Dangers of Dieter's Teas

by Food and Drug Administration (FDA)

A cup of hot herbal tea may feel soothing to the soul, but instead of soothing the body, some herbal teas can make you sick.

This is especially true with so-called dieter's teas, herbal teas containing senna, aloe, buckthorn, and other plant-derived laxatives that, when consumed in excessive amounts, can cause diarrhea, vomiting, nausea, stomach cramps, chronic constipation, fainting, and perhaps death.

In recent years, FDA has received "adverse event" reports, including the deaths of four young women, in which dieter's teas may have been a contributing factor.

As a result, FDA is advising consumers to follow package directions carefully when using dieter's teas and other dietary supplements containing senna, aloe, and other stimulant laxatives. Consumers should seek medical attention for persistent diarrhea, abdominal cramps, and other bowel problems to prevent more serious complications.

The agency may consider requiring manufacturers to place a warning about the products' potential side effects on the products' labels. Some manufacturers already are doing so voluntarily.

These products — bought in health food stores and through mail-order catalogs, for example — often are used for weight loss based on some consumers' belief that increased bowel movements will prevent absorption of calories, thus preventing weight gain. However, a special committee of FDA's Food Advisory Committee concluded in 1995 that studies show that laxative-induced diarrhea does not significantly reduce absorption of calories. This is because the laxatives do not work on the small intestine, where calories are absorbed, but rather on the colon, the lower end of the bowel.

Juice drinks and tablets also may contain stimulant laxatives. FDA usually regulates these products as foods under the Federal Food, Drug, and Cosmetic Act. If the products are represented as dietary supplements, they are regulated under the Dietary Supplement Health and Education Act of 1994.

Stimulant Laxatives

The stimulant laxative teas and dietary supplements FDA is most concerned about contain one or more of the substances senna, aloe, rhubarb root, buckthorn, cascara, and castor oil. These plant-derived products have been used since ancient times for their ability to promote bowel movements and relieve constipation. Several, such as cascara, senna and castor oil, also are available as over-the-counter drug laxatives and are regulated as drugs.

Some of these substances also are used in much smaller quantities as natural flavorings in other foods. As such, they are regulated by FDA as food additives or "generally recognized as safe" substances. FDA has not received any information suggesting that these substances pose a hazard when used in the amounts normally needed to provide flavoring.

Except when used solely as flavorings, the names of these plant substances appear in the ingredient list on the label of these products. Dieter's teas and similar products often list the substances at or near the top because they often are the main ingredients. FDA proposed in December 1995 to require manufacturers to declare dietary ingredients, including proprietary blends, in descending order of predominance by weight on product labels. In the proposed rule, the substance would have to be given by its common or usual name: for example, Tinnevelly senna followed by its Latin name, Cassia angustifolia.

Most consumers who use dieter's teas and similar products know that the products have laxative properties, according to health professionals familiar with the products, even though the product labeling does not specifically state the term "laxative." Instead, the labeling may promote the product as a natural bowel cleanser. Sometimes it may not reflect the laxative qualities at all.

The product labels may not directly state that the products are for weight loss, although some allude to it. For instance, some products use the terms "dieter's," "diet," "trim," or "slim" in their names. Others may carry information on weight-loss practices, mentioning consumption of the product along with the weight-loss practices. Some of the teas are labeled as "low-calorie." Unless sweetened, they provide essentially no nutrients and no calories.

According to Ara DerMarderosian, Ph.D., professor of pharmacognosy (study of medicinal products in their crude, or unprepared, form) and medicinal chemistry at the Philadelphia College of Pharmacy and Science, users favor the products because they believe that the products may cost less and taste better than over-the-counter laxatives and because they are easy to buy. In addition, he said, people with eating disorders, such as bulimia and anorexia nervosa, may like the products because they act quickly and produce loose, watery stools. Unfortunately, this practice is not only useless for losing weight but can be dangerous for people on severely restricted diets.

Writing in the January 1996 American Druggist, DerMarderosian and his colleague Sharon Brudnicki, a registered pharmacist also with the Philadelphia College of Pharmacy and Science, noted that some users like dieter's tea and other stimulant laxatives for their purported "body cleansing" ability.

DerMarderosian was a member of the FDA Food Advisory Committee's 1995 special task group on stimulant laxative substances in food.

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