Q: Can chamomile tea promote sleep?
A: Despite the fact that tea made from chamomile (usually Matricaria chamomilla, known as German chamomile) has been used as a sleep aid for centuries, there is little solid research supporting its effectiveness. The few human studies on chamomile tea or supplements have methodological problems, such as lack of an appropriate control group.
For instance, a Taiwanese study in the Journal of Advanced Nursing in 2015 involved 80 women who had recently given birth and had trouble sleeping. Half were given German chamomile teabags and told to drink a cup of tea a day, while the other half got no treatment. After two weeks, they filled out a sleep questionnaire, which showed that the chamomile group had some improvements in sleep quality and reduced postpartum depression compared to the control group. But there was no placebo comparison group.
Some studies have used chamomile supplements and compared them to placebo (dummy) pills. In a 2011 study in BMC Complementary and Alternative Medicine, 17 people with insomnia were given tablets containing chamomile extract (a higher dose than in tea) or a placebo twice daily for 28 days. Their sleep diaries showed no significant or consistent benefit for any aspect of sleep. In fact, the placebo group had longer sleep time.
In contrast, an Iranian study in the Journal of Education and Health Promotion in 2017 looked at 77 older people in nursing homes, giving them chamomile capsules twice a day or no capsules for four weeks. Based on a questionnaire, the researchers found a significant improvement in sleep quality in the chamomile group. Again, there was no placebo comparison group.
It’s not clear how chamomile might affect sleep. Lab studies suggest that certain flavonoids in the herb may affect neurotransmitters in ways that could reduce anxiety and thus possibly aid sleep. But how much of these compounds end up in a cup of tea or capsule is not known. It’s also likely that the warmth and aroma of the tea help some drinkers relax, and that the expectation of benefit may produce a placebo effect.
While chamomile is “generally recognized as safe” (GRAS), there’s little information on its safety during pregnancy. Thus, pregnant women should drink it only in moderation and consult their health care providers about any herbs or supplements they may take. People allergic to ragweed may also be allergic to chamomile, since they are both in the daisy family (Asteraceae).
This article first appeared in the UC Berkeley Wellness Letter.
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