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Chamomile Tea, Will You Help Me Sleep Tonight?

Chamomile tea is widely believed to help with sleep problems, but the scientific evidence is sparse. And it’s only been compared to drinking hot water… once.

We’ve all heard it: chamomile tea is what you drink if you have difficulty falling asleep. This bit of folkloric wisdom has been repeated so many times, it must be true, right?

One in three Canadians over the age of 15 has trouble falling into the arms of Morpheus or staying asleep. Chamomile tea, if it can pull off the spectacular feat of resolving this epidemic, would become an herbal hero. Chamomile is a type of plant that has a long, varied history of being used as a panacea, a supposed cure-all. It’s said to be a remedy for infections, like chickenpox and the common cold; for inflammation, like gingivitis; for neurological issues such as anxiety and insomnia; for ulcers, acne, diaper rash… basically, it seems chamomile was the medical duct tape of the pre-MacGyver days.

Now, anecdotes can be the spark that initiates scientific inquiry, but they should not be held as reliable evidence. So can science tell us if drinking chamomile tea will help you sleep?

I was able to find three randomized controlled trials that looked at the interplay between chamomile and sleep. The 2016 Chang & Chen trial in Taiwan randomized 40 women who had just given birth to drinking one cup of chamomile tea a day for two weeks, whereas another 40 postpartum women got nothing. While the tea group got better scores on their sleep questionnaires, that difference went away four weeks after they stopped drinking the tea. A year later, a different trial was published by Abdullahzadeh and colleagues, reporting on the positive impact of chamomile in the elderly, but it wasn’t from drinking tea. Researchers gave participants capsules containing 400 mg of chamomile, twice a day, while the control group received nothing. The influence of receiving some kind of treatment cannot be discounted: I wish both trials had used placebo drinks or placebo pills in their control group.

These positive signals are encouraging, but they must be contrasted with the findings of Zick and colleagues in 2011. Their patients received chamomile capsules twice a day for a month and also kept a sleep diary. This allowed the researchers to conclude there was no difference in how fast these patients fell asleep, or how much sleep they got (on top of many other sleep-related variables) when compared to participants receiving a placebo.

You may be wondering how much chamomile was in those pills. Zick et al. reported in their article that each daily dose represented 15 grams of chamomile flowers. They concluded that “this amount could not feasibly be delivered as a tea and could only be achieved using a concentrated extract.”

Although results so far have been somewhat disappointing, I’m not ready to write off chamomile entirely. You see, this herb is made up of over 120 different compounds, including apigenin which has an affinity for the same cellular receptors used by minor tranquilizers. Is chamomile the new Xanax?

A particularly thorough clinical trial was conducted in 2009 at the University of Pennsylvania known as “Chamomile Therapy for Generalized Anxiety.” The researchers excluded from the trial anyone who was already on anti-anxiety medication; the placebo pill bottles they gave participants had a drop of chamomile oil inside the lid to make it harder to tell to which arm of the trial participants had been assigned; and the data analysis itself was blinded. Such robust work yields confidence in the results, and the results were…  sure, there was a reduction in anxiety for people who got the chamomile pills, but the overlapping of anxiety scores with those of the placebo group leaves me a little disappointed. Moreover, the lower dose of chamomile was counterintuitively more poorly tolerated than the high dose, which makes me think the results are particularly noisy.

Given this underwhelming performance by chamomile, how can we explain that some people swear by its soothing properties? Drinking tea can’t be boiled down to the mere ingestion of molecules (pun intended). It’s often a ritual. We boil the water. We take out the fragrant tea pouch. We smell the tea as it steeps. We wrap our hands around the warm mug and drink a hot beverage. The ceremony itself calms us down. What I would like to see in the scientific literature is a comparison between drinking chamomile tea… and drinking hot water. (A Japanese study allegedly did just that and found that “relaxation scores increased after drinking either beverage.”)

In the meantime, we may discover interesting properties of specific compounds found in chamomile, such as apigenin. If these components are potent enough, and safe enough, they could enter the drug development pipeline and, one day, become a standardized treatment, with a well-understood pharmacological profile, in much the same way that the discover of salicylic acid in willow bark led to the development of aspirin (acetylsalicylic acid). But we need strong, reproducible positive results first.

Does this mean we should stop drinking chamomile tea? Absolutely not. If you enjoy the taste (and aren’t allergic to it, as some people are), drink away. But we shouldn’t let historical and anecdotal evidence trump scientific data. Next time you want to pull yourself closer to sleep, boil the water but withhold the tea bag. See how you feel. You might be surprised at the power of age-old rituals.

 

@crackedscience

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