Vitamins, To use or not to use?

The issue of vitamin use, along with other dietary suplplements gets murkier and murkier. Look at the following headlines from studies of vitamin use
Certain Vitamin Supplements May Increase Lung Cancer Risk, Especially In Smokers
Vitamin Supplement Use May Reduce Effects Of Alzheimer's Disease
Task Force Finds Little Evidence To Support Use Of Vitamin Supplements To Prevent Cancer Or Heart Disease
Widespread Vitamin And Mineral Use Among Cancer Survivors: Benefits Of Such Use Remain Unclear
Vitamins May Decrease Pancreatic Cancer Risk Among Lean People
The one thing in common is that all these studies use memory recall over years. Memory recall over weeks has been shown to be faulty. But the NIH and other grantors keep shovelling out money for inconsequential studies that feed the supplementary diet producers. Too costly a fellowship!