Karl,

Just a few ways are world is toxic compared to our paleo-ancesters:
                        Polluted Water, especially chemicals like chlorine and florine
                        Polluted Air
                        Soil Depletion, lack of trace minerals selenium, zinc, vanadium,etc.
                        Pesticides in fruits and vegetables
                        Antibiotics and Hormones in Meat
                        Stress
                        Preservatives and cooking methods

All of the above, can lead to free radical damage.  Even exercise can add to
our free radical load.  An interesting experiment was conducted with a
running club in NYC.  Trained endurance athletes had their blood levels of
T-cells and other immune markers tested prior to and after a marathon.
 Following the marathon, the T-cell level was greatly reduced indicating free
radical damage.  In fact, their readings were as low as most AIDS patients.
 Of course, their levels returned to normal shortly afterwards, but this
shows what even a beneficial activity like exercise can do to our bodies.

Because of our toxic world, which increases our load of free radical damage,
we need to "compensate" by taking supplements.

Ed Campbell, DC,CSCS