We study two families of integral functionals indexed by a real number p>0. One family is defined for 1-dimensional curves in R3 and the other one
is defined for m-dimensional manifolds in Rn. These functionals are
described as integrals of appropriate integrands (strongly related to the
Menger curvature) raised to power p. Given p>m(m+1) we prove that
C1,α regularity of the set (a curve or a manifold), with α>α0=1−pm(m+1) implies finiteness of both curvature functionals
(m=1 in the case of curves). We also show that α0 is optimal by
constructing examples of C1,α0 functions with graphs of infinite
integral curvature