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Kiwi Extract

Also known as: Actinidia deliciosa Extract, Kiwi extract, Kiwifruit extract

Overview

Kiwi extract is derived from the fruit of the kiwifruit plant (Actinidia deliciosa). It is a dietary supplement and functional food ingredient primarily used for gastrointestinal health, particularly for treating constipation and improving bowel function. The extract contains dietary fiber (both soluble and insoluble), vitamins (notably vitamin C), antioxidants, and enzymes such as actinidin. These components contribute to its effects on gut motility and stool consistency. Research on kiwi extract is moderately mature, with multiple randomized controlled trials (RCTs) and systematic reviews/meta-analyses focusing on its efficacy in managing constipation. While evidence is emerging, the overall certainty is limited by small sample sizes and heterogeneity in study designs. Kiwi extract is generally considered safe, with minor gastrointestinal discomfort being the most commonly reported side effect.

Benefits

Kiwifruit extract has demonstrated benefits in alleviating constipation and related symptoms. A meta-analysis of seven RCTs (399 participants) indicated that kiwifruit extract increased the frequency of spontaneous bowel movements (SBM) by a mean difference of 1.36 more weekly SBMs compared to placebo. However, the certainty of this evidence is low due to variability and confidence intervals crossing zero. Moderate certainty evidence suggests that kiwifruit extract reduces abdominal pain associated with constipation (standardized mean difference (SMD) -1.44; 95% CI: -2.83 to -1.66). Some evidence also points to a reduction in straining during defecation, although the effect sizes are smaller and less certain (SMD -0.29; 95% CI: -1.03 to 0.47). Studies have primarily focused on adults with functional constipation, predominantly middle-aged females. The observed increase in bowel movements, combined with reduced abdominal pain, may be clinically meaningful for constipated individuals.

How it works

Kiwi extract's mechanism of action involves several biological pathways. The fiber content increases stool bulk and water retention, facilitating bowel movements. Actinidin, a proteolytic enzyme, may enhance protein digestion and gut motility. Additionally, antioxidants and bioactive compounds may reduce gut inflammation and improve overall gut health. The extract primarily affects the gastrointestinal tract by modulating motility and stool characteristics. While fiber acts locally in the gut, enzymes and antioxidants may have systemic absorption, though their role in constipation relief is less clear.

Side effects

Kiwi extract is generally regarded as safe, with no serious adverse events reported in RCTs. The most common side effects are minor gastrointestinal discomfort, such as bloating or gas, though these are not well quantified. Individuals with a known allergy to kiwifruit should avoid the extract due to the risk of allergic reactions. No significant drug interactions have been reported. Most studies have excluded children and pregnant women, so the safety of kiwi extract in these populations is not well established. Caution is advised when considering kiwi extract for these groups.

Dosage

Dosage recommendations for kiwi extract vary. Some studies have used whole kiwifruit (2-3 fruits daily), while others have used encapsulated extracts with doses that are not standardized across studies. A minimum effective dose has not been definitively established, but studies suggest a daily intake equivalent to 2-3 kiwifruits. The extract is typically administered daily with meals. It is available in whole fruit form or as standardized extracts with defined fiber and enzyme content. The efficacy of fiber depends on adequate hydration. Specific upper limits and safety thresholds have not been formally established, but consumption within typical dietary amounts is considered safe.

FAQs

Is kiwi extract effective for constipation?

Yes, evidence supports modest improvement in bowel movement frequency and reduction in abdominal pain associated with constipation.

Are there risks of allergic reactions?

Yes, individuals allergic to kiwi should avoid the extract to prevent potential allergic reactions.

How long before effects are seen?

Benefits may appear within 2 weeks of consistent use and persist with continued intake of kiwi extract.

Can it replace laxatives?

It may serve as a natural alternative or adjunct but should not replace medical treatment without consultation with a healthcare provider.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC9560827/ – This systematic review and meta-analysis of 7 RCTs (399 adults with constipation) found that kiwifruit extract increased weekly spontaneous bowel movements (SBM) by a mean difference of 1.36 (95% CI -0.44 to 3.16) and reduced abdominal pain. The authors noted that the certainty of the evidence was low to moderate due to small sample sizes and heterogeneity among the included studies.
https://biomedpharmajournal.org/vol17no2/a-systematic-review-and-meta-analysis-of-kiwifruits-impact-on-functional-constipation/ – This systematic review and meta-analysis supports the use of kiwifruit as a safe and effective treatment for functional constipation. The authors call for more high-quality trials to further validate these findings and to explore the optimal dosage and duration of treatment.
https://academic.oup.com/jcag/article/5/Supplement_1/133/6533030 – This systematic review and meta-analysis confirms the benefits of kiwifruit or its extracts on constipation symptoms. The authors acknowledge that the findings are limited by study heterogeneity and small sample sizes, highlighting the need for more robust research in this area.
https://pubmed.ncbi.nlm.nih.gov/36247043/ – This study investigates the effects of kiwifruit consumption on bowel function. The research suggests that regular intake of kiwifruit can improve constipation symptoms and overall digestive health, supporting its use as a natural remedy for constipation.
https://onlinelibrary.wiley.com/doi/abs/10.1155/2022/7596920 – This research explores the potential of kiwifruit in managing digestive disorders. The findings indicate that kiwifruit's unique composition, including fiber and enzymes, contributes to its beneficial effects on gut health and bowel regularity.