Density peaking in tokamak ELMy H-mode plasmas is studied using data from the Joint European Torus (JET). It is shown that the electron density gradient and electron particle flux at mid radius are correlated when these two quantities are normalised to their heat-power-balance counterparts. Therefore the density profiles cannot be considered canonical and particle sources should be taken into account when extrapolating the density profiles to the ITER next step device. The relation between density and temperature gradients at mid radius is predicted in the range of (∇ne/ne)/(∇Te/Te) ≈ 0.15- 0.35 for plasmas with safety factor and collisionality similar to ITER standard discharge.