Tea is an important source of fluoride and the longer you leave it to brew, the better it is for your teeth.
That's according to new research about to be published. Tea scientist, study co-author and a member of the Tea Advisory Panel (TAP), Dr Tim Bond, says "Our findings underline the health benefits of tea. Drinks which are very sugary or acidic are a major cause of tooth decay and erosion, and they are often a factor in obesity, too, as we tend to focus on the calories we consume as food rather than those hidden away in drinks," he says.
"Tea does not damage dental enamel unlike sugary and carbonated drinks, acidic juice or alcohol. Instead, tea protects and strengthens teeth. In fact, it is estimated that 70 per cent of the average UK intake of fluoride comes in a cuppa."
Dr Bond and nutritionist Dr Carrie Ruxton tested three brands of black tea, selected to represent economy, mid-range and premium products. One tea-bag was brewed in 240ml of freshly boiled water and then allowed to brew before the bag was squeezed gently against the side of the beak and removed.
This process was repeated three times and the liquid was then combined before it was tested to obtain an average fluoride content for each tea and brew-time. Fluoride levels in all three teas increased with longer brewing times. This latest study adds to a growing body of evidence of the importance of tea for healthy hydration.
All forms of tea contain polyphenols, a family of plant compounds which appear to have antioxidant, anti inflammatory and anti-proliferative properties and recent research suggests that almost half the UK intake of flavonoids come from tea.
Dr Ruxton, dietitian and a member of the Tea Advisory panel points out "There is a lot of interest in flavonoids because there is now good evidence that they are associated with increased antioxidant activity, reduced lipid peroxide and improved resistance to oxidation of unhealthy LDL cholesterol."
However both Dr Ruxton and Dr Bond warn that scare stories about caffeinated drinks and questionable advice from people who call themselves nutritionists or nutritional therapists but have no reputable qualifications, have muddied the water when it comes health messages on hydration.
ln a recent review of hydration, Dr Ruxton highlights the flimsy basis for claims that the caffeine in coffee and tea could have a negative effect on hydration. She explains "This highly questionable advice is based largely on animal studies or human trials using high doses of caffeine pills rather than caffeinated drinks. And when it comes to tea there are actually only two trials which specifically examine the impact of tea on hydration - and neither found any problem at all."
There is now solid evidence, from a range of observational studies backed up by laboratory and human trials, to show that regular tea consumption is associated with a decreased risk of cardiovascular disease, type 2 diabetes, some cancers, neurodegenerative diseases and obesity.