Researchers from Louisiana State University in the US found that drinking Montmorency tart cherry juice twice a day for two weeks helped increase sleep time by nearly 90 minutes among older adults with insomnia.
These findings were presented at the annual meeting of the American Society of Nutrition, which is being held in conjunction with the Experimental Biology 2014 meeting in San Diego.
Insomnia is a common health problem among older adults, impacting an estimated 23 to 34 percent of the population ages 65 and older. Insomnia – defined as trouble sleeping on average more than three nights per week – can be an annoyance for some, but long-lasting sleeplessness can seriously affect health, especially in the elderly.
Insomnia is linked to a higher prevalence of chronic pain, high blood pressure, type 2 diabetes and a decline of cognitive function, or dementia. Individuals with insomnia may turn to sleeping pills.
This medication can also lead to further problems according to Frank, L Greenway, co-author behind the research.
‘Sleeping pills may be an option for younger insomniacs, but for older people these medications quadruple the risk of falling, which can lead to broken hips and, often, earlier death.’
Researchers studies seven adults with an average age of 68 who suffered from insomnia and asked them to drink cherry juice twice a day over two weeks.
Later, the same group took a placebo drink.
Dr Greenway and his colleagues studied their slumber in a controlled setting, using overnight polysomnography to evaluate sleep efficiency, such as sleep onset and duration.
Participants also completed questionnaires related to sleep, fatigue, depression and anxiety. Additionally, blood work was conducted on each participant.
The researchers found that those who drank the Montmorency tart cherry juice in the morning and at night were able to sleep more than an hour longer each night (averaging 84 minutes) compared to the placebo, and their sleep tended to be more efficient.
Montmorency tart cherries are a natural source of melatonin, a hormone that helps regulate the sleep-wake cycle. While previous studies have suggested that tart cherry juice has sleep-enhancing benefits, Greenway and colleagues set out to help explain why.
They wanted to understand if the benefits were due to the melatonin content or another component in Montmorency tart cherries.
They believe the ruby red pigments in tart cherry juice, known as proanthocyanidins, also play a role.
These natural polyphenolic compounds are especially abundant in Montmorency tart cherries. In the study, tart cherry juice helped to increase the availability of tryptophan, an essential amino acid and a precursor to serotonin that helps with sleep.
The juice was shown in cells to inhibit an enzyme (indoleamine 2,3 dioxygenase) that degrades tryptophan.
Tryptophan degradation is a known predictor of insomnia and is also related to inflammation, said co-authors Jack Losso and John Finley, professors in the School of Nutrition and Food Sciences at Louisiana State University Agricultural Center.
‘Even though the amount of tryptophan in tart cherry juice is smaller than a normal dose given to aid sleep, the compounds in tart cherries could prevent the tryptophan from breaking down so it’s able to work in the body more effectively,’ Greenway explained.
‘These compounds may help to improve tryptophan bioavailability for serotonin synthesis, which could have a positive effect on sleep. Increasing serotonin also helps improve mood and decrease inflammation.’
Greenway believes it’s the unique combination of melatonin and tryptophan in Montmorency tart cherries that is likely contributing to the sleep benefits. He and his colleagues conclude that drinking a glass of tart cherry juice in the morning and the evening may be a better and a safer way to treat insomnia.