Specific Heat of Water Solution
From this website:


  Every substance has its own specific heat and each phase has its own distinct value. In fact, the specific heat value of a substance changes from degree to degree, ...


It would mean that a solute in water would change the specific heat from plain water.

My guess is that if the density is greater than water, then the specific heat would be greater (because you are heating the water and the solute). To be certain, you would need to determine it for yourself.