Modulation of plasma antioxidant levels, glutathione S ‐transferase activity and DNA damage in smokers following a single portion of broccoli: a pilot study

BACKGROUND Broccoli is a rich source of bioactive compounds (i.e. glucosinolates, carotenoids, vitamin C and folate) that may exert an antioxidant effect and reduce oxidative damage. The objective of this pilot study was to investigate the effect of broccoli consumption on carotenoids, vitamin C and folate absorption, glutathione S ‐transferase ( GST ) activity, and oxidatively induced DNA damage in male smokers . METHODS Ten healthy subjects consumed a single portion of steamed broccoli (250 g) with cooked pasta. Blood was drawn at baseline and at 3, 6 and 24 h from consumption . RESULTS Broccoli significantly ( P ≤ 0.01) increased plasma level of vitamin C and folate (+35% and 70%, respectively) at 3 h, and β ‐carotene (+8%) at 6 h. A modulation of GST activity occurred in plasma 6 h after broccoli consumption. A significant ( P ≤ 0.01) reduction of the levels of H 2 O 2 ‐induced DNA damage (−18%) was observed in blood mononuclear cells 24 h after broccoli intake in GSTM1 positive, but not in GSTM1 null subjects . CONCLUSION One portion of broccoli increased plasma antioxidant levels, modulated plasma GST activity and improved cell resistance against H 2 O 2 ‐induced DNA damage in healthy smokers. These results support the importance of consuming fruit and vegetable regularly. © 2013 Society of Chemical Industry