Brush teeth to 'prevent' heart disease

People who fail to brush their teeth twice a day are putting themselves at risk of heart disease, research suggests.

The Scottish study of more than 11,000 adults backs previous research linking gum disease with heart problems.

The researchers said more work is needed to confirm if poor oral health directly causes heart disease or is a marker of risk.

A charity added that oral hygiene was just one factor in good heart health.

It is known that inflammation in the body, including in the mouth and gums, has an important role in the build up of clogged arteries, which can lead to a heart attack.

But this is the first time that researchers have looked at whether the frequency of teeth brushing has any bearing on the risk of developing heart disease.

Then nurses collected information on medical history and family history of heart disease, took blood pressure and blood samples.

Overall, six out of 10 people said they visited the dentist every six months and seven out 10 reported brushing their teeth twice a day.

Over the eight-year study there were 555 "cardiovascular events" such as heart attacks, 170 of which were fatal.

Cause and effect

Study leader Professor Richard Watt, from University College London, said future studies will be needed to confirm whether the link between oral health behaviour and cardiovascular disease "is in fact causal or merely a risk marker".

Judy O'Sullivan, senior cardiac nurse at British Heart Foundation, said: "If you don't brush your teeth, your mouth can become infected with bacteria which can cause inflammation.

"However, it is complicated by the fact that poor oral hygiene is often associated with other well known risk factors for heart disease, such as smoking and poor diet."

She added: "Good personal hygiene is a basic element of a healthy lifestyle.

"But if you want to help your heart, you should eat a balanced diet, avoid smoking and take part in regular physical activity."

Professor Damien Walmsley, scientific adviser to the British Dental Association, added it was still unclear whether there was a definite cause and effect between oral hygiene and heart disease.

"Whatever the true position is, we can say with certainty that if people brush teeth twice a day with fluoride toothpaste, visit the dentist regularly and restrict sugary snacks to mealtimes; that this will go a long way towards keeping the teeth and gums in a healthy state for life."

Bee stripes may not keep predators away

Bumblebees' distinctive bright yellow and black stripes may not be what keeps them safe from their enemies, scientists say.

A UK study has shown that other aspects of bees' behaviour may matter more than the classic bee colour to keep predators away.

This could be the way bumblebees fly or perhaps the buzzing sound they make, say the scientists.

The results of the study were published in the Journal of Zoology.

Scientists have long believed that once flying predators get stung by a bee, they remember their experience and in the future rely strongly on colour cues to identify their prey.

"The first time a bird eats a brightly coloured bumblebee it gets a nasty surprise. Remembering the bee's bright colours may help the bird to avoid making the same mistake again," said Dr Nigel Raine from the School of Biological Sciences at Royal Holloway, University of London, a researcher on the study.

Birds perceive the world differently to humans, being able to see light in the ultraviolet range of the spectrum. But they can still distinguish between different species of bees, explained the scientist.

So the researchers wanted to check if bees' colours were the only thing that helped to warn off predators.

'Unexpected' results Dr Raine and his colleagues from the University of London set up a number of colonies from different populations of bumblebees in the UK, Germany and Sardinia.

Though some insects had similar colour patterns - bands of bright yellow, white, orange or red and regions of black, others looked quite different from one another.

"In the UK, they are yellow-and-black-striped with a white tip on the abdomen, but in the Canary Islands for example they don't have any yellow bands at all - they're just black and white," said Dr Raine.

The scientists expected birds to rely on visual clues, meaning they would be more likely to attack bees that looked different from the ones they were used to.

"All our bees were individually numbered with tags on the back of the thorax, so that we could keep track of each individual that left and entered the nest," said the researcher.

The scientists then counted how many bees did not return to their nest and compared the loss rate of different Bombus terrestris populations with different colour patterns in the same environment.

They got some rather unexpected results, said Dr Raine.

"Predators didn't seem to target the unusually coloured bees more than the native populations we tested. Perhaps the bumbling way in which all bumblebees fly or their distinctive deep buzzing are more important clues to help would-be predators avoid a nasty sting," he said.

His colleague Ralph Stelzer, the main author of the study and a PhD student at Queen Mary, University of London, called the findings surprising.

"The results mean that the explanation for the bumblebees' colouration patterns is not as simple as previously thought,"