Troops who take dietary supplements to lose weight or get ripped may be getting more caffeine than is healthy, according to a new study published online Monday at JAMA Internal Medicine.
Chemical analysis of 31 popular supplements sold on military bases that contain caffeine showed that fewer than half accurately listed caffeine content, with some products containing more caffeine than five 12-ounce Mountain Dews.
Although the study did not name the products tested, the research is important, author Dr. Pieter Cohen said, because service members who use supplements likely also consume caffeine from coffee, energy drinks and food and may be getting too much of a good thing.
"Caffeine is extremely safe in the amounts found in food, and research has showed with low to moderate doses, your performance — increased vigilance and decreased reaction time — is better. But like any drug or medication, get too much of it, and the benefits decrease. At high doses, you are going to have side effects," Cohen said.
Cohen, an assistant professor at Harvard University and internist at Cambridge, Mass., Health Alliance, teamed with other researchers, including Patricia Deuster with the Uniformed Services University Consortium for Health and Military Performance, on the research.
The group looked at the caffeine content of the 31 top-selling supplements sold at installation exchanges that either listed caffeine as an ingredient or likely contained it, based on other ingredients on their labels.
Most were weight-loss or workout enhancement supplements, and one was marketed as a multivitamin, Cohen said.
Of the 20 products that listed caffeine on their labels, nine contained accurate amounts, according to the researchers, although "accurate" meant within 10 percent of the listed amount.
In one case, this meant the product, with a label noting it contained 400 mg of caffeine — 11 times the amount in a 12-ounce Coke — actually contained 435 mg of caffeine, or the amount found in 12 Cokes.
Five of the products contained far less (27 percent) or more (113 percent) caffeine than stated.
And six listed caffeine on their labels without any amount noted, as is allowed under Food and Drug Administration regulations. Those six all contained "high amounts of caffeine ranging from 210 to 310 mg per serving," according to the study.
"This is all legal and legitimate from a regulatory standpoint, but from a consumer standpoint, it's not helpful. The quantity of caffeine should be clearly stated on a label and needs to be accurate," Cohen said.
In December, FDA officials said they are reviewing the safety of energy drinks containing caffeine and other stimulants, to include an investigation of adverse reactions to energy drinks and shots as well as consultations with outside experts, according to the office of Sen. Richard Blumenthal, D-Conn.
In November, the FDA confirmed it had received reports of 13 deaths and 92 medical events associated with people who had taken the popular shot 5-hour Energy.
In October, the FDA also said it was investigating reports of five deaths among those who consumed Monster Energy drinks.
The reports of adverse health problems following consumption of these energy drinks does not imply that the drinks caused the problems or even contributed to them, however. It means only that consumers, physicians, medical facilities or the company itself notified FDA of a medical problem that occurred either during or after consuming the products.
Cohen said he looked at dietary supplements because he believes they are an overlooked source of caffeine for service members.
He advised troops to consume caffeine from only well-labeled sources, like caffeine pills, gum and sodas, all of which are regulated by the FDA.
"We don't want to throw caffeine under the bus. Caffeine is a safe, fantastic ingredient. … I would avoid supplements that list caffeine in any amount on their labels. Combining them with energy drinks or any other caffeinated product could be detrimental to your health," he said.