It is also true that given the selected sample of healthy
elderly individuals with insomnia, these findings may not
generalize to other populations. Moreover, this cohort suffered
primarily from sleep maintenance insomnia and had
modest sleep onset difficulties, so it is most prudent to
consider the effect of tart cherries on SL to be undetermined
as there was a floor effect in this sample. In addition, the
cherry juice used in this study was a proprietary blend
(CherryPharm, Inc.) made from fresh tart cherries so that
findings may not generalize to cherry juice made from
concentrate or to eating 1–2 servings of tart cherries per day
(as participants ingested the equivalent of approximately
100 cherries per day).
Finally, this study was not designed to address mechanism
of action. If the mechanism for sleep enhancement is
melatonin, perhaps anecdotal reports of sleep improvements
by college and professional athletes is related to circadian
regulation of sleep afforded by melatonin. This is a testable
hypothesis. Similarly, a study undertaken with the study
beverage in a population with diagnosed circadian rhythm
disturbances would be informative. Alternatively, given that
several pro-inflammatory cytokines are involved in the
regulation of sleep,9 the anti-inflammatory properties of tart
cherries may be a mechanism of action.
In conclusion, the results of this study suggest that the
particular TCJ blend used in this study has modest beneficial
effects on sleep in older adults with insomnia. Given that
these results were achieved following only a brief treatment
period (2 weeks), that mechanism of action is unknown, and
that optimal dosing strategies (amount, time, frequency, and
duration) are equally uncertain, further study of the sleeppromoting
effects of tart cherries is warranted