Which natural food or vitamin works like adderall or ritalin (methylphenidate)?

Caffeine & xanthines: Caffeine & xanthines are naturally occuring stimulants & widely available in many products. They are weaker than Adderall or Ritalin (methylphenidate) and shorter acting but have similar effects overall. There is no evidence that any vitamins have stimulant activity. Stimulants are among the best-studied and safest medications we have, when used appropriate. "natural" doesn't mean safe: hemlock is natural.