Kiwi for Constipation: What the Studies Show
Kiwifruit has become one of the best studied foods for constipation. Small trials suggest two a day may help you go more often, with few side effects. Here is what was found, and its limits.
Most constipation advice sounds the same: more fiber, more fluids, more movement. It is good advice, but it can be hard to know which foods are worth adding. In recent years one ordinary fruit has had more attention than most: the green kiwi.
Recent trials, run in countries as far apart as the United States, Italy, Japan and New Zealand, have tested kiwis against standard fiber treatments. The results are encouraging, but the studies are small. Here is what they found, how to try it sensibly, and when constipation needs a doctor rather than fruit.
Why kiwi might help
Kiwi is a good source of fiber, with about 3 g in a half-cup serving, according to Harvard Health. Eating more fiber, built up gradually, is one of the first things the NHS suggests for constipation.
Harvard Health also mentions raphides, tiny needle-shaped crystals in the fruit, as one possible reason kiwi seems to help bowel function. Along with the fiber, these are thought to help, but the exact reasons are still being studied.
Two-Kiwi Morning Bowl
You need
- ripe green kiwis2
- rolled oats40 g (1/2 cup)
- milk, plant drink or water150 ml (2/3 cup)
- plain yogurt, optional2 tbsp
- ground linseed (flaxseed), optional1 tsp
- large glass of water to drink alongside1
Method
- Put the oats and milk or water in a small pan. Simmer, stirring, for 3 to 5 minutes until creamy. You can also soak them overnight in the fridge instead.
- Peel the kiwis, as in the 2023 trial, and slice them.
- Spoon the oats into a bowl, add the yogurt if using, and top with the kiwi slices.
- Sprinkle over the linseed and eat with a full glass of water.
Tips
- Ripe kiwis give slightly when pressed. Firm ones ripen in a few days at room temperature, faster in a bag with an apple.
- Not a porridge person? Simply cut two kiwis in half and scoop them out with a spoon.
- If you are new to high-fiber breakfasts, start with one kiwi and the oats, and build up over a week or two. The NHS advises increasing fiber gradually.
What the evidence says
A US trial published in the American Journal of Gastroenterology compared green kiwifruit, prunes and psyllium, a common fiber supplement, in about 80 adults with chronic constipation over four weeks. All three increased bowel movements. Kiwi seemed to do this with fewer side effects. Harvard Health points out the limits: the study was small, participants knew what they were taking, most were women, and nobody knows yet whether the benefit lasts beyond four weeks.
A larger international trial, reported in the same journal in 2023, included more than 180 adults in Italy, Japan and New Zealand. Participants ate two peeled green kiwis a day for four weeks, and in another period took 7.5 g of psyllium a day. Both helped people with constipation have more bowel movements, with less straining and tummy pain. Kiwi was slightly more effective than psyllium.
So the honest summary is this: kiwi looks like a reasonable, gentle food to try, and in these trials it held its own against psyllium and prunes. But the evidence comes from a few short, fairly small studies, and kiwi is not a treatment for ongoing bowel problems.
The habits that still matter most
The NHS suggests increasing fiber gradually, drinking plenty of water and other fluids, avoiding alcohol and staying active, for example with a daily walk. It also lists fruits containing sorbitol, such as apples, apricots, grapes, raisins, raspberries and strawberries, so kiwi can be one fruit among several.
Routine helps too. The NHS advises keeping a regular time and place for the toilet, not ignoring the urge to go, and trying a low stool under your feet. Changes can take a few days or a few weeks to make a difference, so give any new habit time.
Questions people ask
How many kiwis a day for constipation?
The trials mostly used two green kiwis a day for four weeks. That is a sensible amount to try, but start with one if you are not used to much fiber.
Do I need to peel the kiwi?
The 2023 trial used peeled green kiwis, so peeling is fine. Some people also eat the washed skin, but the trials do not tell us whether that adds any benefit.
Is kiwi better than prunes?
In one small US trial, kiwi, prunes and psyllium all increased bowel movements, and kiwi seemed to cause fewer side effects. That is not strong enough to call one clearly better, so choose the one you enjoy.
Sources
- Constipation — NHS
- Another natural remedy for constipation? — Harvard Health Publishing
- Try this natural remedy to stay regular — Harvard Health Publishing
- Latex Allergy — Cleveland Clinic
This article is for general information only and is not medical advice. Herbs can interact with medicines and health conditions. Talk to a doctor or pharmacist before trying a herbal remedy, especially if you are pregnant, breastfeeding, giving it to a child, or taking any medication.
