  Theories which include neutrinos in large extra dimensions can be constrained
by nuclear beta decay experiments. We examine universality of beta decay
strengths of Fermi transitions. From this we find that the extra dimensional
Yukawa coupling for a higher dimensional scale of 10 TeV, and two extra
dimensions can be constrained to y < 1. Kinematic implications are also
discussed. In particular, an extra dimensional scenario will produce a tritium
decay endpoint spectrum with a different shape than that for just one massive
state.
