How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Kiwi (fruit and powder)
Two kiwifruits per day help bowel transit, just as well as psyllium or prunes, and slightly lower blood pressure. Powders and capsule extracts have been tested less and their results are more fragile.
Benefits
- Helps bowel transit, fresh fruit: EFSA recognizes that it contributes to normal defecation; in six trials, 2 to 4 green kiwifruits per day increase stool frequency, without diarrhea.
- As effective as psyllium or prunes against chronic constipation: with 2 green kiwifruits per day for 4 weeks, more complete bowel movements, less straining, less bloating, and the fewest side effects of the three treatments; 2 gold kiwifruits do just as well as psyllium at equal fiber content.
- In extract form, relieves occasional constipation: in 58 adults, 7 days of green kiwifruit extract increased stool frequency and reduced abdominal pain compared to placebo, with no side effects.
- Slightly lowers blood pressure: -5.73 mmHg for systolic and -4.08 for diastolic across six trials; 3 kiwifruits per day for 8 weeks resulted in 3.6 and 1.9 mmHg lower over 24 hours than an apple in 118 people with moderately elevated pressure.
- Less fatigue when vitamin C is low: in 167 young adults, 2 SunGold kiwifruits per day reduced fatigue and improved well-being in 2 weeks, compared to placebo.
Precautions
The trials selected by EFSA did not cause diarrhea, and the extract tested for 7 days produced no side effects. Capsule extracts could increase minor adverse effects compared to placebo (relative risk of 4.58, with high uncertainty). Limitations: against constipation, the meta-analysis of 7 trials judges the evidence to be of low certainty, and the effect of extracts versus placebo on stool count remains uncertain. Not all powders work: 1 g per day of green kiwifruit extract changed nothing in constipated adults, and 2,400 mg per day did not increase stool output in the 9 constipated individuals of another trial. For cholesterol, the results are meager: a meta-analysis of 6 trials finds LDL lower by 9.30 mg/dL but nothing on total cholesterol, triglycerides, blood glucose, or weight; another, on 5 trials and 489 people, finds no effect. In 85 men with high cholesterol, 2 green kiwifruits per day raised HDL by only 0.04 mmol/L, without changing LDL or blood pressure. Faster and longer sleep (sleep onset 35.4% shorter, 13.4% more sleep) comes from trials without a control group, on 24 adults and elite athletes. In 32 people aged 65 and over, the equivalent of 4 gold kiwifruits per day did not reduce the number of ENT infections compared to banana, only the duration of certain symptoms. The meta-analysis on blood pressure counts only 6 trials, and in the 8-week trial, office-measured pressure did not change.
Recommended dosage
2 to 3 fresh kiwifruits per day (2 large green kiwifruits make about 200 g of flesh); in powder form, 2,400 mg per day in bowel transit trials.
How to take it
- Fruit or powder: most trials give the whole fruit; powders and capsule extracts have been tested less, and their results are more fragile.
- For bowel transit: 2 green kiwifruits per day, or 2 gold kiwifruits, for 4 weeks in the trials.
- In powder form: 2,400 mg per day for 28 days increased stool count in healthy adults, but not in constipated ones; 1 g per day of extract changed nothing.
- For blood pressure: 3 kiwifruits per day for 8 weeks; in the meta-analysis, the effect was clearer at 3 kiwifruits per day and when pressure was high at baseline.
- For fatigue: 2 SunGold kiwifruits per day, with an effect starting at 2 weeks in adults whose vitamin C was low.
- For sleep: both trials gave 2 kiwifruits one hour before bedtime for 4 weeks, without a control group (see limitations).
Did you know?
In an American trial on chronic constipation, two green kiwifruits per day performed just as well as psyllium and prunes, with the fewest side effects and the fewest dissatisfied patients of the three.
What the studies say
This meta-analysis evaluated the impact of kiwifruit consumption on blood pressure in adults. The combined analysis of six randomized controlled trials indicated that kiwifruit consumption led to a significant reduction in systolic and diastolic blood pressure. This effect was more pronounced in individuals with elevated baseline blood pressure, a normal BMI, and receiving higher doses (3 kiwifruits/day).
Mohammadi SG, Haghighat N, Dehghani A, Rafiei MM, Pam P, Amirkhan-Dehkordi M, Goudarzi MA, Asbaghi O, Naderian M, Hosseini A, Karimi M. — Health science reports (2026) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more