Peristalsis is a wave like muscular contraction that squeezes food through the digestive tract and intestines to be digested. Things like Mold Illness, Lyme Disease and Parasite Infections can affect peristalsis. Hypothyroidism also affects peristalsis and motility. Pathogens slow, interrupt, and stagnate digestion by blocking how your body processes food, slowing down the action of peristalsis.