People who brush their teeth more often stay slimmer, according to a recent Japanese study. In a survey of the everyday habits of nearly 14,000 people whose average age was in their mid-40s, Dr Takashi Wada of Jikei University in Tokyo found that those who managed to stay slim tended to brush their teeth after every meal.

The study, published in the Journal of the Japan Society for the Study of Obesity found that overweight men sometimes went more than a day without brushing their teeth.

Dr Wada and his team compared the lifestyles of people whose body mass index (BMI) was over 25 – the level doctors define as overweight – with those of slimmer people. The survey covered eating and drinking habits, sleep, work and exercise.

The results do not mean that brushing in itself constitutes a fat-burning exercise, the authors say. “It's a sign that these people are careful about their health – they want to maintain the appearance of their teeth and prevent bad breath,” the paper said. “We think actively encouraging the habit of toothbrushing would play a role in maintaining health and would help prevent obesity.”

Meanwhile a separate study has reported that brushing your teeth could reduce the risk of having a stroke or heart attack.

A team from Columbia University found people with gum disease were more likely to suffer from atherosclerosis - a narrowing of blood vessels, a condition can precede a stroke or heart attack.

Published in the journal Circulation, researchers looked at levels of bacteria in the mouths of 657 people who had no history of stroke or myocardial infarction (heart attack). The researchers also measured the thickness of the subjects' carotid artery, which carries blood from the heart to the brain, and which is measured to identify atherosclerosis.

It was found that those people who had a higher level of the specific bacteria that causes periodontal disease also had an increased carotid artery thickness, even after taking other cardiovascular risk factors into account.

The team also found that the link with atherosclerosis only existed for the bacteria which was known to cause gum disease, and not other bacteria found in the mouth.

The British Heart Foundation welcomed the study but said it would encourage people to follow a healthy lifestyle to reduce their risk of heart disease.