Weird dietary requirements notwithstanding, a good multivitamin like Source of life or equivalent from a health food store definitely makes a difference. When I mean multivitamin I mean something that has like 5-10X RDA in certain elements. Forget about drug store brands like Centrex, not enough to keep a hamster going. I seem to feel stronger and more focused. Slept better and generally more energetic during the day.
It's not a hard case to prove that with the modern diet (junk food, lopsided food groups, etc) that the body constantly struggling for the proper nutrients. Even if you eat properly it's a challenge to get all the nutrients you need due to factors like soil depletion - this will help you along. Try some for a week and see how you feel. Start with this, and then get add - on's as you need it. If you're pretty healthy extras above this probably aren't needed. Also easy on the iron - can cause illness if overdone.
Add protein supplements and some raw veggies and it's a pretty decent package for meal replacement, -esp. if you're dieting and restricting calories.
You'll get cool neon pee as an added bonus too
rjp