Watercress Leaf Powder
Also known as: Watercress, garden cress, yellowcress, Watercress leaf powder, Nasturtium officinale
Overview
Watercress leaf powder is derived from the dried or freeze-dried leaves of *Nasturtium officinale*, an aquatic cruciferous plant. It is recognized as a functional food due to its rich content of vitamins (A, C, K), minerals, and bioactive phytochemicals, notably phenethyl isothiocyanate (PEITC) and flavonoids. This supplement is utilized for its antioxidant, anti-inflammatory, and potential anticancer properties, as well as for supporting cardiovascular and skin health. The powdered form offers advantages in standardized dosing and extended shelf life compared to fresh leaves. While research on watercress is evolving, with a growing number of preclinical and clinical studies, specific systematic reviews on watercress leaf powder supplementation remain limited. The quality of evidence varies, with a need for more rigorous, well-powered human trials.
Benefits
Watercress leaf powder offers several evidence-based benefits. It demonstrates significant antioxidant and anti-inflammatory effects, with a recent systematic review of randomized controlled trials (RCTs) indicating improvements in markers of oxidative stress and inflammation, supporting its role in reducing systemic damage. Consumption of cruciferous vegetables, including watercress, is associated with approximately a 20% lower risk of lung cancer, likely due to PEITC's ability to modulate carcinogen metabolism and induce apoptosis. For cardiovascular health, its nitrate content may enhance nitric oxide bioavailability, promoting vasodilation and potentially improving vascular function. Additionally, its vitamin A and isothiocyanate content contributes to skin cell protection, inflammation reduction, and potential skin cancer prevention. Preliminary evidence also suggests roles in managing hyperlipidemia, hypertension, and preventing renal stones, though these require further clinical validation.
How it works
The therapeutic effects of watercress leaf powder are primarily attributed to its bioactive compounds, including phenethyl isothiocyanate (PEITC), flavonoids, and various vitamins. These compounds exert antioxidant effects by scavenging free radicals and upregulating the body's endogenous antioxidant enzymes. PEITC plays a crucial role in modulating phase I and II detoxification enzymes, which aids in the elimination of carcinogens and can induce apoptosis in cancer cells. The nitrate content in watercress is converted into nitric oxide within the body, leading to vasodilation and improved endothelial function. Its anti-inflammatory actions are mediated through the downregulation of pro-inflammatory cytokines and inhibition of NF-κB signaling pathways, contributing to reduced systemic inflammation. Freeze-drying effectively preserves the PEITC content, ensuring its bioactivity.
Side effects
Watercress leaf powder is generally considered safe when consumed in typical dietary amounts or as a supplement within studied dosages. Clinical trials and reviews have not reported significant adverse effects, and both topical and oral uses have shown good tolerability. However, due to its vitamin K content, individuals taking anticoagulant medications (blood thinners) should monitor their intake and consult with a healthcare provider, as vitamin K can interfere with these medications. While no serious contraindications have been reported, caution is advised for individuals with thyroid disorders due to the goitrogenic potential of cruciferous vegetables, which could theoretically interfere with thyroid function, although this is typically a concern with very high consumption. Overall, it has a favorable safety profile, but professional medical advice is recommended for those with pre-existing conditions or on specific medications.
Dosage
Clinical studies have typically utilized doses of approximately 98 grams of freeze-dried watercress powder per week, which translates to about 14 grams per day. These dosages are often standardized for their PEITC content. It is important to note that an optimal dosing regimen is not yet firmly established, and dosages used in trials can vary depending on the specific research objective and the concentration of bioactive compounds in the preparation. For best preservation of bioactivity, freeze-dried powder should be stored refrigerated or frozen. While no specific cofactors are required for absorption, consuming the powder with meals may enhance its bioavailability. Users should consider the concentration of active compounds in their specific product and consult with a healthcare professional for personalized guidance, especially when addressing specific health concerns.
FAQs
Is watercress leaf powder effective for cancer prevention?
Evidence suggests potential benefits, particularly for reducing lung cancer risk, but it should not be considered a substitute for conventional medical cancer treatments.
Can it improve athletic performance?
Some research indicates nitrate-mediated vascular benefits that might aid performance, but findings are mixed, and more definitive studies are needed.
Is it safe to consume daily?
Yes, within studied dosages, daily consumption is generally safe. However, individuals on anticoagulant medications should consult their healthcare provider.
How soon do benefits appear?
Antioxidant and anti-inflammatory effects have been observed in short-term studies, typically within a few weeks of consistent supplementation.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8898268/ – This source, likely Zhang et al., 2022, details pilot trials on freeze-dried watercress, establishing its PEITC content. It also references a meta-analysis linking cruciferous vegetable intake to a 20% lower lung cancer risk, providing a basis for watercress's potential anti-cancer properties.
- https://www.phcogrev.com/sites/default/files/PhcogRev_2019_13_25_10.pdf – This review (PhcogRev, 2019) synthesizes preclinical and clinical studies on watercress, highlighting its antioxidant, anti-inflammatory, and potential benefits for chronic diseases. It emphasizes the need for more large-scale randomized controlled trials to confirm efficacy and establish optimal dosing.
- https://pubmed.ncbi.nlm.nih.gov/40488189/ – This citation, likely Wen et al., 2025, refers to a systematic review of RCTs demonstrating that watercress supplementation significantly improved markers of oxidative stress and inflammation. It provides strong evidence for watercress's role in reducing systemic oxidative damage and inflammatory status.
- https://www.stylecraze.com/articles/watercress-benefits-for-skin-hair-health/ – This source discusses the benefits of watercress for skin and hair health, attributing them to its vitamin A and isothiocyanate content. It suggests protective effects against skin cell damage and inflammation, and potential for skin cancer prevention.