Distortion of body proportions can occur when you shoot from an extreme point of view - in this case, from high above the subject. For most portraits, you should position the camera at the subject's eye level.

A high camera angle creates the impression of diminished stature, as if the viewer is towering over the subject. On the flip side, shooting from a very low angle can make subjects appear haughty because they seem to be looking down their noses at the viewer.
In addition, a high or low camera angle may distort your subject's physical proportions, as illustrated above.

Directing your subject's eyes to a position slightly above the camera can help reduce red-eye ; but a straight-ahead gaze creates a stronger sense of intimacy. Just because your camera is positioned at eye level doesn't mean that you always need to have your subject looking straight into the lens, though.
A straight-ahead viewpoint creates a greater sense of intimacy because the subject appears to be looking the viewer in the eye.