Banim et al. have found that consuming a combination of the three highest quartiles (Q2–4) of vitamin C, vitamin E and selenium is associated with a decreased risk of pancreatic cancer. Threshold effects (Q2–4 versus Q1) were also found for selenium and vitamin E; serum measurements showed a decreased risk for vitamin C, but the threshold effect from 7-day food diaries was not significant. The authors estimate 1 in 12 cancers might be prevented by avoiding the lowest intakes of dietary antioxidants if the association is causal.