The role of nucleotides in human nutrition

Dietary NT are reported to have significant effects upon lymphoid, intestinal and hepatic tissues, and lipid metabolism (Table 3). The mechanism remains unknown, and the nutritional role of NT remains controversial. However, maintenance of the endogenous NT supply via de novo synthesis and salvage is metabolically costly. Preformed NT supplied by the diet may contribute to tissue NT pools and thus optimize the metabolic function of rapidly dividing tissues such as those of the gastrointestinal and immune systems. An exogenous source of NT may be particularly important for individuals whose dietary intake of NT is low and/or whose tissue needs are increased, for example, rapidly growing infants fed most cow's milk-based formulas and individuals with disease related immunosuppression, intestinal, or liver injury. Under these conditions, dietary NTs may play a role as conditionally essential nutrients. In addition to serving as nucleic acid precursors, NTs and their related metabolic products are potent inter- and intracellular biological mediators. Certain effects of dietary NT may relate to one or more of these important functions. Area for future study include: 1. The absorption and metabolism of nucleic acids, NTs, NSs, bases, and related metabolic products in humans, and the effects of age and disease upon these activities. 2. Dietary NT effects upon gut-associated lymphoid tissues. 3. The content of nucleic acid, NTs, NSs, bases, and their related metabolic products in human milk. 4. The relative contribution of nucleic acid, NTs, NSs, and free bases to observed biologic effects, and the effects of individually administered purine and pyrimidine compounds.