Quick Answer: One medium green kiwi (about 69 g of flesh) contains roughly 42 calories, 2.1 g of fibre, 64 mg of vitamin C and 28 mcg of vitamin K.
That single fruit covers about 71 percent of the Daily Value for vitamin C, which is the strongest thing about kiwi by a distance. The benefit with the best clinical evidence behind it is relief of constipation: randomised trials show two green kiwifruit a day works about as well as fibre-matched psyllium, with less bloating and cramping. Most of the other claims made for kiwi, including the widely repeated idea that it can replace aspirin, are not supported.
Important: Kiwi Is Not a Substitute for Prescribed Aspirin
This needs to come before anything else, because the opposite advice circulates widely and it is dangerous.
A small study has reported that kiwifruit consumption reduced platelet aggregation in healthy volunteers. That is a real finding, and it is a long way from a clinical outcome. It does not make kiwi a replacement for low-dose aspirin, and nobody should stop prescribed antiplatelet medication in favour of eating fruit.
Aspirin is usually prescribed for secondary prevention, meaning after a heart attack, a stroke, or a stent. Stopping it without medical advice raises the risk of exactly the event it was prescribed to prevent. If you are on aspirin, clopidogrel, warfarin or a DOAC and want to change anything, that is a conversation with the doctor who prescribed it.
There is a genuine interaction worth knowing in the other direction: kiwi contains a meaningful amount of vitamin K, about 34 percent of the Daily Value per 100 g, which affects how warfarin works. The advice there is consistency rather than avoidance, and it is worth mentioning to your anticoagulation clinic.
Kiwi Fruit Nutrition Facts
Green kiwifruit, raw, from USDA FoodData Central and rounded.
| Nutrient | Per 100 g | %DV | 1 medium kiwi (~69 g) |
|---|---|---|---|
| Calories | 61 | – | 42 |
| Vitamin C | 92.7 mg | 103% | 64 mg |
| Vitamin K | 40.3 mcg | 34% | 27.8 mcg |
| Copper | 0.13 mg | 14% | 0.09 mg |
| Dietary fibre | 3.0 g | 11% | 2.1 g |
| Vitamin E | 1.46 mg | 10% | 1.0 mg |
| Potassium | 312 mg | 7% | 215 mg |
| Folate | 25 mcg | 6% | 17 mcg |
| Magnesium | 17 mg | 4% | 12 mg |
| Calcium | 34 mg | 3% | 23 mg |
| Iron | 0.31 mg | 2% | 0.21 mg |
| Total carbohydrate | 14.7 g | 5% | 10.1 g |
| Sugars (natural) | ~9 g | – | ~6 g |
| Protein | 1.14 g | 2% | 0.8 g |
| Total fat | 0.52 g | 1% | 0.36 g |
| Sodium | 3 mg | 0% | 2 mg |
| Lutein + zeaxanthin | 122 mcg | – | 84 mcg |
Three things stand out, and two of them correct claims that circulate about this fruit.
- Vitamin C is the headline and it is exceptional. Gram for gram, kiwi carries roughly three times the vitamin C of an orange. One fruit gets most adults to their daily requirement.
- Kiwi is not a magnesium source. It supplies about 17 mg per 100 g, roughly 4 percent of the Daily Value. Figures around 71 mg are simply wrong.
- Kiwi is not low in sugar. At around 9 g per 100 g it sits in the normal range for fruit. It has a low-to-moderate glycaemic index and fits most eating patterns comfortably, but describing it as very low in sugar is inaccurate, and anyone managing diabetes should count it as they would any fruit.
The Benefit With Real Evidence: Constipation
Most “superfruit” claims collapse under scrutiny. This one does not, and it is the reason kiwi is worth writing about at all.
- An international multicentre randomised controlled trial published in the American Journal of Gastroenterology gave 184 participants healthy controls, people with functional constipation, and people with constipation-predominant IBS either two green kiwifruit or 7.5 g of psyllium daily for four weeks, then crossed them over. The functional constipation group gained an average of 1.53 additional complete spontaneous bowel movements per week on kiwifruit, and reported improved abdominal comfort.
- A US trial from the University of Michigan compared two green kiwifruit a day against prunes and psyllium in patients with chronic constipation. All three improved bowel movements; kiwifruit produced less pain, cramping and bloating than the alternatives.
- A separate randomised trial found two gold kiwifruit daily as effective as fibre-matched psyllium, and significantly reduced straining.
Two green kiwifruit deliver roughly 6 g of fibre, which is comparable to the psyllium dose they were tested against. The proposed mechanisms are that fibre plus the fruit’s water-holding capacity increase stool bulk and softness, while the enzyme actinidin appears to speed gastric emptying.
The disclosure that belongs alongside this: most of these trials were funded in whole or part by Zespri International, the world’s largest kiwifruit marketer, and several authors have financial relationships with the company. That does not invalidate the findings – they are randomised, controlled and published in reputable journals but it is the kind of thing a reader deserves to be told, and almost no article about kiwi mentions it.
