Yes, parasites can have an effect on your nutrient levels. Some worse than others, and not just when they eat your food. They cause malabsorption in the intestines, and also when they disrupt your vital organs from functioning properly. Such as the case with Vit-D, which is synthesized within the body, it makes sense that if parasites are impeeding normal functioning, then it could make those levels low also. I have nothing to back that up of course, just logic. :)
I have read several cases on this site where posters have actually cured MS, or had their diagnosis reversed by cleansing. That would be wonderful if you were so lucky! I agree with Lorica Lady, you should keep cleansing.
I also remember some relationship between worms and MS, but to be honest, it was a while back and I have not saved the data. Did you get any worms out while cleansing? Also, which I think is crazy, they are treating MS with parasitic worms.