2/3rds of cancers result from chance mutations. As we age our DNA replication fidelity begins to fail, as more errors occur, and when those errors occur in oncogenes and suppressor genes, cancer results. Everything wears out as we age, all of our senses, and yes, even the ability to preserve our genome. Good nutrition and exercise will slow it down, but the inevitable happens.
The one chemical threat that most people ignore is probably the most important and that is air pollution. Humans are vacuum pumps exposing their 2 cell thickness respiratory membrane to about 12 liters of ambient air per minute. If you live in an urban area, there is no escape to the constant bombardment with particulates and chemicals in the air.
Definitely. Air pollution is one of the most insidious and one we can do the least about. It’s not only in inner cities. Beside factories, plants, and even farms, there can be exposure to toxins taken in through our lungs.
I think Americans ignore all ways toxins can get in. Look at every commercial and store, filled with toxic lotions. People will put ANYTHING on their skin, not thinking that it goes right into their bloodstreams. They will eat anything that tastes good. A lot of these things cross the blood brain barrier, which is more like a greedy nightclub bouncer you can pay to get into the club.