Two kiwis a day for constipation: what the EU approved and what the trials show
The EU approved a bowel-function claim for green kiwifruit in 2025. Two trials back it, one funded by a kiwi marketer. What they found and how to try it.
Short answer
Two green kiwis a day may help mild constipation. In 2025 the EU authorized the claim that green kiwifruit contributes to normal bowel function by increasing stool frequency, at 200 g of flesh a day, which takes about three medium kiwis, since two weigh around 140 g. Two four-week trials found improvements, but one was sponsored by the kiwi marketer Zespri and had two authors on its payroll, and the other was small and only partly randomized. Treat kiwi as a reasonable food-first option, not a proven treatment, and see a doctor if constipation is new or severe.
Key takeaways
- The EU claim, adopted on July 30, 2025, says green kiwifruit contributes to normal bowel function by increasing stool frequency. It requires 200 g of flesh a day.
- The larger trial (184 adults, four weeks) was sponsored by Zespri, and two of its authors are Zespri employees. It showed about 1.5 more complete bowel movements a week in constipated people.
- The smaller US trial (79 adults, partly randomized) found kiwi, prunes and psyllium all helped, with similar response rates. Kiwi had the fewest side effects.
- 200 g of green kiwi flesh has about 6 g of fiber by USDA values. Gold kiwi has less than half as much per 100 g.
- Neither trial shows that kiwi works better than other options for everyone.
On July 30, 2025 the European Commission adopted a rule allowing food makers to say: “Consumption of green kiwifruit contributes to normal bowel function by increasing stool frequency.” The condition is a daily intake of 200 g of fresh green kiwi flesh.1 That is a sentence you can put on a pack, which is different from proof that it works for you. Here is what stands behind it.
What the EU did and did not approve
The Commission acted on a scientific opinion the European Food Safety Authority published on June 11, 2021. EFSA concluded that a cause-and-effect relationship had been established between eating green kiwifruit and maintenance of normal defecation, and the target population is the general population.1 A health claim for a food is not a medicine claim. It says the food supports a normal function, not that it treats constipation.
The trials
| Gearry et al. 2023 | Chey et al. 2021 | |
|---|---|---|
| Participants | 184 adults: 63 healthy, 60 with functional constipation, 61 with IBS-C | 79 adults with chronic constipation, 75 with complete data |
| Design | Crossover, three countries, 4 weeks each of kiwi and psyllium (7.5 g/day) | “Partially randomized”, exploratory, 4 weeks of kiwi, prunes (100 g) or psyllium (12 g) |
| Main result | Kiwi: +1.53 complete spontaneous bowel movements a week in functional constipation and +1.73 in IBS-C | All three increased weekly bowel movements; response rates were similar |
| Notable | No weekly difference between kiwi and psyllium in bowel movements. Averaged over treatment, kiwi’s effect was larger in the combined constipated group (P = 0.038), and kiwi scored better on the symptom-scale constipation items (P = 0.026 and 0.024) | Kiwi had the fewest side effects, the lowest dissatisfaction and improved bloating scores |
| Caveat | Sponsored by Zespri. Participants could not be blinded | Small. Not fully randomized |
The first trial found that two kiwis a day were associated with a clinically relevant increase of 1.5 or more complete bowel movements a week in people with functional constipation and with IBS-C, and with better scores on a validated gastrointestinal symptom scale. No significant adverse events were reported. Psyllium did not reach significance in people with functional constipation but did in the IBS-C group.3
The second trial was small, and the authors called it exploratory. For its main outcome, the share of people with at least one extra complete bowel movement a week, the three treatments were statistically similar.4 That makes it a useful reminder that kiwi is one option among several, not a winner.
Who paid
Zespri International, a kiwifruit marketer, was the principal sponsor of the larger trial and “reviewed, approved, and funded the study design”. Two of the authors are employed by Zespri, two others sit on its Science Advisory Board and have received grants, and others have received research travel grants. The paper states that the funder did not contribute to the study design or data analysis, and study staff who analyzed data were blinded.3 None of that makes the findings wrong. It is the reason we call the evidence encouraging, not conclusive.
