Some of the functions of vitamin A are in the body's vision, mucous membranes, cell division, skin maintenance, sperm production, egg development, growth, bone development and cancer prevention. Symptoms indicate a deficiency of vitamin A in the body include poor vision, night blindness, "bumps" on skin, lower disease resistance, stunted growth, pregnancy problems, acne, and xerosis. Preformed vitamin A is found mainly in animal meats. Beta carotene is composed of two vitamin A molecules and is found in green or orange vegetables, and fruits. These include carrots, squash, spinach, apricots, etc. The RDA for vitamin A is 3000 I.U. per day. A supplemental dose could range from 5000 to 10,000 I.U. A toxic dose may occur at 25,000 to 50,000 I.U. The body will convert beta carotene to vitamin A if the thyroid is functioning properly and the patient does not have diabetes. These two conditions may lead to a high serum beta carotene and low serum vitamin A.