Natural fibers will have less microplastics than synthetics like polyester (literally plastic fibers). Eating a predominantly plant based diet (actual fruit and veg, not imitation meat) with little to no processed foods from the center aisles will mean ingesting fewer microplastics. Switching from bottled water to filtered will reduce the amount of microplastics you drink. Stop using tupperwares and saran wrap immediately and instead use glass containers whenever possible.
There's no way to get rid of them completely, but there are ways to mitigate your exposure.