Do We Really Need To Wash Rice Before Cooking?

This is not a straightforward questions, so I would answer YES and NO. You ask why? Often, we only do things because that is the way it has always been done and do not bother to ask, “why?” Such is the case with the issue of rinsing of rice in water before we cook. Some people even soak or parboil the rice and change the water after some minutes of cooking – like we recommended you do with beans if you don’t want it to make you fart after eating
.
Rinsing rice has been done for ages to rid the grains of surface starches, prevents clumping, and yields a clean, fresh taste. If you rinse rice very well, the cooked rice will have a reduced likelihood of clumping together because you have removed some of the total starch present (surface starch).
Some types of rice from some parts of the world are processed with talc -a mineral made up of hydrated magnesium silicate in order to give it a whiter and cleaner appearance. These types of rice need a rinse to remove this talc. Sometimes when rice has been packed and stored for long, you see some kind of dust on their surface when you take them out, washing will get rid of dusts like these and sometimes few weevils in the rice.
To explain my NO, which also answers “if you wash nutrients away when you wash rice”…
Starch is Carbohydrate so when you wash it away, you wash away nutrients but there is more of that inside the rice. You may not want to worry much about this. However, to make milled white rice healthier and more nutritious in countries like the United States, it is required that processors enrich it with vitamins and other nutrients.
These fortifications appear as a dusty layer on the individual grains. If you want to also preserve those nutrients, washing is not for you – it is NO-NO. But if you don’t need this nutrients, probably because you are eating your rice with some rich vegetable sauce and other nutritious foods, you can wash it off.
Conclusively, rinsing rice prior to cooking or not depends on what you want out of your rice but I do it because  I cannot distinguish between a dust that comes as a result of fortification and that which is there as a result of dirt.