Caffeine levels in dietary supplements commonly used by military personnel are often incorrectly labeled, according to a recent study conducted by NSF International, Harvard Medical School and the Uniformed Services University. The study, which was published in the Journal of the American Medical Association Internal Medicine last week, looked at 31 of the most popular dietary supplements sold as capsules on military installations. Samples from the supplements were analyzed for caffeine content per serving and compared against what was listed on the product label. NSF International, an independent public health organization specializing in the testing of nutritional supplements among other products, conducted the analysis.
The study found that the caffeine content in supplements is inconsistent and often times inaccurate:
- Of the 20 dietary supplement products that listed caffeine on the label, 6 products (30 percent) failed to state the amount of caffeine on the label. These products contained high amounts of caffeine, ranging from 210 to 310 mg per serving. To put this in perspective, an eight-ounce cup of coffee has approximately 100 mg of caffeine.
- 5 of the 20 products (25 percent) were inaccurately labeled containing a dose of caffeine that was at least 10 percent more or less than the labeled amount.
- Only 9 of the products (45 percent) listed an accurate amount of caffeine on the label.
"This study highlights the inconsistent labeling practices of many dietary supplement manufacturers. Many of the supplements tested failed to provide clinically accurate and useful information about caffeine content," said Ed Wyszumiala, general manager of the Dietary Supplement Certification Programs at NSF International. "It is common for military personnel and general consumers to drink other caffeinated beverages, like coffee, soda and energy drinks, throughout the day. Without accurately knowing the caffeine content in a supplement, people run the risk of consuming unhealthy levels of caffeine."
"Studies like this highlight the need for more testing of supplements," said Wyszumiala. "This is why NSF International developed an American National Standard for testing dietary supplements so consumers can look for products that are tested and certified to ensure what’s on the label matches what’s in the bottle and there are no unacceptable levels of contaminants."
Caffeine intake in the form of energy drinks is common practice in the military. A recent study from the Centers for Disease Control and Prevention found that 45 percent of service members consume energy drinks on a daily basis. Yet, federal law does not require that these drinks list caffeine content on the label.
The NSF International/Harvard/USU study also looked at herbal ingredients in dietary supplements that are known to naturally contain caffeine to understand if the caffeine content was properly disclosed on the supplement label. Findings revealed that 11 supplements listed an herbal ingredient that naturally includes caffeine but did not list “caffeine” on the label.