Table 1

Urinary nicotine metabolites (μmol/24 h) in smokers who consumed watercressa

Urinary metaboliteμmol/24 h (mean ± SD)
Period 1 (baseline)bPeriod 2 (watercress consumption)bPeriod 3 (follow-up 1)cPeriod 4 (follow-up 2)cP, Period 1 vs. period 2
Nicotine7.24 ± 3.416.56 ± 5.878.17 ± 7.235.91 ± 3.210.62
Nicotine-Gluc1.72 ± 1.032.48 ± 2.001.44 ± 0.7531.21 ± 0.9470.13
Cotinine10.3 ± 4.6710.0 ± 4.409.55 ± 7.007.65 ± 4.010.76
Cotinine-Gluc7.67 ± 5.769.60 ± 7.367.24 ± 4.397.58 ± 5.280.031
trans-3′-Hydroxycotinine34.7 ± 21.837.5 ± 17.130.9 ± 21.928.0 ± 15.40.50
trans-3′-Hydroxycotinine-Gluc8.29 ± 7.1611.0 ± 7.197.93 ± 7.237.38 ± 5.780.0043
Keto acid1.49 ± 1.001.66 ± 0.844NAdNA0.31
Hydroxy acid6.84 ± 3.867.22 ± 3.85NANA0.74
  • a Twelve smokers maintained constant smoking habits and avoided cruciferous vegetables except during the watercress consumption period. Twenty-four-h urine samples were collected and analyzed for nicotine metabolites (see Fig. 2<$REFLINK> ).

  • b For each smoker (n = 12), we determined the mean value of each metabolite (except keto acid and hydroxy acid) for the 3 days of the period. Then, the mean ± SD for the 12 smokers was calculated. Values for keto acid and hydroxy acid were from a single day in the period.

  • c The same as Footnote b except n = 10 smokers.

  • d NA, not analyzed.