  We examine the extraction of moments of parton distributions from lattice
data, focusing in particular on the chiral extrapolation as a function of the
quark mass. Inclusion of the correct chiral behavior of the spin-averaged
isovector distribution resolves a long-standing discrepancy between the lattice
moments and experiment. We extract the x-dependence of the valence u-d
distribution from the lowest few lattice moments, and discuss the implications
for the quark mass dependence of meson masses lying on the rho Regge
trajectory. The role of chiral symmetry in spin-dependent distributions, and in
particular the lattice axial vector charge, g_A, is also highlighted.
