Serpent (symbolism) The serpent, or snake, is one of the oldest and most widespread mythological symbols. The word is derived from Latin serpens, a crawling animal or snake. Snakes have been associated with some of the oldest rituals known to humankind and represent dual expression of good and evil.
1 Osteoporosis, a condition characterized by reduced bone mineral density and increased bone fragility.  Rickets, a childhood disease characterized by impeded growth and deformity of the long bones. The earliest sign of subclinical vitamin D deficiency is craniotabes, abnormal softening or thinning of the skull.
Nov. 08, 2012. The main symptom of vitamin A deficiency is vision loss and blindness. Vision loss often begins as a problem adjusting to seeing in the dark, or night blindness. People with night blindness do not see well in the dark, but are able to see normally if enough light is present.