Vitamin A helps with healthy mucous membranes, skin, vision, tooth and bone growth, health of the immune system. Vitamin A in the plasma or serum is a reflection of the quantities of vitamin A and carotene ingested and absorbed by the intestine. Vitamin A plays an essential role in the function of the retina (adaptation to dim light), is necessary for growth and differentiation of epithelial tissue, and is required for growth of bone, reproduction, and embryonic development. Vitamin E helps to protect the cell walls. Vitamin E contributes to the normal maintenance of biomembranes, the vascular system, and the nervous systems; and provides antioxidant protection for vitamin A. Deficiency of vitamin E in children leads to reversible motor and sensory neuropathies; this problem also has been suspected in adults.