Red, yellow green Bell peppers originate from the same species of plant and achieve their different colors naturally. Different colored pepper indicate unique array of nutritional benefits, green peppers are rich in chlorophyll, yellow peppers are excellent source of lutein and zeaxanthin carotenoids, orange peppers are rich in alpha, beta, and gamma-carotene, red peppers have more lycopene and astaxanthin.

Source: http://www.gud2eat.com