This post will try to cover all the most prominent studies and research to date on the health benefits of kiwifruit .
On the internet you will find many approximations and outright wrong statements, so I’ll try to always cite the medical sources (pointing out any possible bias) with links to the studies on pubmed, so you know what you’reading
is actually science and not some fluff a random blogger made up to sell you the latest supplements.
Kiwifruit for Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome is currently affecting from 10 to 20% of the population, and the first line treatment commonly prescribed was a drug called tegaserod , that was recently pulled from the
drug market for having adverse effects on health (it increased the risk stroke and heart attacks).
A very effective alternative has been found by a group of scientists (source: PMID:
21147704, “Kiwifruit improves bowel function in patients with irritable bowel syndrome with constipation“), and it consists of eating two Hayward green kiwifruits per day for 4 weeks.
Scientists concluded that “kiwifruit consumption for 4 weeks shortens colon transit time, increases defecation frequency, and improves bowel function in adults diagnosed with IBS/C”, making it a great alternative to drugs with a proven track record.
A second study (which you can find here) also agrees with the findings of the previous one, so the verdict is out: kiwifruit helps you reduce the symptoms of irritable bowel syndrome in a safe way, with just two kiwis a day.
Antioxidants in Kiwifruit and DNA repair
You’ll often hear about the purported effects of antioxidants that “help prevent cancer” from a variety of sources. This refers to a landmark study in 2003 (which you can find here Nutritional modulation of DNA repair in a human intervention study), that effectively proved that the presence of certain plant foods in our diet tends to reduce cancer rates by protecting our DNA from being damaged.
This mechanism, though, is just our first line of defense: our cells have a second one that consists of actually repairing DNA damage that has already occurred.
In comes the International Kiwifruit Organization, that funded a study in 2010 on more than 100 subjects, comparing the rates of DNA repair damage of people eating from zero to three kiwifruits a day. The results are pretty clear: people eating kiwifruits daily show higher levels of DNA repair, directly reducing DNA mutations (the primary mechanism with which a normal cell becomes cancerous). An interesting fact about this study is that it doesn’t appear to be more beneficial to eat three kiwifruits a day compared to one..you either eat kiwi or you dont, so it seems to work in an on/off fashion that warrants further investigation.
Kiwifruit for Insomnia
Almost one third of the adult population currently suffers from sleeping problems, and even pharmacological aids have proven not completely effective, due to side-effects, low rates of efficacy, or daytime drowsiness.
Another study funded by a kiwifruit company (which I mention for the sake of honesty, but which seems to be well executed) recently proved that consumption of two kiwifruits, one hour before bedtime significantly improves objective markers of sleep quality, “including time to bed, time of sleep onset, waking time after sleep onset, time of getting up, total sleep time, and self-reported sleep quality and sleep onset latency, waking time after sleep onset, total sleep time, and sleep efficiency before and after the intervention”.
The study concludes that “Total sleep time and sleep efficiency were significantly increased (13.4% and 5.41%, respectively). Kiwifruit consumption may improve sleep onset, duration, and efficiency in adults with self-reported sleep disturbances.”.
General Health Effects of Kiwi
Kiwifruit, being a fruit with fiber, several vitamins and minerals, is a healthy choice in general, providing for a good source of carbohydrates that get digested slowly (thanks to the presence of fiber), and having very low levels of fat and protein.
They are mostly prized for the exceptional content of some vitamins, cited in a study from the Journal of Pharmacology in 2013, which reports that “Compared with other commonly consumed fruit, both green and gold kiwifruit are exceptionally high in vitamins C, E, K, folate, carotenoids, potassium, fibre, and phytochemicals acting in synergy to achieve multiple health benefits”