Tart cherry juice had been in the news recently for its reported properties in ameliorating muscle soreness, and especially aiding sports people recover after intense exercise. Now it seems there is further evidence this fruit can also help improve the quality and length of sleep (Howatson et al., 2011). One suggested mechanism is to increase the levels of the sleep regulating hormone, melatonin.

The study, conducted in the School of Life Sciences at Northumbria University required 20 volunteers to drink two 30 ml servings per day, of either tart cherry juice (cv. Montmorency) or a placebo for a week. Their sleep and waking cycles were monitored using actigraphy which is a measure of movement, usually of the wrist where the monitor is placed. During sleep, the wrist movements are minimal and so provide a measure of whether the volunteer is asleep or not. Compared to a placebo, the sleeping time was increased by upto 25 minutes. Other notable benefits included improvements to sleep quality, measured as a 6% increase in a condition of ‘sleep efficiency’.

The researchers reported the presence of melatonin in the cherry juice itself although there is the inference of it also increasing melatonin levels in the body. The researchers had monitored melatonin levels in urine samples before and after the study and found that drinking the cherry juice increased urinary melatonin levels by up to 16% compared to the control sample. Drinking the juice might help those with jet lag, insomnia and working shifts if it improved their propensity for sleep. Earlier studies had also demonstrated how eating cherries helped improve natural sleeping (Garrido et al., 2010; Pigeon et al., 2010).

I’d be keen to know from other researchers as to whether other juices have the same impact benefit.

References

Garrido, M., Paredes, S.D., Cubero, J., Lozano, M., Toribio-Delgado, A.F., Munoz, et al. (2010) Jerte Valley cherry-enriched diets improve nocturnal rest and increase 6-sulfatoxymelatonin and total antioxidant capacity in the urine of middle-aged and elderly humans. J Gerontol A Biol Sci Med Sci 65: pp. 909-14.
Howatson, G., Bell, P.G., Tallent, J., Middleton, B., McHugh, M.P., Ellis, J. (2011) Effect of tart cherry juice (Prunus cerasus) on melatonin levels and enhanced sleep quality. Eur. J. Nutr. Oct. 30 Advanced notice
Pigeon, W.R., carr, M., Gorman, C., Perlis, M.L. (2010) Effects of a tart cherry juice beverage on the sleep of older adults with insomnia: A pilot study. J. Med. Food 13(3) pp. 579-83