It is well-known that brown rice is a healthier alternative to white. The difference between the two is that white rice is devoid of bran, which is full of vitamins, minerals and antioxidants. Like brown rice, black rice has similar nutrient levels and higher amounts of antioxidants. It is also a source of fiber and minerals, including iron. A 100 gram serving of black rice has 8.5 grams of protein, 3.5 milligrams of iron and 4.9 grams of fiber. Compared to white, brown and red rices, black rice has the highest amount of protein and double the fiber of brown rice.