Many are aware of the health benefits of drinking tea. Tea comes from the tea plant, Camellia sinensis. Brewed black tea is rich in polyphenols and antioxidants. According to webMD, tea contains “10 times the polyphenols found in fruits and vegetables.” There is also evidence that regular tea drinkers have less heart disease and stroke, lower total and LDL cholesterol, and recover from heart attacks faster. Some suggest that tea may help fight ovarian and breast cancers. For more information on the antioxidants in tea click here.
Here is also a recent post discussing some interesting benefits tea may have to gene expression.
I have come across a number of articles in the news lately about people who regularly consume a large amount of iced tea suffering from kidney problems relatively early in life. Here is a link to one such story (click here). The concern here is the amount of oxalates in brewed tea and its potential link to kidney stones. Most research suggest that consuming certain foods and drinks high in oxalates does increase your risk for kidney problems (specifically kidney stones). The amount of increased risk is a little less conclusive but it probably also has to do with other factors like the presence of bacteria that can degrade oxalate, the transit time of food through the intestinal tract, and the inheritance of certain genes. Having said that, according to The Children’s Medical Center of Dayton’s website (www.childrensdayton.org) an 8 ounce glass of tea contains about 18mg of oxalate. People who have a history of kidney stones and are put on a low oxalate diet by their physician are usually recommended to keep their oxalate consumption under 50mg per day, so consuming too much iced tea would definitely put you over this threshold. As far as people who do not have a personal or family history of kidney issues, it is unclear how much oxalate is safe to consume each day. One thing that is known is that calcium found in foods like dairy products binds to oxalate and keeps it from entering the blood, and then the urinary tract, where it can form stones (according to the NIDDK). Most kidney stone prevention diets recommend 800-1200mg of calcium per day from sources like milk and yogurt. Other food that are high in oxalates are spinach, rhubarb, beets, nuts, chocolate, wheat bran, strawberries, peanuts, and almonds.
Sweetened and flavored teas can be as acidic as soda, which can definitely have detrimental effects on the health of one’s teeth. But as you know, I am mostly concerned with unsweetened black tea. Brewed black tea is a much weaker acid than soda and juices, but it is still slightly acidic. Having said that, studies which have been done by the Academy of General Dentistry have come to the conclusion that tea has an “erosive effect” on teeth “similar to that of water, which has no erosive effect.”
Just like many of the other foods and beverages we consume on a daily basis, tea has the potential to stain our teeth. Some say that tea causes teeth to stain worse than coffee because of its high tannin content. To prevent this teeth staining, the best thing to do is to have good oral hygiene, consisting of regular brushing, flossing and visiting your dentist. Also drinking tea through a straw will reduce the amount of staining by reducing the direct contact the tea makes with your teeth. Over the counter whitening strips or gels, or professional materials dispensed by a dentist can also be helpful in reducing the teeth stains that are already present.