Roasted peppers have a sweet taste to them and are a great addition to fajitas. Yellow peppers contain Vitamin A, C, and B6. They are also a source of niacin, magnesium, potassium, folate, and manganese. Red peppers contain Vitamin A, C, B6, K, and E. They are a source of thiamin, riboflavin, niacin, potassium, folate, and manganese. Both of these pepper varieties are a source of fiber too.