Life-Cycle Studies: Toothpaste

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toothpasteFor the past five years, Worldwatch has explored the history, production method, and environmental and social impacts of everyday products - from chopsticks to pencils - in the Life-Cycle Studies section of its bi-monthly magazine, World Watch. This print-exclusive content is now available for free to Eye on Earth readers. Look for a new study every Friday!  

Overview

The toothbrush, in various forms, has long been well-regarded as the best tool for a healthy mouth. What to use with it, however, is a more complicated, at times toxic, tale.

The first recorded suggestion is from fourth-century Egypt, when a scribe wrote that a mixture of rock salt, mint, dried iris flower, and pepper formed a "powder for white and perfect teeth." Concoctions in the centuries since often included crushed coral or volcanic rock. These powders removed stains and tooth enamel equally well. Soap-based pastes replaced powders in the late nineteenth century, though with little improvement. Columbia University chemist William Giles, an early-twentieth-century researcher, described the pastes as "hard and sharp enough to cut glass." One 1930s product, Tartaroff, contained 1.2 percent hydrochloric acid; a single application could destroy 3 percent of a tooth's enamel, according to James Wynbrandt's Excruciating History of Dentistry.

By the 1940s, consumers were brushing with the kind of toothpaste used today. A chemical cocktail polishes, strengthens, and defends teeth from the day's invasion of bacteria. Ingredients typically include fluoride to prevent decay, triclosan to prevent infected gums, sodium pyrophosphate to remove tartar, and saccharin to please the taste buds. More than 356 million kilograms of toothpaste was traded in 2006.

Impacts

With every mouthful of toothpaste spat down the drain, a mix of questionably problematic chemicals flows into rivers, lakes, and oceans downstream.

Some researchers are concerned that triclosan, an antibiotic, may become so prevalent that bacteria found in the environment and humans will develop resistance. (Research has so far been inconclusive.) A recent study has also shown that low-level exposure to triclosan can disrupt the common North American bullfrog's hormone system.

Sodium pyrophosphate removes minerals that develop in saliva after meals, thus preventing tartar build-up. But it contains phosphorus, and while its role is minor compared to fertilizer runoff, toothpaste contributes to excessive algal growth in waterways. Decomposing algae suck the oxygen out of the water, killing off marine life and creating huge "dead zones." A recent Science study found more than 405 of the zones worldwide, up from 49 in the 1960s.

Apart from isolated contaminants such as the toxic diethylene glycol introduced into Chinese-made products in 2007, toothpaste's most controversial ingredient by far is fluoride. Naturally found in rocks and groundwater, fluoride was first added to toothpaste in 1914 to prevent tooth decay. Its addition is considered the single most important reason for the developed world's reduced incidence of cavities since then.

The cause for controversy is the well-intentioned public health officials who, since 1944, have mixed fluoride into drinking water. Opponents say the 210 million people worldwide with access to fluoridated water are overexposed because toothpaste already provides them with enough. The risks include severe tooth stains and increased chance of bone fractures, according to the U.S. National Academies of Science. In Western Europe, 17 of 21 countries have either refused or discontinued fluoridation.

Alternatives

Since the China incident, natural and organic personal care products, including toothpaste, have been selling at higher rates than their traditional counterparts. Natural products replace plaque removers with calcium carbonate, tartar controls with zinc, and artificial sweeteners with peppermint leaves. Fluoride is either omitted entirely or its concentration is lower than in conventional toothpastes. Global sales approached $7 billion in 2007 and may surpass $10 billion by 2010, according to Organic Monitor research. As evidence of the trend: Colgate three years ago purchased leading natural company Tom's of Maine for $100 million.

Ben Block is the staff writer for World Watch. He can be reached at bblock@worldwatch.org.

For permission to republish this article, please contact Juli Diamond at jdiamond@worldwatch.org.