Although research has highlighted the importance of zinc for the immune system, because the mineral has many complex roles in the body it is not understood in any detail how it helps fight off infection.

BBC: Zinc 'keeps immune system in check'

Its interlocking cogs of power and influence -- geopolitical, regional, governmental, tribal, mineral, criminal, spiritual, clan and family -- are fiendishly complex.

CNN: Mali's conflict turns musicians into military