Cherry juice may help older people with insomnia

A drink of tart cherry juice in the morning and evening may help people sleep better at night, according to a new study.

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.

Their findings were presented at a recent annual meeting of the American Society of Nutrition, held in conjunction with the Experimental Biology 2014 meeting in San Diego.

Insomnia is a common health problem among older adults, affecting from between a quarter to a third of the population aged 65 and older. Long-lasting sleeplessness can seriously affect health, especially in older people.

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 Dr Frank Greenway, co-author of the research, who said: “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 studied seven adults with an average age of 68 who suffered from insomnia and asked them to drink cherry juice twice a day for two weeks. The participants then consumed a placebo beverage for a further two weeks.

Dr Greenway and his colleagues studied their slumber in a controlled setting, using overnight polysomnography (a comprehensive recording of the biophysiological changes that occur during sleep) to evaluate such things as sleep onset and duration.

The researchers found that those who drank an 8-ounce glass of 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 investigate if the benefits were due to the melatonin content or another component in Montmorency tart cherries.

As a result of their research, the team now 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 that degrades tryptophan. Tryptophan degradation is a known predictor of insomnia and is also related to inflammation, said the report.

“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,” Dr Greenway says. “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 contributes to the sleep benefits. The report concludes 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.