Lemonade was called a cure for all poisons even in the time of old Egyptian empire and herbalists from that time definitely knew what they were talking about. They might not have known about vitamin C or the positive effects on the body, but they have certainly been familiar with the fact that rubbing drops of lemon oil over one's wounds would help it heal better and also that the digestive system worked much more efficiently if they drink lemonade after a big meal. However, that was not all: they knew about the effects of lemonade on immune system.
Lemonade will wake you up when you are tired, help with the healing processes when you are injured and bolster your immune and digestive systems when you are sick - no reason to avoid this heaven-sent beverage.