White wine 'erodes teeth'

“White wine rots your teeth... and brushing makes it worse,” claimed the Daily Mail today. The newspaper said that white wine is more damaging to your teeth than red wine, as it wears the tooth enamel away more quickly. 

The research behind this story soaked a number of extracted teeth in different wines for up to 24 hours, which found that white wines caused more tooth erosion and calcium loss than red wine. Although this scientific study was well-conducted, it does not represent real life as teeth would never be soaked in wine for up to 24 hours, and wine would not normally be held in the mouth for extended periods of time.

As the study was carried out on extracted teeth in the laboratory, it is also not possible to fully appreciate the effects that saliva, diet and nutritional intake may have upon tooth erosion or helping to prevent it.

The ill-effects of brushing suggested by the Daily Mail was not part of this study. The researchers only suggested that excessive brushing to remove red wine stains can remove further tooth enamel. Thoroughly brushing your teeth with a soft toothbrush and flossing twice a day, in addition to regular dental check-ups, is the best way to keep teeth healthy.

Where did the story come from?

Brita Willershausen and colleagues from the Department of Operative Dentistry and Department of Geoscience, Johannes Gutenberg University, Germany, carried out this research, funded by the university’s medical faculty. The study was published in the peer-reviewed medical journal Nutrition Research.

What kind of scientific study was this?

This was a laboratory study that aimed to assess and compare how red and white wine erode tooth enamel, a process which removes minerals from the tooth surfaces.

In the study, the researchers used clean healthy human teeth extracted from 25 men and women aged between 40 and 65. Teeth with any defects or signs of existing erosion were not included in it.

The researchers selected 12 wines from a selection of 50 white and 50 red European wines, chosen to represent a range of acidity levels. Two whites and two reds were used to soak the teeth for four, six, 18 and 24 hours to look at the time-dependent erosion of the teeth. A further four whites and four reds were used to soak the teeth for 24 hours.

Special laboratory equipment assessed the amount of calcium released from the teeth, the depth into the tooth that calcium was lost from and the roughness on the surface of the teeth.

What were the results of the study?

The research found that the release of calcium was dependent on the length of time that the teeth were soaked in wine for. After 24 hours, significantly higher amounts of calcium were released from teeth soaked in white wine than from teeth soaked in red. They also noted that when teeth were soaked in white wine, calcium was lost from a greater depth into the tooth.

However, the teeth had similar surface roughness when soaked in either white or red wine. Wines with a greater acid content caused greater erosion.

What interpretations did the researchers draw from these results?

The researchers conclude that their study has demonstrated that white wines are more likely than reds to erode teeth, and that frequently drinking white wine may lead to severe dental erosion.

What does the NHS Knowledge Service make of this study?

This study soaked a number of extracted teeth in different wines for prolonged periods of up to 24 hours and found that white wines caused more tooth erosion and calcium loss than red. There are several limitations to this study:

• The laboratory situation does not represent real life as teeth would never be soaked in wine for such prolonged periods, and people would normally only hold wine in the mouth for a few seconds at a time (with the possible exception, as the researchers say, of wine tasters).
• It cannot be assumed that white wine alone is corrosive and harmful to teeth. Sugary soft drinks, fruit juices, liquors or spirits were not tested and could give similar, if not worse, results.
• The eight wines were specifically selected for their pH values from a selection of 100 European wines. Although it is likely that other wines can have the same effect, this cannot be assumed.
• The researchers speculate, based on previous studies, that eating calcium-rich foods such as cheese at the same time as enjoying a glass of wine may have some protective effect. This theory has not been studied here. As the study was carried out on extracted teeth in the laboratory, it is not possible to monitor the effects that saliva, diet and nutritional intake may have upon tooth erosion.

It is unclear why the newspapers claim that “brushing your teeth makes it worse”, as this aspect was not studied. The only mention close to this is in the closing paragraphs of their paper, where the researchers say that “excessive toothbrushing to prevent staining by red wines can further increase the loss of dental hard tissue”.

It would be wrong to interpret this as saying that if you are drinking white wine the best way to protect yourself from tooth erosion is not to brush your teeth at all. 

Thoroughly brushing your teeth with a soft toothbrush and flossing twice a day, in addition to regular dental check-ups, are the best ways to keep teeth healthy.