Beta-carotene is a member of the carotenoids, which are highly pigmented (red, orange, yellow), fat-soluble compounds naturally present in many fruits, grains, oils, and vegetables. Beta-carotene is considered a provitamin because it can be converted to active vitamin A, which in turn, serves several biological functions including involvement in the synthesis of certain glycoproteins. Furthermore, beta-carotene is converted to retinol which is essential for vision and involved in processes involving growth and cell differentiation. LOW levels of beta-carotene may indicate vitamin A deficiency, which is associated with abnormal bone development, disorders of the reproductive system, xerophthalmia, and ultimately death. Low levels may also be seen in liver disease, and in conditions in which intestinal absorption is inhibited. EXTEMELY HIGH levels cause hypercarotenemia, and this can be observed in hypothyroidism, diabetes, high dietary intake of carotenes, and protoporphyria. Hypercarotenemia may also lead to carotenodermia, in which the skin becomes yellow.