Vitamin D is necessary for proper bone and teeth formation, and for the healthy functioning of the thyroid gland. It assists in the assimilation of calcium, phosphorus and other minerals from the digestive tract. This vitamin is found in the rays of the Sun, fish, milk and eggs, butter and sprouted seeds. A deficiency can cause gross deformation of bones and severe tooth decay.
The recommended daily allowance of this vitamin for both adults and children is 400 to 500 international units. Therapeutically, up to 4000 to 5000 units a day for adults and half of this for children, is safe dose, if taken for not longer than one month. It is beneficial in the treatment of muscular fatigue, constipation and nervousness. It can be toxic if taken in excessive doses, especially for children. Signs of toxicity are unusual thirst, sore eyes, itching skin, vomiting and diarrhoea, urinary urgency, abdominal calcium deposits in the blood vessels walls, liver and kidneys and stomach.