The author makes a good point in that what is perfectly safe for one person may be deadly to another. Off the top of my head, one example of this is how some pe

The author makes a good point in that what is perfectly safe for one person may be deadly to another. Off the top of my head, one example of this is how some people are congenital 'super-absorbers' of iron. These people can develop iron overload from ingesting levels of iron that have no effect on ordinary people. http://en.wikipedia.org/wiki/Iron_overload http://en.wikipedia.org/wiki/Iron_overload