Take a look at the jobs that people with advanced degrees in economics take. They are more likely to become analysts for government agencies or in the back rooms of financial institutions than to take managerial positions. Economics is an academic field, not a managerial one. An economics degree does not cover all the functional areas that an MBA does. Most MBA programs, however, do require one or more basic economics courses.
Whether economics is the right choice depends on what you want to do with your career. You can talk to the placement group in the economics department of your local university or even check out the job openings advertised in economics journals rather than business magazines.
Good luck,
Tani Wolff