High resolution 1H-NMR and mass spectrometry provides an approach to investigate complex metabolic effects of diet. Traditional methods to investigate dietary and nutritional components have relied upon isolation and purification of substances with specific biologic activities. However, the very large number of compounds in the diet, the multiple effects of individual compounds, the metabolic changes in the compounds that occur after consumption and the complex interactions of the compounds limit the ability to unravel complex effects such as those due to variation in SAA intake during health, illness and recovery from illness.