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Caffeine Sources Shifting

Coffee is still the top choice for fulfilling caffeine cravings, but a new study suggests that Americans' caffeine sources may be shifting.

Researchers found that soft drinks have surpassed tea as the second leading source of caffeine for adult men and women while remaining the top source of caffeine for children.

With the proliferation of coffee shops on every corner, it's no surprise that the study shows that more Americans of all ages are getting a caffeine buzz, with nearly 90 percent of adults and 76 percent of children getting caffeinated on a daily basis.

But researchers also suggest that the strength of that buzz may be waning as the average daily intake of caffeine per person is on the decline.

In the study, which appears in the January issue of the Journal of the American Dietetic Association, researchers analyzed common sources of caffeine in the diet of a representative sample of the U.S. population that was surveyed from 1994 to 1996 and in 1998.

Caffeine is found in beverages such as coffee, tea, and soft drinks, but it is also found in lesser amounts in some foods like chocolate. Other sources of caffeine, such as energy beverages, caffeinated water, herbal supplements, and medications were not included in this study.

Researchers found 87 percent of adults and 76 percent of children had caffeine in their daily diets, up from 82 percent of adults and 43 percent of children aged 6 to 17 years in 1977.

But while more people are getting a caffeine buzz, the strength of that jolt appears to be declining as the average daily intake of caffeine dropped from 227 mg per day to 193 mg per day in adults.

Among caffeine users, coffee (71 percent), soft drinks (16 percent), and tea (12 percent) were the top three sources of caffeine. Coffee was the main caffeine source for men and women over age 18, but soft drinks were the top caffeine source among children aged 2 to 17.

Among persons aged 2 to 54 years, as age increased, caffeine consumption increased.

An 8-ounce cup of brewed coffee has about 135 mg of caffeine, an 8-ounce cup of caffeinated tea has about 50 mg of caffeine, a 12-ounce glass of Coca-Cola has about 34.5 mg of caffeine, and a 12-ounce Diet Coke has 46.5 mg of caffeine.

Researchers say many Americans may not realize how much caffeine they're drinking because manufacturers are only required to list caffeine as an ingredient on the food or drink label, while the Nutrition Facts label does not specify the amount of caffeine in the product.

In addition, beverages marketed as high-energy drinks may contain more than one type of caffeine extract, and herbal sources of caffeine may not be listed as an active ingredient.

SOURCES: Frary, C. Journal of the American Dietetic Association, January 2005. News release, American Dietetic Association. WebMD Medical News: "Coffee and Pregnancy: A Bad Mix?"

By Jennifer Warner, WebMD Medical News
Reviewed by Brunilda Nazario, MD
© 2004, WebMD Inc. All rights reserved

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