Watercress
A peppery, near-zero-calorie cruciferous green that delivers an outsized hit of vitamin K, vitamin C and the carcinogen-detoxifying isothiocyanate PEITC.
Moderate evidence
🥦Vegetables
Evidence tier
Moderate
Research weight
Citations
11 verified / 11
Classification
Vegetables
❝
What the evidence says. Several controlled trials; effects real but modest or context-dependent.
Nutrition per serving 1 cup chopped, raw (34 g)
- Sugars 0.1 g0%
- Fibre 0.2 g1%
- Other carbs 0.1 g0%
- Protein 0.8 g2%
- Other 32.8 g96%
3.7 kcal0.8 g protein0.2 g fiber0.07 g sugar
| Nutrient | Per serving | % daily value |
|---|---|---|
| Vitamin C | 15 mg | 16% |
| Fiber | 0.2 g | 1% |
| Potassium | 112 mg | 2% |
| Folate | 3 µg | 1% |
| Vitamin A | 54 µg | 6% |
| Vitamin K | 85 µg | 71% |
| Vitamin B6 | 0.04 mg | 3% |
| Manganese | 0.08 mg | 4% |
| Copper | 0.03 mg | 3% |
| Vitamin E | 0.34 mg | 2% |
| Magnesium | 7 mg | 2% |
| Calcium | 41 mg | 3% |
Composition data: USDA FoodData Central ↗
What is Watercress?
Watercress is a vegetable used for enhances detoxification of environmental and tobacco carcinogens (peitc). NutriDex grades the human evidence as Moderate. Watercress is a nutrient-dense cruciferous leaf whose signature bioactive, phenethyl isothiocyanate (PEITC, from gluconasturtiin), has been tested in human trials. A randomized crossover study showed 85 g/day of raw watercress for 8 weeks cut lymphocyte DNA damage and roughly doubled plasma lutein, and randomized phase-2 trials of PEITC or a freeze-dried watercress beverage significantly boosted urinary detoxification of tobacco-related and environmental carcinogens (acrolein, benzene, crotonaldehyde) and modestly inhibited activation of the lung carcinogen NNK in smokers. Large prospective cohorts and meta-analyses of cruciferous vegetables as a class link higher intake to lower cardiovascular and colorectal-cancer risk, though watercress-specific hard-outcome data remain limited.
Purported Benefits
✓Enhances detoxification of environmental and tobacco carcinogens (PEITC)
✓Reduces lymphocyte DNA damage and oxidative stress
✓Raises plasma carotenoids (lutein, beta-carotene)
✓Cruciferous intake linked to lower CVD and colorectal-cancer risk
✓Exceptional vitamin K and vitamin C density at near-zero calories
Dosing & Compounds
Typical Dose
Standard serving: 1 cup chopped, raw (34 g). Eat whole (with skin where edible); favour whole fruit over juice.
Active Compounds
Safety & Cautions
Very high in vitamin K1 (~85 ug per cup) — people on warfarin should keep intake consistent to avoid destabilizing INR. As a raw cruciferous green it contains goitrogenic glucosinolates, of possible concern only at very high intakes with iodine deficiency. Generally well tolerated; wild-harvested watercress can carry liver-fluke (Fasciola) or waterborne-pathogen risk, so use cultivated/washed produce. Educational only — always check with your doctor or pharmacist before combining Watercress with any medicine.
Key Studies ★ 11 studies
Systematic review
Wen 2025 (Food Sci Nutr)
✓ Full text
Systematic review of RCTs found watercress supplementation improved antioxidant and anti-inflammatory markers at short-term follow-up, though effects were modest and evidence limited by small trial sizes.
Meta-analysis
Pollock 2016 (meta-analysis)
✓ Full text
Meta-analysis reported green-leafy and cruciferous vegetable intake associated with ~15.8% lower cardiovascular-disease incidence (RR 0.842, 95% CI 0.753-0.941, P=0.002).
Meta-analysis
Wu 2013 (meta-analysis)
✓ PubMed
Meta-analysis of observational studies found higher cruciferous-vegetable intake associated with a significantly lower colorectal-cancer risk (RR 0.82, 95% CI 0.75-0.90).
RCT
Maluwa 2026
✓ PubMed
Placebo-controlled RCT identified candidate metabolomic changes with watercress supplementation in adults with low-to-moderate cardiovascular risk.
RCT (randomized crossover)
Hecht / watercress-beverage trial 2026 (RCT)
✓ Source
Two-site randomized crossover (188 completers) of a freeze-dried watercress beverage (2 wk) significantly increased urinary mercapturic-acid detoxification of acrolein (+65.6%) and benzene (+37.3%) plus other toxicants versus placebo.
RCT (phase 2 crossover)
Hecht 2016 (RCT)
✓ Full text
Randomized phase-2 crossover in 82 smokers: PEITC (the watercress isothiocyanate) produced a modest but significant 7.7% inhibition of metabolic activation of the lung carcinogen NNK versus placebo.
RCT (randomized crossover)
Fogarty 2013 (RCT)
✓ Source
Acute and 8-wk chronic watercress supplementation in trained men (n=10) attenuated exercise-induced peripheral mononuclear-cell DNA damage and lipid peroxidation versus control.
RCT (randomized crossover)
Gill 2007 (RCT)
✓ PubMed
85 g/day raw watercress for 8 wk in 60 adults reduced basal lymphocyte DNA damage by 17% (P=0.03) and oxidative purine DNA damage by 23.9% (P=0.002), with plasma lutein +100% and beta-carotene +33% (P<0.001).
Review
Watercress functional food review 2025 (Life/MDPI)
✓ Full text
Narrative review of 88 sources (2019-2025) summarizing watercress glucosinolate/PEITC effects on non-communicable diseases, noting antioxidant, anti-inflammatory, and metabolic effects while emphasizing scarcity of robust human trials.
Observational
Charron 2022 (Cancer Prev Res)
✓ PubMed
Methods paper describing preparation of a standardized freeze-dried watercress beverage delivering reproducible PEITC for the NCT03978117 carcinogen-detoxification clinical trial.
Prospective cohort
Zhang 2011 (cohort)
✓ Full text
In 134,796 Chinese adults, highest vs lowest cruciferous-vegetable intake was associated with lower total mortality (HR 0.78, 95% CI 0.71-0.85) and cardiovascular mortality (HR 0.69, 95% CI 0.56-0.85).