Role of nucleotides in intestinal development and repair: implications for infant nutrition.

Dietary sources of nucleotides may be conditionally essential nutrients. Rapidly growing tissues such as the intestinal epithelium and lymphoid cells lack significant capacity for de novo synthesis of nucleotides and require exogenous sources of purine and pyrimidine bases. Dietary purines are not significantly incorporated into hepatic nucleic acids, but pyrimidines are. Both are taken up by intestinal cells with excess purines converted to uric acid. Nucleotides are important for normal development, maturation and repair of the gastrointestinal tract. Human milk is the best source of nucleotides for young infants because cow's milk is lacking in nucleotide content. It is likely that infant formulas should have sources of nucleotides added to more closely duplicate human milk and provide these substrates for maximal intestinal development and repair.