Caffeine levels in drinks, snacks, and drugs

Caffeine is complicated. Moderate coffee drinking, once considered a vice (if a benign one), can reduce the risk of gallstones, Parkinson's disease, type 2 diabetes, and other health problems. Caffeine helps relieve pain when combined with acetaminophen or other painkillers. And modest amounts of the stimulant can improve alertness and cognitive performance.

But too much can cause jitters, difficulty concentrating, and sleep problems. And too much caffeine could be a problem for people with heart disease or osteoporosis.

It's not easy to know how much caffeine you're getting. Manufacturers don't have to disclose the amount in a product, just its presence, and only if the caffeine is added, as in colas or energy drinks. Caffeine that occurs naturally in chocolate or botanical ingredients such as guarana doesn't have to be mentioned.

We looked at beverages, snacks, and over-the-counter drugs that contain caffeine. All the drugs listed caffeine amounts, and it was easier to find caffeine content on beverage packages than on snacks.

Caffeine levels varied widely, from 12 milligrams in a 1.55-ounce bar of Hershey's milk chocolate to a pulse-revving 415 milligrams in a 20 fluid-ounce venti Starbucks Bold Pick of the Day. Diet Coke had more than Diet Pepsi (47 milligrams compared with 35 milligrams per 12-fluid-ounce serving), and that Venti Starbucks had 70 percent more caffeine than the same-size cup of Dunkin' Donuts regular coffee. Starbucks Trenta iced coffee (31 fluid ounces!) actually had much less caffeine than the 20-fluid-ounce hot coffee, possibly because the ice takes up so much space. Other differences: Dark chocolate had more caffeine than milk chocolate, and a 6-ounce container of Dannon coffee yogurt had the same caffeine content—30 milligrams—as just 4 ounces of Häagen-Dazs coffee frozen yogurt.

Bottom line. Most healthy adults can safely consume up to 300 milligrams per day; pregnant women, less than 200 milligrams; and children, no more than 45 to 85 milligrams, depending on age. Check labels or brand websites for actual quantities.