Low level radiation probably acts as a beneficial stressor, like exercise or fasting [1]. Although this level is so low it probably does nothing at all.
You also probably don't have to worry about the radiation you get from bananas or plane flights. And it's possible those dumb sounding radioactive water spas might have actually been helpful.
Fukushima is aweful for the nearby region and still a cautionary tale. But it didn't poison the whole world.
[1] http://blogs.discovermagazine.com/crux/2015/04/06/small-radi...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477717/