An evening of drinking red wine can lead to a less than perfect white smile.
So it will come as a surprise to many that wine is apparently good for teeth and gums.
Chemicals in red wine can fight bad breath by fending off the bacteria which cause halitosis, a study has found. They may also prevent bleeding, swollen gums and irritation.
Sadly this does not mean swapping your mouthwash for a glass of merlot swilled round the mouth before bedtime.
The chemicals in the study by the Institute of Food Science Research in Madrid were used in far higher concentrations than occur naturally in wine, so would be less effective unless kept in the mouth for 24 hours.
The researchers found that the plant compounds which come from the grapes in the wine stopped bacteria sticking to human cells. It is when bacteria stick to gums and teeth, often in the form of plaque, that they cause gum disease and tooth decay.
Dr Victoria Moreno-Arribas, a co-author of the study, said: ‘We checked out the effect of two red wine polyphenols, as well as commercially available grape seed and red wine extracts, on bacteria that stick to teeth and gums and cause dental plaque, cavities and periodontal disease.
‘Working with cells that model gum tissue, we found that the two wine polyphenols – caffeic and p-coumaric acids – were generally better than the total wine extracts at cutting back on the bacteria’s ability to stick to the cells.’
There are more than 700 different types of bacteria in the mouth, two of which, called Porphyromonas gingavalis and Fusobacterium nucleatum, cause bad breath. The plant compounds in red wine managed to fend off both, along with a third, which cause swollen and irritated gums, tissue damage, bleeding and even detached gums.
In the case of F. gingavalis, the polyphenols in red wine cut the bacteria which stuck to the gum cells by up to 50 per cent.
The compounds studied are also found in coffee, grape juice and cranberry juice. Commenting on the research, Catherine Collins, from the British Dietetic Association, said: ‘This research is interesting if only because the researchers have used extracts of drinks we’re recommended to avoid if we want to keep our teeth white – and appear to have shown a possible benefit in reducing bacterial numbers and activity.’
But she added: ‘We might now sip red wine or coffee without guilt, but none of us hold drinks in our mouth for 24 hours at a time to reproduce this particular study method.’
Naveed Sattar, professor of metabolic medicine at the University of Glasgow, said: ‘People should not be fooled into thinking wine is good or health-giving, however much they would like to hear such a message.’