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Key Lime Extract

Also known as: Key lime, Mexican lime, West Indian lime, Key lime extract, Citrus aurantifolia

Overview

Key lime extract is derived from the juice, peel, or whole fruit of Citrus aurantifolia, a small citrus fruit known for its rich content of vitamin C, flavonoids, and organic acids like citric acid. It is primarily investigated for its potential antioxidant, antimicrobial, anti-inflammatory, and weight management properties. The extract contains various bioactive compounds, including flavonoids, limonoids, and essential oils, which are believed to contribute to its biological effects. While research on key lime extract is emerging, with some clinical trials and in vitro studies, much of the evidence often considers broader citrus extracts rather than key lime specifically. The quality of evidence varies, with meta-analyses available for general citrus extracts, but high-quality randomized controlled trials (RCTs) focusing solely on key lime extract are limited.

Benefits

Key lime extract, or broader citrus extracts, offer several potential benefits. For **weight management**, a meta-analysis of 13 RCTs involving 921 adults showed that citrus extract supplementation for at least 4 weeks led to significant reductions in body weight (-1.28 kg), BMI (-0.32 kg/m²), waist circumference (-2.19 cm), and hip circumference (-2.14 cm). This suggests a modest but statistically significant effect on weight control, though this evidence is not exclusive to key lime. For **antimicrobial activity**, in vitro studies have demonstrated key lime extract's ability to inhibit the growth of *Helicobacter pylori*, including triple drug-resistant strains, and significantly reduce urease activity. This indicates potential for managing gastrointestinal infections, but clinical trials in humans are needed. Citrus fruits, including limes, also provide **anti-inflammatory and immune support** due to their vitamin C and flavonoid content, which may modulate inflammation and bolster immune function, though human data are still preliminary. The citric acid in lime may also contribute to **kidney stone prevention** by increasing urinary citrate, which helps prevent stone formation, but direct clinical evidence for key lime extract in this area is limited.

How it works

The proposed mechanisms of action for key lime extract's benefits are multifaceted. Its potential weight loss effects are hypothesized to involve flavonoids and limonoids that modulate lipid metabolism, enhance energy expenditure, and reduce the formation of fat cells (adipogenesis). The antimicrobial properties are linked to bioactive compounds that disrupt bacterial cell walls and inhibit urease, an enzyme crucial for the survival of bacteria like *H. pylori*. Vitamin C and flavonoids act as potent antioxidants, reducing oxidative stress, and as anti-inflammatory agents by modulating inflammatory mediators. Furthermore, the citric acid present in key lime increases urinary citrate levels, which binds to calcium and inhibits the formation of kidney stones. The absorption of these active compounds varies, with vitamin C being well absorbed, while flavonoid bioavailability depends on metabolism and the gut microbiota.

Side effects

Key lime extract is generally considered safe when consumed in dietary amounts or as a supplement within typical studied doses. Adverse effects are rare but may include mild gastrointestinal discomfort, such as stomach upset, or allergic reactions in individuals sensitive to citrus fruits. There are no significant drug interactions or contraindications that have been documented in high-quality scientific studies specifically for key lime extract. However, it's important to note that specific safety data for concentrated key lime extracts are lacking for special populations, including pregnant or lactating women and children. Therefore, caution is advised for these groups, and consultation with a healthcare professional is recommended before use. While excessive intake of vitamin C (above 2000 mg/day) can lead to side effects like diarrhea, nausea, and abdominal cramps, this is generally not a concern with typical key lime extract supplementation.

Dosage

There is no universally established maximum safe dose specifically for key lime extract, as research often pools it with other citrus extracts. The meta-analysis on weight management included studies with at least 4 weeks of citrus extract supplementation, but exact dosing for key lime extract alone was not consistently specified. Typical vitamin C content in lime juice is about 22% of the daily value per fruit. Supplement doses in studies are often standardized to their flavonoid or vitamin C content rather than a specific amount of key lime extract. When considering supplementation, doses should align with general guidelines for citrus extracts. It is advisable to avoid excessive vitamin C intake, which is generally considered to be above 2000 mg per day, to prevent potential side effects. The timing of supplementation and the form of the extract (e.g., juice, peel extract, capsules) can influence bioavailability, but further research is needed to optimize these factors.

FAQs

Is key lime extract effective for weight loss?

Evidence from broader citrus extracts suggests modest benefits for weight loss, but high-quality randomized controlled trials specifically on key lime extract are currently limited.

Can key lime extract replace antibiotics for *H. pylori* infection?

No, while in vitro studies show promising antimicrobial effects against *H. pylori*, clinical efficacy and safety in humans need to be confirmed through further research before it can be considered a treatment.

Is it safe to consume key lime extract daily?

Yes, within dietary amounts and typical supplement doses, key lime extract is generally considered safe for daily consumption. However, the safety of very high-dose extracts is less studied.

Does drinking lime water provide similar benefits?

Lime water offers vitamin C and hydration benefits, potentially aiding in kidney stone prevention and immune support. It provides some benefits, but concentrated extracts may offer higher levels of specific bioactive compounds.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/32182635/ – This meta-analysis of 13 randomized controlled trials (n=921) investigated the effects of citrus extracts on body weight and composition. It found that citrus extract supplementation for at least 4 weeks significantly reduced body weight, BMI, waist circumference, and hip circumference. While comprehensive, the study noted high heterogeneity and pooled various citrus extracts, meaning the findings are not specific to key lime alone.
https://pmc.ncbi.nlm.nih.gov/articles/PMC5961513/ – This in vitro laboratory study demonstrated that key lime extract effectively inhibited the growth of *Helicobacter pylori*, including drug-resistant strains. It also significantly reduced urease activity, an enzyme critical for *H. pylori* survival. The study provides strong evidence for the antimicrobial potential of key lime extract but lacks human clinical data.
https://www.medicalnewstoday.com/articles/322556 – This narrative review discusses the general health benefits of lime, highlighting its content of vitamin C and citric acid. It suggests potential anti-inflammatory properties and a role in kidney stone prevention. However, it is not a systematic review and lacks specific randomized controlled trial data for key lime extract, making it more hypothesis-generating than evidence-based for concentrated extracts.