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Watercress Herb Extract

Also known as: Watercress, garden cress, Watercress Herb Extract, Nasturtium officinale

Overview

Watercress (Nasturtium officinale R. Br.) is an aquatic or semi-aquatic perennial plant belonging to the Brassicaceae family, widely recognized as a functional food and herbal supplement. It is exceptionally rich in bioactive compounds, including glucosinolates, isothiocyanates (such as phenethyl isothiocyanate), vitamins, and various antioxidants. Traditionally consumed as raw food, juice, or in extract forms, watercress is primarily valued for its potential antioxidant, anti-inflammatory, anticancer, and cardiovascular protective properties. While preclinical studies and some randomized controlled trials (RCTs) support these benefits, the overall clinical evidence is still emerging and somewhat limited. Recent systematic reviews of RCTs provide more robust data on its antioxidant and anti-inflammatory effects, though the quality of evidence can vary, with some studies having small sample sizes or methodological limitations. Despite these limitations, watercress continues to be a subject of significant scientific interest due to its diverse phytochemical profile.

Benefits

Watercress offers several evidence-based benefits, primarily driven by its rich content of bioactive compounds: - **Antioxidant and Anti-inflammatory Effects:** A 2025 systematic review of randomized controlled trials (RCTs) confirmed that watercress supplementation significantly improves antioxidant markers and reduces inflammation in humans over short-term follow-up. This robust evidence supports its role in modulating oxidative stress and inflammatory responses, making it beneficial for general health and conditions associated with chronic inflammation. The strength of evidence for this benefit is considered high, based on systematic reviews of RCTs. - **Cancer-related Effects:** Watercress contains high levels of glucosinolates and their derivatives, such as sulforaphane and phenethyl isothiocyanate, which have demonstrated promising anticancer activity. In vitro and animal studies show that watercress extracts can inhibit breast cancer cell invasion by suppressing matrix metalloproteinase-9 and induce apoptosis (programmed cell death) in skin cancer cells. While these preclinical findings are strong, human clinical evidence is still insufficient to confirm efficacy against cancer. - **Cardiovascular and Metabolic Health:** Preclinical studies suggest potential benefits in managing hyperlipidemia (high cholesterol) and hypertension (high blood pressure). However, human clinical trials in this area are limited and have yielded inconclusive results, requiring further research to substantiate these effects. - **Renal Stone Prevention:** Low-dose watercress extract has shown some preventive effects on renal stone formation in animal models. However, there is currently no human data to support this benefit, and more research is needed.

How it works

The therapeutic effects of watercress are primarily attributed to its bioactive compounds, particularly glucosinolates. Upon ingestion, these glucosinolates are hydrolyzed by the enzyme myrosinase into highly active isothiocyanates, such as phenethyl isothiocyanate (PEITC) and sulforaphane. These isothiocyanates exert their effects by modulating phase II detoxification enzymes, which are crucial for neutralizing harmful substances in the body. They also enhance the body's endogenous antioxidant defenses by upregulating antioxidant enzymes and directly scavenging reactive oxygen species. Furthermore, isothiocyanates can inhibit inflammatory pathways and selectively induce apoptosis in cancer cells, while also inhibiting enzymes involved in tumor invasion and metastasis. This multi-targeted action contributes to watercress's antioxidant, anti-inflammatory, and potential anticancer properties.

Side effects

Watercress is generally considered safe when consumed as food or in typical supplement doses. Clinical trials and systematic reviews have not reported significant adverse effects associated with its consumption. However, specific safety data for higher doses or concentrated extracts are limited, and further toxicological evaluations are recommended to confirm safety under these conditions. While not specifically documented for watercress, a general caution applies to herbal medicines regarding potential interactions with anticoagulant medications like warfarin. Individuals on such medications should exercise caution and consult a healthcare professional before incorporating watercress supplements into their regimen, as some compounds in plants can affect blood clotting. There are no known specific contraindications for watercress, but individuals with known allergies to plants in the Brassicaceae family (e.g., broccoli, cabbage) should consume it with caution. Pregnant or breastfeeding women should also consult their doctor before using watercress in supplemental forms due to limited specific safety data in these populations. Overall, while generally safe, prudence is advised, especially with concentrated forms or in individuals with pre-existing conditions or those on medication.

Dosage

Standardized dosing for watercress is not yet well-established, as clinical trials have utilized various forms and amounts. Studies included in reviews often involved watercress as part of the diet (e.g., raw leaves or juice) or as extracts. Typical doses in research settings have varied, but precise effective doses for specific health benefits require further investigation. For general health and antioxidant support, dietary intake of watercress is considered safe and beneficial. When considering concentrated extracts, the dosage should ideally be standardized for bioactive compounds, such as isothiocyanates, to ensure consistent effects. The timing of consumption and the form (raw, juiced, or extracted) may influence the bioavailability and overall effects of the active compounds. There are no clearly defined upper limits or safety thresholds for watercress, but as with any supplement, excessive intake of concentrated forms should be approached with caution until more comprehensive safety data are available. It is always advisable to follow product-specific recommendations or consult a healthcare professional for personalized dosage guidance.

FAQs

Is watercress effective against cancer?

Laboratory and animal studies show promising anticancer effects, particularly in inhibiting cancer cell invasion and inducing apoptosis. However, human clinical evidence is currently insufficient to confirm its efficacy against cancer.

Can watercress reduce inflammation?

Yes, randomized controlled trials indicate that watercress supplementation can significantly improve antioxidant markers and reduce inflammation in humans, supporting its role in modulating inflammatory responses.

Is it safe to consume daily?

Generally, yes, watercress is safe for daily consumption within typical dietary amounts. However, for concentrated extracts, more safety data are needed, and caution is advised.

Does cooking affect benefits?

Cooking may reduce the content of beneficial glucosinolates in watercress. Consuming it raw or lightly processed forms is generally recommended to preserve its bioactive compounds more effectively.

Research Sources

https://www.phcogrev.com/sites/default/files/PhcogRev_2019_13_25_10.pdf – This review by Clemente et al. (2019) synthesizes preclinical and clinical studies on watercress, highlighting its antioxidant, anticancer, and cardiovascular benefits. It emphasizes the need for more well-designed randomized controlled trials to confirm these effects in humans and to establish standardized dosing and safety profiles.
https://foodrevolution.org/blog/watercress-health-benefits/ – This article from Food Revolution summarizes various in vitro and animal studies on watercress, particularly focusing on its anticancer properties. It notes that watercress extracts can inhibit cancer cell invasion and induce apoptosis, but acknowledges the current lack of human clinical trials to validate these findings.
https://pubmed.ncbi.nlm.nih.gov/40488189/ – This systematic review by Wen et al. (2025) of randomized controlled trials (RCTs) investigates the effects of watercress supplementation. It concludes that watercress significantly improves antioxidant and anti-inflammatory markers in humans over short-term follow-up, providing robust evidence for these specific benefits.
https://pmc.ncbi.nlm.nih.gov/articles/PMC12141087/ – This article, likely a duplicate or related publication to the Wen et al. (2025) systematic review, also discusses the impact of watercress supplementation on antioxidant and anti-inflammatory markers. It supports the findings that watercress can positively influence these health parameters in human subjects.