Watercress juice and how fast people clear its compounds
What it found
People with two different gene types cleared watercress compounds from their bodies at about the same speed.
The trial involved 48 adults who drank watercress juice.
What they found
Studies in people
Clearing compounds from the body
Both groups got rid of the watercress compounds at about the same speed. There was no meaningful difference in the total amount cleared or when the highest level appeared in urine.
Other findings
Making the watercress juice
Researchers blended store-bought watercress with tap water at a ratio of 1:4 by weight. They filtered it through cheesecloth and kept it chilled until use.
Compound levels varied in juice
The amount of active compounds in the juice ranged widely from 15 to 206 µM, averaging 72 µM. This happened partly because the compounds broke down quickly during storage and because different batches of watercress varied.
What the authors conclude
- They conclude that having or lacking these specific genes does not change how fast the body clears the main compound found in watercress.
- Their results suggest that other unknown processes must explain why people without these genes seem to get more protection from eating cruciferous vegetables.
- They call for more research to figure out exactly how these plant compounds interact with our genes.
How it was done
Past research suggested that people missing certain genes might get more cancer protection from cruciferous vegetables. Scientists thought this could happen because those people clear the plant compounds more slowly, keeping them in the body longer.
They recruited 48 adults aged 18 to 60, split into two groups based on whether they had or lacked specific genes. Everyone avoided foods containing these compounds for 72 hours, then drank 200 ml of watercress juice. Researchers collected urine five times over the next 24 hours to measure how fast the compounds left the body.
What it can’t tell you
- This trial only looked at how fast the body clears one type of compound from watercress.
- It cannot show whether drinking watercress juice prevents cancer in people.
Who paid
- Funding
- Funded by NCI NIH HHS (from the PubMed record).
- Conflicts
- Conflict of interest . There are no conflicts of interest to disclose.
- Authors work at
- Georgetown University Medical Center, USA
The paper
- Title
- Metabolism of isothiocyanates in individuals with positive and null GSTT1 and M1 genotypes after drinking watercress juice
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Dyba M, Wang A, Noone AM, et al (2010). Metabolism of isothiocyanates in individuals with positive and null GSTT1 and M1 genotypes after drinking watercress juice. Clinical nutrition (Edinburgh, Scotland). doi:10.1016/j.clnu.2010.06.010Free full textPubMed 20656381DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error