Magazine article FDA Consumer

Beware the Unknown Brew: Herbal Teas and Toxicity

Magazine article FDA Consumer

Beware the Unknown Brew: Herbal Teas and Toxicity

Article excerpt

The old man of Vienna apparently found out what generations of herbal tea drinkers have discovered: that senna is a powerful laxative if taken in large amounts and that chamomile is a soothing relaxant that, among its many purported virtues, aids digestion.

Hopefully, though, the old man of Vienna was not allergic to ragweed. Because if he was, he might have had a reaction to chamomile tea--as did one 35-year-old American woman several years ago who when into anaphylactic shock after a few sips. Chamomile is a member of the same plant family as ragwee, asters and chrysanthemums, and people allergic to those plants had better be cautious of chamomile.

Herbal teas have been enjoyed for centuries throughout the world. But they have been the subject of controversy in the United States since their introduction into the mainstream marketplace two decades ago.

Comfrey, Lobelia and Sassafras

Comfrey tea has been implicated in liver disease, although only two such cases have been reported in the United States. In one instance, a 47-year-old woman developed a liver ailment after consuming up to 10 cups of comfrey tea a day and taking comfrey pills by the handful for more than a year in an attempt to cure her stomach pains, fatigue and allergies.

Although comfrey has enjoyed considerable popularity because of its supposed universal healing properties, there is reason to believe it is hazardous to health. Comfrey roots and leaves contain pyrrolizidine alkaloids, which have been found to cause cancer in rats. Celestial Seasonings, the industry leader in herb tea sales, dropped comfrey from its product line 10 years ago, and it was banned in Canada in 1989.

Lobelia tea can cause vomiting, breathing problems, convulsions, and even coma and death when used in large amounts. Lobelia, also called Indian tobacco, was used to treat asthma and bronchitis throughout the 19th century and experienced renewed popularity in the 1960s, when it was smoked by some young people to achieve a mild, legal "high." It supposedly produced the same feelings of mental clarity, happiness, and well-being when imbibed as tea.

In his book The Honest Herbal, pharmacognosist and former dean of the School of Pharmacy of Purdue University Varro E. Tyler says eating, drinking or smoking lobelia is "sheer folly." "Lobelia is pretty toxic. It's really not safe enough to use unless the dose is closely controlled," he says.

The Journal of the American Medical Association recently reported the case of a 25-year-old woman who developed abnormal menstrual bleeding as a result of drinking large amounts of "seasonal tonic," a homemade herbal brew. The woman was drinking the tea in an attempt to assuage her appetite so she could lose weight. The tea included a number of ingredients, three of which--tonka beans, melilot and woodruff--contain coumarin, an anticoagulant (blood thinner). The woman was also taking high doses of vitamins and other medicines that can intensify its effects of anticoagulants.

Aromatic sassafras tea, once popular as a stimulant and blood thinner and as a reputed cure for rheumatism and syphilis, causes cancer in rats when taken in large amounts. Oil of sassafras and safrole, major chemical components of the aromatic oil in sassafras root bark, were taken out of root beer more than 30 years ago. And sassafras bark was banned from use in all food. Safrole-free extract, however, is allowed in food.

Nevertheless, herbal teas are a commercial success. They are purchased for their aroma and flavor and as a supposedly healthy alternative to caffeine beverages. Some are bought as home remedies for their alleged medicinal benefits.

Since the 1960s, when they experienced renewed popularity as part of the back-to-the-earth and natural foods movements, consumption of herbal teas has steadily increased. Today, a half dozen other herbal tea manufacturers share the shelf with more traditional teas made from orange and black pekoe at the supermarket. …

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