The long-term objectives of this research are to improve the definition of optimal human SAA intake. This will include defining Dietary Reference Intakes (DRI), estimated average requirement (EAR), and the upper limit (UL) of intake by improving the understanding of the physiologic and pathologic responses to variatiation in SAA intake. Using high-resolution 1H-NMR, we plan on developing comprehensive metabolic profiles that can indicate when SAA intake is inadequate.