"Patricia Heil" wrote in message
...

An excess of any nutrient causes problems. This
include water soluble vitamins like Bs and C. People
who take more than the RDA are putting themselves
at risk.

Especially since it's neither hard nor expensive to have some
micro-nutriments levels in blood tested *before* taking a supplement. The
cost of the test is very low compared to the cost of an unnecessary
supplement. Things that are both very easy to test and harmful to overdose :
potassium, calcium, iron...