Vitamins & Supplements: The Good, The Bad and the Bogus Toxic Nutritional Supplements Reference Citation W Short Cliff Notes This is complicated and obscured by the fact that over one third of the vitamins and supplements on the market today are "bogus" and do not contain what their labels say they do ( 5 PDF ,   5a , 5b , 5c , 5d , 5e ). But as a report from 1999 shows (5 pdf page 60 ) this has been known for over a decade and I doubt that it is about to change any time soon. There was also a problem with Omega 3 fish oil  BEFORE the Gulf Oil Disaster { 5e } And some of the plastic bottles {such as used with SOME Flax Seed Oil} that leach toxic neuro chemicals like BPA {and or other chemicals} into the oil. So in "my opinion", only buy food oil , Olive, Hemp, Flax Seed in GLASS. Reference Citation Follows: 5a : Vitamins often do not contain the nutrients they claim By Dominika Osmols.EMax Health Jun 17 2011 Reference 5a of references