The Trouble With Tea

America is a nation of tea drinkers. According to recent estimates, we consume about three billion gallons of the brew annually.

Tea, which is made by steeping the air-cured (black) or fresh (green) leaves of the camellia sinensis plant in boiling water, is often touted as a healthy alternative to everything from liquor to soda. While it has its health benefits, this popular beverage contains several ingredients, which in very large amounts, could actually harm your health. Below, we've listed a few to be aware of.

Caffeine: One eight-ounce cup of tea contains anywhere from 30 to 120 mg of caffeine. "A little cup of black tea may not seem like a big deal, but if you're sensitive to caffeine's effects, it can wreak havoc on your system," says Andrea Moss, a New York City-based certified holistic nutrition coach. "And 'how much is too much?' can really differ from person-to-person," she adds. Moss says many people experience:

  • Physical and psychological addiction
  • Interrupted sleep and insomnia
  • Increased risk of restlessness and anxiety
  • Uneven energy levels

More specifically, according to the National Institutes of Health, the caffeine in black tea may also:

  • Limit calcium absorption
  • Increase blood pressure in individuals with hypertension
  • Exacerbate symptoms of Irritable Bowel Syndrome (IBS)
  • Increase eye pressure in glaucoma patients
  • Interfere with certain medications

Tannins: The organic compounds that give tea its astringency, tannins reduce the body's ability to absorb iron, a necessary mineral. For people with iron deficiency anemia, who lack of healthy red blood cells, tea can worsen the condition. Iron deficiency anemia can be debilitating, causing weakness, exhaustion, headaches, and shortness of breath.

Fluoride: Tea contains a moderate amount of fluoride—between one and nine mg, or milligrams in about four cups. This common mineral is typically eliminated from the body by the kidneys, but heavy tea drinkers—for instance, people regularly consuming more than 20 mg of fluoride per day—could be at risk for skeletal fluorosis, in which excess fluoride forms deposits on the bones, causing pain and damage in the bones, joints, and teeth.

Oxalates: Oxalates are molecules common in plants like spinach and chard as well as in chocolate and nuts. Excess oxalates in the diet can contribute to the formation of kidney stones, a potentially painful condition that may require surgery. Tea, which recent studies estimate contains more than 15 grams of oxalates per cup, is considered high in oxalates. Adding milk to tea may help prevent oxalate absorption, however.

Aluminum: This metal is commonly found in soil—and in varying concentrations in tea plants. While tea drinkers are highly unlikely to obtain dangerous amounts of aluminum through the beverage, aluminum can easily accumulate throughout the body (in our kidneys, liver, brain), and produce high levels of oxidative stress—especially in the central nervous system, says Moss. Furthermore, she says, "the metal has been associated with increased risk of nervous system disorders, such as Parkinson's and Alzheimer's diseases, and has also been shown to inhibit calcium absorption, which can lead to mineral loss in our bones and an increased risk of osteoporosis."

A Word to the Wise

While drinking excessive amounts of tea can lead to health issues, moderation will go a long way towards limiting your risk of problems like fluorosis. For most people, one cup of Earl Grey, English Breakfast, or plain orange pekoe (that's Lipton and Tetley) is fine; just don't overdo it. If you want to avoid caffeine-laden teas: "Herbal tea is a great alternative," says Moss. "Without having to worry about caffeine's stimulating effect, you can drink herbal tea throughout the day and close to bedtime, without worrying about it keeping you awake."

Alison Massey, MS, RD, LDN, CDE reviewed this article.



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