Black tea is the most popular beverage in the world, enjoyed by millions of people in numerous countries, including the Unites States. Research has indicated that black tea contains a number of potentially healthful compounds, including antioxidants. However, a recent study has revealed that black tea may be higher in fluoride than previously thought, thus making it a cause for concern for people who drink large quantities of the beverage.

Researchers stress that the fluoride that a person consumes when drinking two to four cups of tea every day poses no risk. However, heavy drinkers may want to give it some thought. This is because of the excess fluoride that would result from such consumption.

For years, black tea was believed to contain anywhere from one to five milligrams of fluoride per liter. Now, a new study has found that those numbers may need to be revised, and black tea my in fact contain as much as nine milligrams of fluoride.

While fluoride is known to help strengthen teeth, it can have potential adverse effects when taken in large quantities, and can even be toxic at high levels. Long term ingestion of excessive fluoride can also lead to bone problems.

On average, people consume about two to three milligrams of fluoride, which is considered a safe amount, every day through fluoridated water, toothpaste, and food. For significant problems to bone health to occur, a person would have to drink nearly 20 milligrams every day over the course of 10 years or more.

The current findings is the result of a study that looked at patients who were suffering from advanced skeletal fibrosis, a disease that is caused by excessive consumption of fluoride and results in damage to the bones and joints. Though the disease is very rare in this country, the one thing that linked all the of the patients was that they each drank about one to two gallons of tea every day over the course of 10 to 30 years.

After initially finding that the tea that they drank was low in fluoride, researchers began to wonder if some of the compound was not being detected. Traditional testing methods measure only the fluoride that exists in the leaves, but does not include the fluoride that is combined with aluminum to form aluminum fluoride.

By using an alternate method that takes the aluminum fluoride into account, scientists were able to determine that levels of fluoride were between 1.4 to 3.3 times higher in the most popular brands of tea.

The authors stress, however, that tea drinkers should in no way be discouraged from enjoying their favorite beverage, but to keep in mind that excessive consumption over the course of many years may warrant a bit of moderation.