Brussels sprouts and detox enzymes in the blood of ten people
What it found
Eating 300 g of cooked Brussels sprouts a day for one week raised a liver enzyme called GST class-a by 1.5-fold in men but not in women.
This was measured in ten healthy non-smoking volunteers.
What they found
Studies in people
Liver enzyme rose in men
After the Brussels sprouts week, men had 1.5 times more GST class-a in their blood plasma compared with the control week. The authors say this rise likely came from the liver rather than the stomach, intestine or kidney.
No change seen in women
Women showed no rise in blood levels of GST class-a after eating Brussels sprouts. The authors suggest men respond more strongly than women to these vegetables in terms of boosting liver enzymes.
Other enzyme stayed steady
Blood levels of a second enzyme, GST class-pi, did not change in either men or women during the Brussels sprouts week.
Urine levels unchanged
Amounts of both enzymes found in urine stayed about the same whether people ate Brussels sprouts or not. The authors say urine levels do not seem useful for tracking changes in liver enzymes caused by diet.
What the authors conclude
- They conclude that the rise in blood GST class-a seen in men probably comes only from the liver.
- They suggest that men are more responsive than women to the enzyme-boosting effects of Brussels sprouts on the liver.
- They advise that measuring these enzymes in urine is not a helpful way to track how diet affects liver enzymes.
How it was done
Diets rich in cruciferous vegetables like Brussels sprouts are linked to a lower risk of gut cancers. Scientists think compounds in these vegetables may boost enzymes that help the body clear harmful chemicals.
Ten healthy non-smoking adults, five men and five women, took part in a crossover trial. For one week they ate either 300 g of cooked Brussels sprouts daily or a diet free of similar compounds, then swapped diets for another week. Blood and urine samples were taken at the end of each week.
What it can’t tell you
- This trial involved only ten people, so the results might not apply to everyone.
- The study lasted just two weeks, so it cannot show what happens when people eat Brussels sprouts over many months or years.
Who paid
- Authors work at
- University Hospital St Radboud, The Netherlands
The paper
- Title
- Effects of consumption of brussels sprouts on plasma and urinary glutathione S-transferase class-alpha and -pi in humans
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Nijhoff WA, Mulder TP, Verhagen H, van Poppel G, Peters WH (1995). Effects of consumption of brussels sprouts on plasma and urinary glutathione S-transferase class-alpha and -pi in humans. Carcinogenesis. doi:10.1093/carcin/16.4.955Free full textPubMed 7728980DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error