Human digestive process, diet

If nutrients found in food were digested, absorbed, and made available to the human or animal body at the 100% level, the science and practice of nutrition would be indeed simplified. That nutrients vary in their bioavailability has been well established. The chemical nature of the specific form of the nutrient involved, the chemical and physical characteristics of the foods in which nutrients are contained, other constituents of the diet, the nature of the digestive and absorptive processes for the specific nutrients, and the physiological condition of the person consuming the food all may affect bioavailability. However, knowledge of specific individual and interacting factors affecting bioavailability and utilization of nutrients has not yet been fully elucidated and constitutes one of the most active areas of current nutrition research. 

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