Lots of us have problems sleeping and it is one of the most common questions that doctors get asked about.
It is estimated that around half of adults have symptoms of insomnia occasionally and around 10 percent of people have experienced chronic insomnia. It is more likely to occur in women than in men and is more likely to affect the elderly. Insomnia is generally defined as having trouble sleeping, on average, more than three nights per week.
There are some steps that people who are affected can take in order to maximise their chances of sleeping well, what experts call “sleep hygiene”. These include not napping during the day; making sure the bedroom is dark and a comfortable temperature; reducing caffeine and alcohol intake and going to bed at a regular time.
Recent research has shown that relief may be available from, of all things, cherries. Specifically, tart or sour cherries, which are a variety of cherry that are grown worldwide and often used in cooking and in making fruit concentrates.
Tart cherries have high levels of chemicals called anthocyanins. These are a type of flavonoid which have strong antioxidant activity and anti-inflammatory effects. Of more relevance to sleep is the fact that they also contain a small amount of the sleep-regulating hormone melatonin.
Melatonin is a hormone found naturally in the body. Its main function is to regulate night and day cycles, also known as sleep-wake cycles. Darkness causes the body to produce more melatonin, which signals the body to prepare for sleep, whereas light decreases melatonin production and signals the body to prepare for being awake. As well as for sleep, people use melatonin to adjust the body's internal clock, for example, to help with jet lag symptoms or if they are working night shifts. It is also sometimes used by blind people in order to establish a day and night cycle. Something that is quite unique to melatonin is how it is viewed by regulatory bodies such as Medsafe in New Zealand or the FDA in USA. In New Zealand and in the UK you need to have a prescription from a doctor in order to obtain melatonin, but in the USA, you can buy it without a prescription from a health shop or a pharmacy.
As an example of the research behind using tart cherries for sleep, in a double-blind trial, healthy young people took 30mls daily of a tart cherry juice concentrate for seven days, estimated to contain the equivalent of 90-100 tart cherries. This resulted in increased urine levels of melatonin and an improvement in several measures of sleep quality. In another double-blind study of older people with insomnia, drinking cherry juice for seven days resulted in improvements in measures of sleep quality. In general, studies are finding beneficial effects on sleep from tart cherries that are around the same as those from taking the herbal product valerian or from taking melatonin itself, two products that have been shown to be effective for sleep.