Sperm Count - what sort of food or viatamins can i take to improve my sperm count?

what sort of food should one eat to increase one's sperm count - are there any viatamins or food that i can eat to make me more potent - i am 42 and i am trying for a baby with my wife, been to the dr and my sperm count is ok, but i feel there must be something i can do to enhance my chances