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Kiwifruit for Insomnia

Two kiwi fruit an hour before bedtime may improve sleep quality and duration without the side effects associated with sleeping pills.

July 19, 2013 |
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Supplementary Info

Sources Cited

Lin Xu, Chao Qiang Jiang. Short or Long Sleep Duration Is Associated with Memory Impairment in Older Chinese: the Guangzhou Biobank Cohort Study. Sleep 2011 34(5):575-580.

M. M. Ohayon. Epidemiology of insomnia: What we know and what we still need to learn. Sleep Med Rev 2002 6(2):97-111.

S. R. Patel, A. Malhotra, X. Gao, F. B. Hu, M. I. Neuman, W. W. Fawzi. A prospective study of sleep duration and pneumonia risk in women. Sleep 2012 35(1):97-101.

F. P. Cappuccio, L. D'Elia, P. Strazzullo, M. A. Miller. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010 33(5):585-592.

M. A. Grandner, L. Hale, M. Moore, N. P. Patel. Mortality associated with short sleep duration: The evidence, the possible mechanisms, and the future. Sleep Med Rev. 2010 14(3):191-203.

H. H. Lin, P. S. Tsai, S. C. Fang, J. F. Liu. Effect of kiwifruit consumption on sleep quality in adults with sleep problems. Asia Pac J Clin Nutr. 2011 20(2):169-174.

M. Basner. Sleep duration and chronic sleep debt: are 6 hours enough? Biol Psychol. 2011 87(1):15-16.

H. P. Van Dongen, G. Maislin, J. M. Mullington, D. F. Dinges. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep. 2003 26(2):117-126.

S. Ikehara, H. Iso, C. Date, S. Kikuchi, Y. Watanabe, Y. Wada, Y. Inaba, A. Tamakoshi, JACC Study Group. Association of sleep duration with mortality from cardiovascular disease and other causes for Japanese men and women: the JACC study. Sleep. 2009 32(3):295-301.


Images thanks to Simo ubuntu and Lisa Rosario Photography via Flickr and Batholith via Wikimedia Commons. Thanks to Stephane Lahaye and Ellen Reid for their keynote help.


The number one question in sleep research is why do we sleep, followed by the question “How much sleep do we need?” After literally hundreds of studies we still don't know the best answer to either question. A few years ago I featured a large hundred thousand-person study suggesting that "Both short and long sleep duration were associated with increased mortality, with people getting around 7 hours of sleep living longest. Since then a meta-analysis of all such studies including more than a million people was published, and they found the same thing. We still don't know, though, if sleep duration is a cause, or simply a marker of, ill health. Maybe sleeping too little or too long does make you unhealthy, or maybe we see the associated shortened lifespan because being unhealthy causes you to sleep shorter or longer.

Similar work has now been published on cognitive function. After controlling for long list of factors, men and women in their 50s and 60s getting 7 or 8 hours appeared to have the best short-term memory, compared to those that got much more or much less. Same thing was just demonstrated with immune function: "both reduced and prolonged habitual sleep durations were associated with an increased risk of pneumonia.”

It's easy to not get too much sleep, set an alarm. But what if you're having problems getting enough? What if you're the 1 in 3 adults that suffers symptoms of insomnia? Sure there are drugs like valium you can take for insomnia in the short term, but they have a number of adverse side effects. Non-pharmacological approaches such as cognitive behavioral therapy are often difficult, time-consuming, and don't always work. Wouldn't it be great to have "natural treatments that can improve both sleep onset and help patients improve the quality of sleep while improving next-day symptoms over the long term?

The "Effect of kiwifruit consumption on sleep quality in adults with sleep problems." Two kiwi fruit an hour before bed every night for four weeks. Why study kiwifruits? Well, people with sleep disorders tend to have high levels of oxidative stress so maybe antioxidant rich foods may help, but all fruits and vegetables have antioxidants. Well kiwifruits contain twice the serotonin of tomatoes, but it shouldn't cross the blood/brain barrier. Kiwifruit has folate, and a deficiency might cause insomnia, but there's a lot more folate in some other plant foods. The reason they studied kiwifruits is because they got grant money from a kiwifruit company, and I'm glad they did because they found some really remarkable results: Significantly improved sleep onset, duration, and efficiency using both subjective and objective measurements. Went from sleeping 6 hours a night to 7, just eating a few kiwifruit.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

More on the power of kiwis in my videos Kiwifruit and DNA Repair and Kiwifruit for Irritable Bowel Syndrome, and more on sleep in Sleep & Immunity and Optimal Sleep Duration.

Videos on other natural remedies for various conditions include:

Stay tuned for Monday's video of the day Tart Cherries for Insomnia.

For more context, check out my associated blog post: Two Kiwifruit an Hour Before Bedtime and Foods with Natural Melatonin.

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Guest
    • Michael Greger M.D.

      You have to put a excessive cuteness *warning* on that link! :)

  • BPCveg

    If they received “grant money from a kiwifruit company”, then why is their study any less biased than those studies you previously referred to that were funded by the salt or dairy or meat companies. Isn’t the whole purpose of science to reach objective explanations by eliminating biases? If so, shouldn’t we disregard all studies that are funded by corporations?

    • mama

      All studies are funded by someone.

      • BPCveg

        True, but some people are bad.

    • Michael Greger M.D.

      Just like we should take studies funded by the Salt Institute with a grain of salt, we should take these findings with a grain of kiwi :)

      The difference between this and the other examples you cite is what’s the worst that can happen? Even if this data was totally fraudulent, the worst case scenario if someone follows this advice is that they eat a really healthy fruit and only get all its other benefits (even if it doesn’t actually help with sleep). That’s the wonderful thing about plant-based research!

