Go ahead and take those vitamins. There will be no harm in taking them,
especially when you work out...when you sweat, you automatically also lose some of your nutrients in your body.
So, eating LOTS of yummy greens, beans-(protein) brown rice...and different kinds of fruits, should do you good.
If you are a vegetarian (because we Do Not need flesh from another sentinent), make also sure to get an extra B-complex.
So, a general multivitamin-mineral, a B-complex supplement and maybe some extra vitamin C. (Taken together with your multi/and -or food.)
See how you feel, okay