travels through it," says Bo, "and then it would have to be between the computer and the user."

Titanium for fatigue

Wearing a titanium necklace was trendy for a while, and many people still believe that wearing one can prevent and treat fatigue and soreness in the neck caused by bad posture and spending a lot of time in front of a computer.

It is said that the necklaces, which are widely advertised, can adjust micro currents of the body, release infrared rays and thus relieve sore muscles, promote metabolism and ease stress.

There's no special "micro current" of the human body, says Bo, though there is bioelectricity at a cellular level. "There's no medical evidence that titanium can influence any energy in the body, raise the temperature, let alone accelerate blood circulation and relieve pain."

Though some people swear they feel better when wearing a necklace, the reason is the great power of psychological suggestion, says Bo. People always hear about the wonders of science and technology, they want to feel better and so they do, he says. It's not magic, it's mental.

Professor Wang Jian, a specialist in sports medicine at Zhejiang University, says tests show a titanium necklace has no effect whatsoever on muscle strain or fatigue.

"A titanium necklace is more like a decoration with a psychological consoling function," says Dr Qiu Dehua of orthopedics and traumatology at Huangpu District Central Hospital.

"If a titanium necklace could really treat disease, it would be sold only in hospitals and pharmacies as a medical apparatus, not in ordinary shops," he says.

Vitamin B1 for mosquitoes

Lately it is said that dissolving some vitamin B1 pills in a small bottle of water and spraying it on the body can repel mosquitoes.

The smell and bitter taste is probably why people think it may repel the insects, but it cannot, according to Bo. Mosquitoes are attracted by certain body chemicals and heat, but Vitamin B1 has no effect.

Genetics determines whether mosquitoes find someone appealing.

The legend about the vitamin has a long history, probably dating back to an article published in an American medical magazine in the 1940s. No research has confirmed it. Too much vitamin B1 an interfere with absorption of other B vitamins.