Watercress capsules and blood metabolites in a 28-day trial
What it found
In 26 middle-aged Thai adults, taking dried watercress capsules for 28 days was linked to changes in many blood metabolites and a drop in LDL cholesterol.
The authors call the results early and in need of confirmation.
What they found
Studies in people
LDL cholesterol
LDL cholesterol fell in the watercress group and rose in the placebo group over the 28 days. This difference remained significant after adjusting for multiple comparisons.
Metabolite changes
The researchers identified 209 plasma metabolites and found 27 that differed most between groups. Nineteen of these remained significant after correction.
Carbohydrate pathways
Galactose and fructose/mannose metabolism were the most strongly affected pathways. Changes were also seen in glycolysis and the pentose phosphate pathway.
Tryptophan and inflammation
Metabolites in the tryptophan-kynurenine pathway, including L-kynurenine, decreased. This pathway is linked to inflammation, but inflammatory markers were not measured.
Oxidative DNA damage
A marker of oxidative DNA damage, 8-oxo-dGMP, was reduced. The authors say this is consistent with antioxidant effects seen in earlier watercress studies.
Gut microbial metabolism
Indoxyl sulfate and shikimic acid, which come from gut microbial metabolism, were reduced. The study did not profile the microbiome, so the source of these changes is unclear.
What the authors conclude
“Watercress supplementation was associated with coordinated metabolic alterations across multiple pathways, generating mechanistic hypotheses for its antioxidant and cardiometabolic effects.”
Also in their conclusions
- They say watercress supplementation was associated with coordinated metabolic alterations across multiple pathways, generating hypotheses for its antioxidant and cardiometabolic effects.
- They state that these findings are exploratory and warrant confirmation in larger, adequately powered clinical trials.
- They advise that larger trials with targeted metabolite measurement, multi-omics, microbiome profiling, and cardiovascular biomarkers are needed to validate the candidate metabolic signatures.
How it was done
Watercress is rich in glucosinolates and has been studied for heart benefits, but earlier human studies only looked at a few pre-chosen markers. The authors wanted a broader picture of what changes in the blood after taking it.
They gave 26 Thai adults aged 40 to 59 with low-to-moderate heart risk either dried watercress capsules (8 g a day, about 195 mg glucosinolates) or placebo for 28 days. Blood samples taken before and after were analysed for a wide range of metabolites.
What it can’t tell you
- The study was small (26 people) and short (28 days), so it cannot show whether these metabolite changes lead to any long-term health effect.
- The authors did not measure inflammatory markers, gut bacteria, or detailed diet, so they cannot say what caused the metabolite differences.
- The findings are exploratory and need to be confirmed in larger trials before any conclusions can be drawn.
Who paid
- Funding
- Funded by Chiang Mai University (from the PubMed record).
- Conflicts
- The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
- Authors work at
- Chiang Mai University, Thailand; Malawi College of Health Sciences, Malawi
The paper
- Title
- Untargeted 1 H-NMR Metabolomics Identifies Candidate Metabolic Changes Associated with Watercress ( Nasturtium officinale R.Br.) Supplementation in Adults with Low-to-Moderate Cardiovascular Risk: A Randomized Placebo-Controlled Trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Maluwa C, Zinan'dala B, Kijkuokool P, et al (2026). Untargeted 1 H-NMR Metabolomics Identifies Candidate Metabolic Changes Associated with Watercress ( Nasturtium officinale R.Br.) Supplementation in Adults with Low-to-Moderate Cardiovascular Risk: A Randomized Placebo-Controlled Trial. Nutrients. doi:10.3390/nu18152559Free full textPubMed 42588182DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error