I do not fully agree with your point, because it is not black or white, it is a spectrum.
So, short of living next to a leaking power station or contaminated waters, the food you eat is the most intimate way you make contact with your environment.
Do not forget that your body fights free radicals and oxidative stress. If you give it the proper nutrition it needs to repair itself and eliminate waste then you are statistically in a very good position.<p>Also, about Genes: you may have genes that are more sensitive to certain chronic diseases, but it is your environment that activates those genes. 
Example, if you are at risk of diabetes, but eat very well, you may never get diabetes.