The old wives' tales that are true

LONG, HOT BATHS REDUCE SPERM COUNT

It's long been supposed that long, hot baths were not a good idea for men who wanted to father children. Now, researchers at the University of San Francisco have found this to be true. When men accustomed to lingering in the bath for an hour or more were told to take showers instead, the sperm counts of half rose by nearly 500 per cent. The other half were smokers and it was thought this is why theirs didn't respond. Sperm need cool temperatures in order to develop - that's why the testicles are outside the body.

SEIZURES ARE BROUGHT ON BY A FULL MOON

When researchers at the University of Patras Medical School in Greece probed the old tale that seizures are more likely to occur under a full moon, they found that there could be something to it. They reviewed all records of 859 patients admitted for seizure and found "significant clustering of seizures" around the full moon.

CARROTS HELP YOU TO SEE IN THE DARK

Just how this old wives' tale got going is not known, although legend has it that British military intelligence during the Second World War spread the word that plane-spotters were eating carrots to cover up the fact that it was radar which was responsible for the increase in downed German planes. But researchers at the Erasmus Medical Centre in Rotterdam have found that ingesting high levels of beta carotene - the compound that gives carrots their colouring - as well as vitamins C, E and zinc lowers the chance of age-related macular degeneration by up to 35 per cent. Other sources of beta carotene include pumpkins, sweet potatoes, pink grapefruit and spinach.

FEED A COLD, STARVE A FEVER

While a lot of research says this is not true, a small Dutch study at the Academic Medical Centre, Amsterdam, suggests there may be something in it. Volunteers fasted overnight and then were given either water or a meal the next day. Those that drank the water showed raised levels of a compound that fights infections linked to fevers, while those who had the meal experienced higher amounts of a compound that tackles viral infections like colds.

I CAN FEEL IT IN MY BONES

Many people with arthritis claim that their joint pain varies with weather conditions. The idea is often rejected, but a study based on 130 patients with osteoarthritis or rheumatoid arthritis at the Instituto Poal de Reumatologia in Barcelona found that arthritic patients had increased joint pain when there was a drop in atmospheric pressure. They also found that low temperatures increased joint pain in patients with rheumatoid arthritis. "Our data demonstrate that osteoarthritic patients experience increased joint pain in response to a decrease in pressure,"say the researchers.

LONG LABOUR, MUST BE A BOY

Ultrasound scans may have taken the mystery out of knowing whether it's a boy or a girl, but for those who still rely on old technology, this tale may have some truth in it. Research at Dublin's National Maternity Hospital, based on 8,000 births and reported in the British Medical Journal, showed that male births were significantly more likely to result in longer labour. "When we say 'it must be a boy', as a humorous explanation of complications of labour and delivery, we are scientifically more correct than previously supposed," say the researchers.

HEARTBURN IN PREGNANCY MEANS A HAIRY BABY

It may sound unlikely, but researchers at Johns Hopkins University found some truth in this. They examined 64 pregnant women, ranked the severity of any heartburn, and compared it with newborn hair coverage using photographs of the infant's head taken shortly after birth. Most (23 out of 28) women who reported moderate or severe heartburn gave birth to babies with average or above average amounts of hair, while most (10 out of 12) women reporting no heartburn had babies with less than average or no hair. "Contrary to expectations, it appears that an association between heartburn severity during pregnancy and newborn hair does exist," say the US researchers. Exactly how it works is not clear, but the theory is that one doesn't cause the other, rather that they share a common cause, which is probably hormonal. "The findings suggests that sometimes old wives may be right," they add.

GAIN A CHILD, LOSE A TOOTH

Research at New York University College of Dentistry shows a link between the number of pregnancies and dental problems. The team looked at 2,635 women aged 18 to 64 who reported at least one pregnancy, and found that many also experienced problems with their teeth. Dr Stefanie Russell, who led the research, says that pregnancy raises the risk of gingivitis, and if a woman has repeated outbreaks of gingivitis, she may develop periodontal disease. Mothers with several children may also be more likely to eat the junk food their children are eating.

WRAP UP AND AVOID A COLD

One of the most widespread old wives' tales is that if you get cold, you will catch a cold. Science was unable to demonstrate any effect of cold exposure on susceptibility to infection, until a study at Cardiff University showed that the chilling of the feet can lead to increased risk of a cold. In the study, 80 people had their feet chilled and a similar number did not. Results showed that 13 out of 90 who were chilled suffered from a cold the following week, compared to only five of the others.

FISH IS FOOD FOR THE BRAIN

Just who first had the idea, many years ago, that fish was a brain food is not known, but whoever it was probably didn't know too much about docosahexaenoic (DHA). A number of researchers have now found that fish oil may play a part in the development and functioning of the brain. Fatty fish like mackerel, herring, sardines, tuna and salmon are rich in two kinds of omega-3 fatty acids, eicosapentaenoic acid (EPA), and DHA. A study at Rush University, Chicago, shows that among people over 65, fish intake was associated with a slower rate of cognitive decline. Compared to people who ate fish rarely, those who had fish once a week had a 10 per cent slower rate of decline.

AN APPLE A DAY KEEPS THE DOCTOR AWAY

An apple or three a day may not only keep the doctor away, but it might lower the risk of breast and colon cancer. Research at the University of Ulster suggests that high levels of apple phenols, which work as potent antioxidants, may have a beneficial effect on colon cancer cells. "Our results indicate that a crude extract of apple phenolics can protect against DNA damage," they say. Researchers at Cornell University, in the US, found that, in animals, apples prevented mammary cancers. The doses given, were, they say, comparable to human consumption of one, three, and six apples a day. "Consumption of apples may be an effective strategy for cancer protection," they add.

But they were wrong about these...

The full moon and mental health

It's a popularly held belief that psychiatric behaviour worsens during a full moon, but a study at the naval medical centre in San Diego, based on more than 8,000 admissions, showed that were no more on days with a full moon, or indeed with a new moon. "Lunar phase was not associated in any significant way with psychiatric admissions or emergency presentation," the study concluded.

Early to bed and early to rise makes a man healthy, wealthy, and wise

A study at Southampton University based on 1,200 men and women over 23 years showed that there was no evidence that early risers were richer, or healthier, or wiser than later risers. In fact, night birds had larger incomes.

Avoid surgery under a full moon

Study based on 3,757 breast-cancer-surgery cases at Lainz medical centre, Vienna, which was carried out to find out whether the timing of surgery during particular lunar phases influenced the survival of breast cancer patients, found that it didn't. "No significant differences in overall survival of breast cancer patients were observed. Results do not support any recommendations for scheduling patients for surgery at any particular day of the lunar phase," it decided.

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