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.
Symptoms. An early symptom of vitamin A deficiency is night blindness, which is caused by a disorder of the retina. Soon thereafter, the whites (conjunctiva) and corneas of the eyes may become dry and thickâa condition called xerophthalmia.isorders that impair the intestineâs absorption of fats can reduce the absorption of vitamin A and increase the risk of vitamin A deficiency. These disorders include chronic diarrhea, celiac disease, cystic fibrosis, certain pancreatic disorders, and blockage of the bile ducts.