Q. If sugar is not good for the brain, why are people given a glass of orange juice when they have low blood sugar?

A. Blood sugar highs and lows are not good for the brain. If glucose gets too low in the brain it cannot function appropriately. If there is a real low-glucose episode, the person often is given orange juice because it is high in glucose and can help to rebalance the blood sugar level quickly. Ordinarily drinking juice can cause its own blood sugar high.