Everyone has it to some degree. The problem is western diets high in simple carbs feed it and all the drugs we take, like antibiotics especially, kill off the good flaura in our gut. Kill the good, feed the bad and over time you have problems.
The sad part is the medical community by and large doesnt spend any time looking at it as a problem until its reached critical mass.
I don't have it to a really cronic stage, Some symptoms but not all The doctor sau it can be debilitating in severe cases but in mine I appear very healthy and fit.