Caffeine Source Reference
Tracking caffeine information is a pretty obsessive thing to do. That’s why we’re quite obsessive about getting it right.
For many popular brands, the information was obtained from the brand the website, from the nutrition label, or from communicating directly with the beverage manufacturer. Note that there seems to be plenty of “one-upmanship” between manufacturers - and we sometimes suspect that the manufacturer may overstate caffeine amounts.
To check the source, go to the caffeine database and click on the item. This will take you to a detailed page. At the bottom of the page the sources are listed.
For more generic items we have also consulted with a number of different research articles:
[1] 2006 USDA Nutrition Database SR19 (link)
[2] Bunker and McWilliams; J. Am. Diet. 74:28-32, 1979
[3] Caffeine Content of Specialty Coffees, Journal of Analytical Toxicology, October 2003, vol. 27, no. 7, pp. 520-522. McCusker R.R.; Goldberger B.A.; Cone E.J. (link). Also a summary here.
[4] The old caffeine FAQ - rather dated now (link). Much of the information presented there came from the Bunker and McWilliams (1979) paper.
[5] Food and Chemical Toxicology, Volume 34, Issue 1 , January 1996, Pages 119-129 J. J. Barone and H. R. Roberts
(link)
[6] The American Beverage Association - they published the caffeine content of all soft drinks from member brands. However, when they revamped their website (now Ameribev.org) the caffeine information mysteriously disappeared. Fortunately we have a cached copy of it.
[7] Virtually all caffeine content tables on the web seem to be sourced from a CSPI Nutrition Action Health Letter here. This letter dates from 1996 and yet some of the caffeine information can only have been entered after this date. Some of the Starbucks caffeine figures seem very dubious (only 35 mg for a shot of espresso?). CSPI in turn quote a few other sources - but none of these other sources have any Starbucks information.
[8] Journal of Analytical Toxicology, Volume 30, Number 2, March 2006, pp. 112-114, McCusker, Rachel R.; Goldberger, Bruce A.; Cone, Edward J. (link) See also PDF.
[9] Supplements containing caffeine (USDA). (link)
[10] Caffeine Content of Decaffeinated Coffee. Journal of Analytical Toxicology, October 2006, vol. 30, no. 7, pp. 611-613. McCusker R.R.; Goldberger B.A.; Cone E.J. The University of Florida has undertaken lab testing of popular decaf coffees (see here).
[11] Consumer Reports - Analyzed caffeine in a number of items (link).
[12] Actions of Caffeine in the Brain with Special Reference to Factors That Contribute to Its Widespread Use. Pharmacological Reviews, Vol. 51, Issue 1, 83-133, March 1999 Bertil B. Fredholm1, Karl Bättig, Janet Holmén, Astrid Nehlig and Edwin E. Zvartau - Fascinating research into the use of caffeine (link).
[13] An exhaustive review of individual response to caffeine. This research (undertaken by Australia and NZ government) looks at dozens of studies and attempts to measure reaction to caffeine based on quantity (link)
[14] Caffeine Content of Prepackaged National-Brand and Private-Label Carbonated Beverages. Journal of Food Science; K.-H. Chou and L.N. Bell. A large test of many popular soft drinks. link
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