Health writer Patsy Westcott tries to sort the facts from the fiction of our body’s own sleep hormone.
Melatonin, aka the Dracula hormone (it only comes out at night) is a natural anti-oxidant manufactured by the pineal gland, a tiny pine-cone shaped structure nestled in the centre of the brain.
The philosopher Descartes believed the pineal gland to be ‘the principal seat of the soul’ dubbing it ‘the third eye’. In the 21st century, melatonin is considered to be ‘the key to the gate of sleep’, stimulated by fading light at dusk and quelled by the brightness of dawn.
According to the US National Sleep Foundation the melatonin cycle kicks off around 9 p.m. when the pineal gland is switched on by our body clock, causing a steady climb of melatonin in the bloodstream. Levels stay high for around 12 hours until sunrise when they begin to decline reaching barely detectable levels at around 9 a.m.
Even if your pineal gland is switched on, melatonin is not produced unless you’re in dim light. Both sunlight and artificial light can halt melatonin release. Note to self: tea lights and table lamps don’t just look better than a glaring central light – they could also help you sleep.
But that’s not all. Melatonin is also thought to have a wider role, which could explain why a good night’s sleep is so important for health. Research suggests that melatonin:
* may help preserve the function of the beta cells of the pancreas and so help prevent the development of type 2 diabetes
* may also help preserve bone mass, so protecting against osteoporosis
* may help protect the nerve cells against degeneration, so protecting against diseases such as dementia and Parkinson’s disease
* and may help protect against the development of breast cancer – one possible reason for the finding that night work can increase the risk of this disease.
Melatonin production tends to wane as we get older, possibly because of calcification of the pineal gland. In older people with insomnia levels of melatonin are lower and the time of peak production is also delayed.
Because we produce melatonin naturally it is considered a dietary supplement in the US and you can buy it over-the-counter in health shops. According to surveys around 2% of US adults (over 4.5 million people) use it to aid sleep.
In the UK, however, it’s only available on prescription in the form of a controlled release tablet for short-term treatment of ‘primary insomnia’ (i.e. insomnia lasting at least a month not caused by an underlying psychological or physical disorder or drug treatment) in over-55s. The Medicines and Healthcare Regulatory Agency cautions against unlicensed products from the States on the grounds that they may not meet manufacturing standards for medicines.
Supplementary melatonin is apparently most effective when there is little natural circulating melatonin. Dr Helen Burgess writing in the journal, Sleep, says, ‘Melatonin’s soporific effect is greater when it is taken during the biological day, as opposed to the biological night when (the body’s own) melatonin is secreted from the pineal gland.’ This is reflected in the US Sleep Foundation’s advice that, ‘Taking it at the “wrong” time of day may reset your biological clock in an undesirable direction.’
Nutrition expert Dr Marilyn Glenville cautions against buying melatonin supplements over the internet, saying, ‘Melatonin is a hormone and in my opinion, should be on prescription like any hormone medication. Taking it requires a judgement as to whether you need it, for how long and whether it causes an imbalance with other hormones because of the body’s feedback mechanisms.’
The good news is that controlling levels of stress can help to boost melatonin without the need to take a supplement. Says Dr Glenville, ‘The stress hormone, cortisol opposes the action of melatonin so if stress levels are high then the melatonin level can be inadequate.’