its effects on performance and immune response was partially supported by the Department of Defense (DoD), indicating the level of military interest in this dietary supplement. Likewise, although the frequency of use of tyrosine was not apparent, this amino acid has been of interest to the military and the object of research investigations to counteract the decrements in cognition that are associated with stress. Because of the reported use of weight-loss products, chromium was chosen as an example of a dietary supplement ingredient that is often found in such products. The known chronobiotic effects of melatonin may justify its use to ease the effects of jet lag as well as of long or night shifts, and therefore it was included for review. Similarly, valerian could be used for its alleged sedative properties and potential to alleviate sleep disorders, common in military life especially during demanding military operations that require long periods of wakefulness or unusual working shifts.
Details about the strategies used in conducting literature searches are described in Chapter 5. In general, the committee evaluated reviews that concentrated on safety and efficacy. For some dietary supplements (e.g., Gingko biloba), research on use is so broad and encompasses so many areas that the committee decided to focus the review on effects that would be of interest to the military (e.g., effects on cognition). This is especially recommended for those supplements that have already been extensively studied. Reviews of safety emphasized two areas: bioactivity and interactions with other dietary supplements or medications. For the latter, a list of the medications most frequently dispensed to active duty U.S. Army personnel was obtained from the DoD Pharmacy Operations Center, as a representation of typical medications used by military personnel. Although the committee was also asked to provide information on potential withdrawal effects, and the committee recognizes their importance, caffeine is the only supplement for which such information was found. The committee did not perform an evidence-based classification of original research on each supplement. As requested in the statement of task for this study and in accordance with the primary intent to identify supplements that pose serious concerns, the committee relied, as much as possible, on existing reviews by other authors to produce the summaries for each dietary supplement. If a review was not available for the last 10 years, original research was included. In those cases, limitations were noted where appropriate (see tables in Chapter 4).
Although the committee emphasized review of safety, the management of dietary supplements for the military needs to follow an evaluation of both risks and benefits, as the recommended framework notes. The reviews therefore also include information about benefits. When reviewing safety, effects judged to be especially pertinent to specific military subpopulations because of performance demands (e.g., cognitive or physical fitness), mission environments (e.g., high altitude, extreme temperatures), or the impact