Recently i got my blood platelets tested, these were below normal 120000 per micro-liter, i want to know its most probable causes and its cure & diet?

Follow it: Diet isn't the key to this or the vast majority of other health problems. Anyone who tells you otherwise is misleading you. Lab reference ranges are set so that a few percent of healthies fall outside on either end. Nobody worries about serious disease until platelets drop below 90,000 or so. You're in no danger. Be happy for good health. Go play contact sports and don't worry about bleeding.