  In this work we study the phenomenological consequences of the existence of
long-range forces coupled to lepton flavour numbers in solar neutrino
oscillations. We study electronic forces mediated by scalar, vector or tensor
neutral bosons and analyze their effect on the propagation of solar neutrinos
as a function of the force strength and range. Under the assumption of one mass
scale dominance, we perform a global analysis of solar and KamLAND neutrino
data which depends on the two standard oscillation parameters, \Delta m^2_{21}
and \tan^2\theta_{12}, the force coupling constant, its range and, for the case
of scalar-mediated interactions, on the neutrino mass scale as well. We find
that, generically, the inclusion of the new interaction does not lead to a very
statistically significant improvement on the description of the data in the
most favored MSW LMA (or LMA-I) region. It does, however, substantially improve
the fit in the high-\Delta m^2 LMA (or LMA-II) region which can be allowed for
vector and scalar lepto-forces (in this last case if neutrinos are very
hierarchical) at 2.5\sigma. Conversely, the analysis allows us to place
stringent constraints on the strength versus range of the leptonic interaction.