The video below, from a registered dietitian at Mayo Clinic, covers the broader dietary and behavioural approach to constipation that kiwi fits into.
If constipation is persistent, or comes with bleeding, unexplained weight loss or a change in bowel habit that lasts, that needs a doctor rather than a dietary fix.
What Else Kiwi Genuinely Offers
- Vitamin C for normal immune function. Vitamin C is required for immune cells to work properly, and kiwi is an excellent source. What that does not mean is that eating kiwi prevents colds or flu. Adequate intake supports normal function; exceeding it does not add protection.
- Vitamin K. 34 percent of the Daily Value per 100 g, needed for blood clotting and involved in bone metabolism. A genuinely strong figure for a fruit.
- Actinidin, a protein-digesting enzyme. Unique among common fruits and the reason kiwi tenderises meat and can help break down protein in a meal. Note that this is actinidin, not bromelain – bromelain is the enzyme in pineapple, and kiwi does not contain it.
- Lutein and zeaxanthin. Present at 122 mcg per 100 g. These accumulate in the retina and are associated with eye health in observational research. They are not provitamin A carotenoids, so they do not convert to vitamin A in the body, and kiwi is not a vitamin A source.
- Low energy density and high water content, which makes kiwi a filling low-calorie choice, in the same way any whole fruit is.
Claims That Do Not Hold Up
Kiwi attracts an unusual volume of overstatement. For clarity:
| Claim | Where it stands |
|---|---|
| Detoxifies the body and flushes out toxins | Not supported. The liver and kidneys clear metabolic waste continuously. No food improves on that, and “detox” is a marketing concept rather than a physiological one. |
| Protects against cancer | Not supported. Diets rich in fruit and vegetables are associated with lower risk of some cancers, but no single fruit prevents cancer or removes the risk of it. |
| Keeps asthma under control | Not supported as a treatment. Asthma is managed with prescribed inhalers and a plan from a clinician. Diet is not a substitute. |
| Dissolves kidney stones | Not supported, and possibly backwards. Kiwi contains oxalate, so anyone who forms calcium oxalate stones should discuss intake with their clinician rather than increase it. |
| Repairs damaged DNA | Overstated. Antioxidant activity measured in a laboratory is not the same as repairing DNA in a person. |
| Prevents depression | Not supported. |
| Protects against liver damage | Not supported. |
| Reduces hair fall and strengthens bones | Not supported. |
| Cures insomnia | Very weak. One small, non-randomised study is often cited. It is not adequate evidence for a sleep claim. |
| Boosts vitamin A production via lutein and zeaxanthin | Incorrect. Neither converts to vitamin A. |
Kiwi Allergy: The Side Effect That Actually Matters
Older versions of this article said kiwi “rarely has any side effects” and then described anaphylaxis and pancreatitis in the same breath. That minimisation is worth reversing, because kiwi allergy is genuinely significant.
- Kiwi is a recognised food allergen and reactions range from mild oral symptoms to anaphylaxis, which is a medical emergency requiring adrenaline and emergency care.
- Oral allergy syndrome is the commonest presentation: itching or tingling of the lips, mouth and throat shortly after eating, often in people already sensitised to birch pollen.
- Latex-fruit syndrome. People with latex allergy have a higher likelihood of reacting to kiwi, along with banana, avocado and chestnut, because of shared proteins. If you have a latex allergy, raise kiwi with your allergist.
- Children can react more severely than adults, and reactions have occurred on first known exposure.
- The enzyme causes harmless effects too. Actinidin can produce a mild burning or tingling on the tongue in people who are not allergic, particularly with very ripe fruit. That is not the same as an allergic reaction, but if you are unsure, get it assessed rather than guess.
Other practical points: kiwi’s oxalate content matters for calcium oxalate stone formers, and its vitamin K matters for anyone on warfarin, as covered above.
How to Eat It
- Two a day is the studied amount for constipation. There is no reason to treat that as a maximum for general eating, and no evidence that a particular time of day matters.
- The skin is edible and adds fibre. Rub off the fuzz, wash it, and eat it like a plum if the texture suits you. Gold kiwi has thinner, smoother skin and is easier to eat whole.
- Green or gold is mostly preference. Gold is sweeter and higher in vitamin C; green is tarter and much higher in actinidin, which is likely why green dominates the constipation research.
- Actinidin prevents gelatine setting. Fresh kiwi will stop a jelly or panna cotta from firming and will turn dairy bitter if left to sit. Cook the fruit briefly first, or use tinned.
- Ripen at room temperature, ideally in a paper bag with a banana, then refrigerate once it yields to gentle pressure.
