White and brown rice are not different species. The difference is that brown rice has two distinctive parts that white rice lacks: the bran, the germ.
When you get rid of the bran and germ in rice, what you’re really removing, nutrition-wise is as follows: you’re removing:
Calcium, which is important for teeth and bone health
Fat, which consists of healthy unsaturated fats that are important for cardiovascular health
Phosphorus, which collaborates with calcium to form strong bones and teeth
Vitamins B1 (thiamine) and B3 (niacin), which helps keep the nervous system functioning properly
Protein, which helps build muscle and is essential for growth and development
Magnesium, which is important for proper neurological function among many other benefits.
Brown rice has more soluble and insoluble fibre and protein than white rice. While most of the calories in white and brown rice come from carbohydrates, white rice has a higher glycemic index than brown rice.