We explored publication bias using a funnel plot
taking into account that this graphical method may not
be ideal in detecting publication bias when the number of
studies is small as in our meta-analysis. In spite of the absence of symmetry in Fig. 3, the funnel plot, which
relates the magnitude of the RR of each study to the
inverse of its variance, did not show strong evidence for
publication bias for tomato intake. Figure 4 (lycopene
intake) was consistent with a symmetrical funnel with a
large base and a sharp upper part, showing that there is
no evidence for publication bias.