Frequently Asked Questions
About 64 mg in one medium green kiwi of roughly 69 g, which is around 71 percent of the Daily Value. Per 100 g green kiwifruit supplies 92.7 mg, or 103 percent of the Daily Value, which is roughly three times the vitamin C of an orange gram for gram. Gold kiwifruit carries even more. Vitamin C is comfortably the strongest nutritional feature of this fruit.
Yes, and this is the best-evidenced benefit. An international multicentre randomised trial found people with functional constipation gained an average of 1.53 extra complete spontaneous bowel movements per week on two green kiwifruit daily, comparable to fibre-matched psyllium and with better abdominal comfort. A US trial comparing kiwifruit, prunes and psyllium found all three helped, with kiwifruit causing less pain, cramping and bloating. Two green kiwifruit supply roughly 6 g of fibre. Note that much of this research was funded by Zespri, a kiwifruit marketer.
No, and this claim is dangerous. A small study reported reduced platelet aggregation in healthy volunteers after eating kiwifruit, which is a long way from a clinical outcome. Low-dose aspirin is usually prescribed after a heart attack, stroke or stent, and stopping it without medical advice raises the risk of the event it was prescribed to prevent. Never substitute food for prescribed antiplatelet or anticoagulant medication. Kiwi’s vitamin K content is also relevant if you take warfarin, so mention it to your anticoagulation clinic.
The one that matters is allergy. Kiwi is a recognised food allergen and reactions range from oral allergy syndrome, meaning itching or tingling of the lips, mouth and throat, through to anaphylaxis, which is a medical emergency. People with latex allergy are more likely to react, through latex-fruit syndrome, which also involves banana, avocado and chestnut. Children can react more severely than adults. Separately, the enzyme actinidin can cause a harmless mild tingling in people who are not allergic. Kiwi also contains oxalate, relevant to calcium oxalate stone formers, and vitamin K, relevant on warfarin.
Kiwi contains about 9 g of sugar per 100 g, which is a normal amount for fruit rather than a low one. It has a low-to-moderate glycaemic index and roughly 3 g of fibre per 100 g, so it fits most eating patterns comfortably, but describing it as very low in sugar is inaccurate. If you are managing diabetes, count kiwi as you would any fruit and follow your dietitian’s guidance on portions.
No. Bromelain is the protein-digesting enzyme found in pineapple. Kiwi contains a different enzyme called actinidin, which does a similar job and is the reason kiwi tenderises meat and stops gelatine from setting. Green kiwifruit contains roughly eight times more actinidin than gold. Articles attributing bromelain to kiwi have confused the two fruits.
Yes. The skin is edible and adds fibre. Rub off the fuzz under running water and eat the fruit like a plum. Gold kiwifruit has thinner, smoother skin and is easier to eat whole than green. Some people find the texture unpleasant, which is a preference rather than a safety issue.
Two a day is the amount used in the constipation trials, and it is a sensible general figure. There is no established maximum for healthy people and no evidence that eating kiwi at a particular time of day changes anything. One fruit already covers most of an adult’s daily vitamin C. If you take warfarin, form calcium oxalate kidney stones, or have a latex or food allergy, discuss intake with your clinician.
Mostly preference. Gold kiwifruit is sweeter, has thinner skin and carries more vitamin C. Green is tarter and contains roughly eight times more of the enzyme actinidin, which is probably why green dominates the constipation research, though trials have shown gold kiwifruit works too. Nutritionally they are close, and either is a good choice.
Related Reading
- How to read nutrition labels to make smarter food choices
- Asparagus nutrition facts, including the warfarin and vitamin K point
- Almond nutrition facts and what the evidence shows
- How to spot a fad diet: red flags and the real evidence
Sources
- USDA FoodData Central, for green kiwifruit nutrient values.
- Consumption of 2 Green Kiwifruits Daily Improves Constipation and Abdominal Comfort: an international multicentre randomised controlled trial, American Journal of Gastroenterology.
- American College of Gastroenterology, randomised comparative effectiveness trial of green kiwifruit, psyllium or prunes.
- Two Gold Kiwifruit Daily for Effective Treatment of Constipation in Adults: a randomised clinical trial, Nutrients.
- Journal of General Internal Medicine, evidence appraisal of the kiwifruit constipation trial including its funding limitations.
- Michigan Medicine Health Lab, Does Kiwifruit Help Chronic Constipation?
- US FDA, Daily Value on the Nutrition and Supplement Facts Labels.
Last reviewed and rewritten September 2026. Nutrient values are from USDA FoodData Central and rounded, and vary with variety, ripeness and size. This article is general information, not medical or dietetic advice. Do not stop or change prescribed medication, including aspirin or any anticoagulant, on the basis of anything you read here. If you have a latex or food allergy, take warfarin, form kidney stones, manage diabetes, or have persistent changes in bowel habit, speak to your doctor or registered dietitian. Suspected anaphylaxis is a medical emergency. How we research and check this content is described in our editorial process and sources cited policy.