Why kiwi might work
The trial authors point to the fiber in the fruit’s cell walls, which has a large swelling and water-holding capacity in a test tube and may soften stool. They also suggest other components, such as raphides, may alter mucin production, and cite an MRI study showing more water in the small bowel and ascending colon after two kiwis.3 The amount of fiber alone is modest: 200 g of green kiwi flesh has about 6 g by USDA values, at 3.0 g per 100 g.5
How to try it
- Eat two green kiwis a day, peeled, as in the trials. Check that it adds up to about 200 g of flesh.
- Keep it up for four weeks, the length of both trials, before judging.
- Change little else so you can tell what helped.
- Stop and see a doctor if there is no change or things get worse.
See a doctor if
Constipation is new and lasts, you notice blood in your stool, you are losing weight without trying, or you have severe pain or vomiting. Kiwi is a food, not treatment for an underlying condition.
Frequently asked questions
How many kiwis should I eat for constipation?
Both trials used two green kiwis a day for four weeks. The EU claim requires 200 g of flesh. In the larger trial, two kiwis supplied about 6 g of fiber, which fits 200 g at USDA’s 3.0 g per 100 g. A medium kiwi is 69 g by USDA’s portion size, so two medium ones are only about 140 g (4 g of fiber) and it takes three to reach 200 g. Judge the effect after two to four weeks of daily eating.
Do I eat the skin?
The trial participants were instructed to eat the kiwi without the skin, so the evidence is for peeled fruit. No trial data covers eating the skin.
Do gold kiwis work too?
The EU claim and the trials are about green kiwifruit. USDA lists 3.0 g of fiber per 100 g for green kiwi and 1.4 g for SunGold, and the trials did not test gold.
Is kiwi better than prunes or psyllium?
The evidence does not say that. In the US trial, response rates were similar across kiwi, prunes and psyllium. In the larger trial, both raised weekly complete bowel movements and no single week differed significantly between them. Averaged over the whole treatment in the combined constipated group, kiwi had the larger effect on that count (P = 0.038), and it scored better on the constipation items of the symptom scale (P = 0.026 in functional constipation, P = 0.024 combined). That trial was sponsored by the kiwi marketer and nobody could be blinded to which food they were eating.
Sources
Figures, study results and official recommendations in this article come from these sources. Everyday cooking and shopping tips are our own judgment.
- Commission Implementing Regulation (EU) 2025/1560 authorising a health claim for green kiwifruit and normal bowel function. Official Journal of the European Union, July 31, 2025. eur-lex.europa.eu
- EFSA Panel on Nutrition, Novel Foods and Food Allergens. Green kiwifruit (Actinidia deliciosa var. Hayward) and maintenance of normal defecation. EFSA Journal. 2021;19(6):6641 (as cited in recital 8 of Regulation 2025/1560). doi.org
- Gearry R, et al. Consumption of 2 green kiwifruits daily improves constipation and abdominal comfort: results of an international multicenter randomized controlled trial. American Journal of Gastroenterology. 2023;118(6):1058-1068. doi.org
- Chey SW, Chey WD, Jackson K, Eswaran S. Exploratory comparative effectiveness trial of green kiwifruit, psyllium, or prunes in US patients with chronic constipation. American Journal of Gastroenterology. 2021;116(6):1304-1312. doi.org
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy: kiwifruit, green, raw (FDC ID 168153: 3.0 g fiber per 100 g); kiwifruit, ZESPRI SunGold, raw (168211: 1.4 g). fdc.nal.usda.gov
This article is general information, not medical advice. If you have ongoing digestive symptoms, a diagnosed condition like IBS or IBD, or you are pregnant, talk to a doctor or registered dietitian before changing your diet.
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