Vitamins: An Overview. Vitamins. Essential organic substances (contain carbon) Not synthesized Inadequate synthesis Yield no energy, but facilitate energy-yielding chemical reactions If absent from a diet, it will produce deficiency signs and symptoms. Body Needs Vitamins for Normal.
1 ug of retinol = 1 RAE = 3.3 IU =12 ug beta-carotene = 24 ug of other provitamin A
High amounts of carotenoids in the bloodstream
To become the active hormone, Vitamin D must be
1 mg d--tocopherol = 0.45 IU (synthetic source)
1 mg d--tocopherol = 0.67 IU (natural sources)