Can chamomile help promote sleep?
BACKGROUND
Chamomile is a common flowering plant that is indigenous to central and southern Europe. It is now cultivated around the world because it is one of the most popular herbal remedies on the market.
Chamomile is used as a remedy for several conditions, but one of its strongest reputations is as a natural sleep aid. For this, dried chamomile leaves and flowers are brewed as a tea or placed in a sachet under the pillow. Although a number of pharmaceutical drugs are available that promote sleep, they have side effects.
Many therefore turn to “natural” sleep aids. One recent study found that 18 per cent of Canadian adults use some form of “natural” sleeping aid, with chamomile being the most popular. This compared with about 12 per cent using prescription medications.
Several different species and remedies are called chamomile. The most commonly used medicinal plant is the German, or genuine, chamomile (Matricaria recutita).
Roman, or English, chamomile is an unrelated plant, with some of its related species also called chamomile.
To make matters more confusing, each plant has several different scientific and common names. Make sure any chamomile you might use is clearly labelled as containing Matricaria recutita.
EVIDENCE FROM STUDIES
Almost all the research published to date has been conducted on German chamomile.
Dozens of ingredients have been purified from the plant and have confirmed some traditional uses. A few animal studies have shown that chamomile can cause sleepiness and prolong sleep duration induced by other drugs. These effects appeared to be caused in similar ways to how Valium-like drugs (called benzodiazepines) have their effects.
However, clinical studies of chamomile for sleep are lacking. The only study investigating chamomile’s potential to induce sleep in humans was reported in 1981.
No control group was used, but after drinking a cup of strong chamomile tea, 10 of 12 hospitalised patients fell into a deep sleep lasting an average of 90 minutes.
In 2009 the results of the first controlled study of chamomile for mild to moderate generalised anxiety were published.
This study found significant reductions in anxiety levels among those taking chamomile extract capsules compared with placebo. Given that sleep problems are sometimes related to anxiety, this study provided some supportive evidence for chamomile’s traditional sleep use.
However, the authors cautioned that additional studies with larger numbers of people are needed to confirm these results.
In addition, the researchers used a specific pharmaceutical-grade product, standardised to give 220mg of extract. Other products and teas might not have the same effect.
PROBLEMATIC ASPECTS
Severe allergic reactions to chamomile are very rarely reported, usually in people allergic to other members of the daisy family. Skin reactions are the most common effects, whether chamomile is taken orally or applied to the skin.
Chamomile contains a small amount of natural blood-thinning agents, which might lead to addictive effects in people taking other blood-thinning medications. Since some studies suggest that chamomile acts in similar ways to benzodiazepines, it might have addictive effects with those medications also. However, serious problems have not been reported with chamomile.
RECOMMENDATIONS
In spite of the traditional use of chamomile for sleep problems, hardly any research has been conducted in the area. Evidence from laboratory studies is somewhat supportive of a beneficial effect. However, much further research is needed before chamomile can be recommended.
At the same time, its use appears to be safe, except for those with allergies to the daisy family. A trial period with chamomile may be helpful. Replacing a bedtime cup of tea with chamomile tea could be beneficial even if it just removes a late-night source of caffeine.
Dónal O’Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a Senior Lecturer in the School of Nursing, Dublin City University
