Cause of early death

I read in the newspapers that humans across the world are nowadays experiencing shorter and shorter life spans. The reasons are many but the most striking one offered  was the simple explanation that since we are eating food grains which have been forced to grow to maturity in a short period our life span is also reduced.  That is to say that if in the old days it took 4 months for grain to grow from being planted as a seed until harvest this same grain through modern technology is now being made to mature and ripen within 2 months. I wasn't convinced about this being the reason but maybe there is some other reason for our life span getting reduced. Could it be because of the chemical fertilisers that are being used.

Panchapakesan, Coimbatore

The above referenced video can be seen at: