Anastasia Stephens on her article on dailymail.com.uk, reports that the bell peppers contain 3 times more vitamin C levels more that citrus fruits according to Bridget Benelam of British Nutrition Foundation.
A cup of chopped red bell pepper will have 100% - 150% of the daily recommended intake of vit. C, 80% of vit. A. Lycopene, beta-carotene, zeaxanthin, folic acid, potassium and iron can also be found.
But there are ways that should be followed to get the most of the nutrition out of these pepper, on the full article(link below).
Link: Why the pepper is worth its salt (in Vitamin C) | Mail