Hidden sources of caffeine

FALLBROOK – Caffeine is a stimulant that untold millions, if not billions, of people across the globe insist they cannot go without. Whether it's in a morning cup of coffee or a midday energy drink, caffeine serves as a vital kickstart for individuals whose energy levels could use a boost.

Caffeine is often painted in a negative light, but such characterizations are misleading. The Mayo Clinic notes that up to 400 milligrams of caffeine per day appears to be safe for most healthy adults. Coffee drinkers know that certain cups of coffee are stronger than others, but the U.S. National Library of...