      And industry influence is rarely about outright fraud but about study design. One just has to be mindful about study sponsors to make sure the study wasn’t constructed in a way to bias the results.

      • Thea

        re: “One just has to be mindful about study sponsors to make sure the study
        wasn’t constructed in a way to bias the results. That is something for
        which I am indeed constantly on the lookout.”

        That’s what the average lay person (and according to Dr. Campbell, even the average scientist and medical professional) can’t do for themselves / must rely on a responsible expert for. That you care about this aspect of studies is one of the reasons I love your work.

        Thanks for taking the time to answer BPCveg’s question as I think it was a good one. And you had a good answer too.

      • HemoDynamic, M.D.

        Well put Dr. Greger!

        In reference to “industry influence is rarely about outright fraud. . .” I don’t know if you (or anyone reading this) has ever seen this documentary on the business of cancer but it will open anyone’s eyes to the corruption of the FDA, NCI (National Cancer Institute), ACS (American Cancer Society) and AMA (American Medical Association) and expose the outright fraud involved in Cancer treatment and the bias to ensure expensive, pharmaceutically based therapy and procedures.
        Backed up from numerous hard statistics, peer reviewed articles, research and verifiable references.

        Warning not a feel-good movie and will utterly disappoint one about the absolute corruption involved in the treatment (or lack thereof) of cancer.

        Titled, “Healing Cancer from the Inside Out.” A link for Amazon is below if you are further interested.

      • BPCveg

        Thanks for your reply, though I have to disagree with you.
        You yourself have provided evidence that certain plant products (e.g. coconuts and avocados) are of dubious health value – but you had to cut through a lot of conflicting studies to reach those conclusions. So how come you are so accepting of corporate sponsored kiwi research? Is it any more obvious that a kiwi is beneficial than a coconut? Same question applies for any animal product!

        I hope you were joking when you said that “industry influence is rarely about outright fraud but about nuanced study design”. Else it may be time to re-read ‘How to Lie with Statistics’ by Darrel Huff.

        Corporations have no other interest than profit. They will bend-over-backward to skew research in their own favour.

        I second the motion made by SFV below, which suggests that some kind of validity rating be provided to give your audience a sense of the credibility of any study that you report.

      • Lloyd

        Great points Dr. Greger.

  • rumicat

    Interesting, but I’m wondering if it’s just the combination of sugar and fiber in the kiwifruit that are doing the trick. Low blood sugar levels can raise your cortisol levels and keep you up at night, one of the reasons a little milk before bed has been recommended for years. Would a glass of soymilk do the same thing? Maybe the Silk people should fund a study.

  • Paddycakes

    What about eating Kiwi fruit for diabetics?!

  • ekon

    Interesting for myself. But my mother 70 years old is suffering from insomnia. Unfortunately she has some kiwifruit allergy. Any suggestions? Thanks in advance.

  • HemoDynamic, M.D.

    Let me sleep on that!
    ;-0 zzzzzz

  • BarbaraH

    Did that study have a control group or a placebo group? I can’t tell from the abstract, but it looked like it didn’t. Did the subjects know they were in a study designed to see if sleep could be improved eating kiwi?

    I’d like to see the results of a study which subjects think is looking at whether kiwi impairs sleep. Probably they’d be up all night.

    Did anyone else look at that time-lapse video of the baby and notice how underweight, colicky and covered with eczema he was for the first few months? I wonder if he had an undiagnosed dairy allergy. Poor thing. He did not look like a happy baby for quite a long time.

  • SFV

    Hi Dr. Greger. I think it would be a big improvement if the videos could briefly indicate the limitations of the studies that are mentioned. There is basically no meaningful conclusion from a study with 24 subjects and no control group. Few people, if any, will be able to act on every study that you mention, so distinguishing well-designed studies and highly substantiated results and recommendations from methodologically weak studies and tentative conclusions would help viewers to focus on the most critical actions they can take to enhance their health. I know that’s what you are aiming for in your longer video summaries. I also understand that time is very limited on the daily video clips. Maybe you could have a 1-to-5 type validity rating for the studies that you cite. Viewers without a research background or a strong grounding in nutrition issues might come away thinking the the China Study and the kiwi study are equally valid. That would be a shame. I don’t want to end this comment without expressing my daily gratitude for the work that you are doing for the benefit of us all.

    • CharlieB.

      I strongly support this suggestion.

    • superfatass

      Can simply try 2 kiwis an hour before bedtime and see if it works for you! Like with anything else, one’s man food is another man’s bad meal.

      • tanonymus

        Guess he does not ask for himself but “for the greater good”.

  • Mike Quinoa

    Just remember, if you ate some watermelon earlier with your dinner (for your erectile dysfuntion), not to have kiwifruit for a bedtime snack—cross-purposes.

  • Lloyd

    I’m the worst sleeper I know ever since childhood. Thanks very much for the research.

  • perlis

    Too bad the starting image is of a baby sleeping on its stomach. This is not the recommended position nowadays — to avoid infant sudden death syndrome.

    • Michael Greger M.D.

      yes–face up to wake up! I’ve got three videos on SIDS.

  • Eileen

    Would you please look into and report on perilla seeds?
    It seems they are now being hailed as the next big “superfood” with the “selling factor” being their Omega 3 to Omega 6 ratio (allegedly 6:1).
    Is there any truth to the claims or is this more hype?

  • PamyCST

    Love the subtitles, but could they have a background so they’re easier to read? Not that I actually READ them… but I’m thinking of others…

  • superfatass

    Thanks! Will try this instead of my regular 2 shots of Jack Daniels.