White light has all the different light colors in almost equal proportions. When white light strikes an object, most colors of light are absorbed and a few are reflected. The color of an object is determined by the color of light it reflects. It is important that a light source emits light with all the colors of light in it.
If light from a source does not have a particular color of light, objects of that color cannot in their natural colors. This is why sodium lights are so bad at reproducing colors. Sodium light is what is called a narrow spectrum light. It is made of primarily yellow light. When an object of a color other than yellow is placed under sodium lights different shades of yellow are reflected.
Additionally, almost every object has a sickly hue. LEDs produce natural colors as the light is well balanced and contains an ideal spread of all light colors.