Get Your Personalized Supplement StackSupplement Stack Quiz

Kiwi Fruit

Also known as: Kiwi fruit, Chinese gooseberry, Actinidia deliciosa

Overview

Kiwi fruit, scientifically known as Actinidia deliciosa, is an edible berry originating from China and now widely cultivated globally. It is consumed fresh, as juice, extracts, or in various processed forms. Primarily recognized for its rich nutritional profile, kiwifruit is an excellent source of vitamin C, dietary fiber, polyphenols, and essential minerals. As a functional food ingredient and dietary supplement, it has garnered attention for its potential benefits, particularly in improving gastrointestinal function, specifically constipation relief, and exhibiting cardiometabolic effects. Its antioxidant and anti-inflammatory properties, attributed to its high vitamin C and polyphenol content, also contribute to its overall health-promoting attributes. Research on kiwifruit is moderate, with several randomized controlled trials and systematic reviews supporting its use for certain conditions, though the certainty of evidence varies.

Benefits

Kiwifruit offers several evidence-based benefits, primarily for gastrointestinal health and lipid metabolism. A systematic review and meta-analysis of 7 randomized controlled trials (RCTs) indicated that kiwifruit or its extracts may increase spontaneous bowel movements (SBM) by approximately one additional SBM per week compared to placebo or psyllium, with low to moderate certainty evidence. This review also found that kiwifruit reduced abdominal pain with moderate certainty and improved stool softness with low certainty, making it a clinically relevant option for managing functional constipation or IBS-C. Furthermore, a meta-analysis suggested that while kiwifruit consumption did not significantly impact anthropometric indices or most cardiometabolic factors, it did lead to a significant reduction in LDL cholesterol levels. Beyond these primary effects, kiwifruit's high content of vitamin C and polyphenols contributes to its antioxidant activity, potentially supporting general health and reducing oxidative stress. The benefits for constipation are most pronounced in adults with functional constipation or IBS-C, predominantly observed within 4 to 12 weeks of consistent consumption.

How it works

The primary mechanism of action for kiwifruit's gastrointestinal benefits lies in its high dietary fiber content. This fiber increases stool bulk and water content, which facilitates easier bowel movements and improves stool consistency. The fruit's polyphenols and vitamin C contribute to its antioxidant and anti-inflammatory effects, which may support overall gut health and reduce oxidative stress throughout the body. While the exact molecular targets are not fully elucidated, the fiber also influences the gut microbiota and motility. For its potential lipid-lowering effects, kiwifruit is thought to modulate cholesterol metabolism, leading to a reduction in LDL cholesterol. The bioavailability of vitamin C and polyphenols from kiwifruit allows these compounds to exert their systemic effects, though bioavailability can be influenced by processing and digestion.

Side effects

Kiwifruit is generally considered safe when consumed as food or a supplement. The most commonly reported side effects are minor gastrointestinal symptoms, such as mild bloating, which are infrequent and typically mild. Some studies have noted a slight increase in minor adverse events with kiwifruit extracts compared to placebo, though these events were not severe. Rare but possible side effects include allergic reactions, particularly in individuals with a known allergy to kiwifruit or those with latex-fruit syndrome, due to cross-reactivity. There are no well-documented significant drug interactions associated with kiwifruit consumption. Contraindications primarily include individuals with a confirmed allergy to kiwifruit. Caution is advised for individuals with known allergies, as data on special populations is limited. Overall, serious adverse events are rare, and kiwifruit is well-tolerated by most individuals.

Dosage

For constipation relief, studies have shown efficacy with daily consumption of approximately 2 to 4 whole kiwifruits or equivalent doses of standardized extracts. There is no established maximum safe dose, as typical dietary consumption is considered safe. For optimal benefits, daily consumption is recommended, and the timing relative to meals does not appear to be critical. While whole fruit provides the full spectrum of nutrients and fiber, extracts have also been studied and show benefits, though they may be associated with a slightly higher incidence of minor adverse events. It's important to note that processing can affect the content and bioavailability of beneficial compounds like vitamin C and polyphenols. There are no specific cofactors identified as necessary for kiwifruit's efficacy.

FAQs

Is kiwifruit effective for constipation?

Evidence suggests kiwifruit can modestly increase bowel movements and reduce abdominal pain, offering a natural option for mild constipation, though evidence certainty is low to moderate.

Is it safe to consume kiwifruit daily?

Yes, kiwifruit is generally safe for daily consumption. Minor gastrointestinal side effects like bloating are possible but rare and typically mild.

How soon can benefits be expected from kiwifruit?

Benefits, particularly for constipation, are typically observed within weeks of consistent daily consumption, with studies ranging from 4 to 12 weeks.

Can kiwifruit replace laxatives?

Kiwifruit can be a complementary approach for mild constipation but should not replace prescribed medical treatments or laxatives for severe cases without professional advice.

Are kiwifruit extracts as effective as whole fruit?

Extracts show some benefits, but whole fruit provides more fiber and nutrients. Extracts might also have a slightly higher incidence of minor adverse events compared to whole fruit.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC11521643/ – This meta-analysis investigated the cardiometabolic effects of kiwifruit consumption. It found no significant impact on anthropometric indices or most cardiometabolic factors, but a significant reduction in LDL cholesterol levels. The study used a random effects model and included sensitivity analyses, though limitations included heterogeneity and short trial durations.
https://pubmed.ncbi.nlm.nih.gov/36247043/ – This systematic review and meta-analysis, which is also referenced as PMC9560827, focused on kiwifruit's efficacy for constipation. It included 7 RCTs (n=399) and found that kiwifruit or its extracts increased spontaneous bowel movements by approximately one per week and reduced abdominal pain. The study noted limitations due to small sample sizes and low to moderate evidence certainty.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9560827/ – This systematic review and meta-analysis, also referenced as PubMed ID 36247043, evaluated kiwifruit for constipation. It concluded that kiwifruit or extracts increased spontaneous bowel movements and reduced abdominal pain, with moderate certainty for pain reduction. The study highlighted the need for larger, higher-quality trials due to current limitations in sample size and evidence certainty.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6458959/ – This study investigated the nutritional composition and bioavailability of vitamin C, polyphenols, and minerals in kiwifruit and its products using in vitro digestion models. It emphasized that processing can affect the content and bioavailability of these compounds, which in turn influences their biological effects. A limitation is that it was an in vitro study, lacking direct clinical correlation.