Vitamins--conventional uses and new insights.

There are 13 nutrients classified as vitamins: 4 'fat-soluble' and 9 'water-soluble'. All are essential to maintain healthy homeostasis and metabolic function. Preterm infants are born with low levels and reduced stores of fat-soluble vitamins. Active placental transfer of water-soluble vitamins ensures high levels at birth, but as they are not stored, levels fall rapidly. All VLBW and ELBW infants require vitamins to be provided soon after birth. Quantifying exact requirements of each vitamin which will meet the needs for all infants is difficult due to a limited evidence base. However, timely prescription of vitamin supplements and awareness of situations where delivery or uptake might be compromised will help to ensure that these vulnerable patients do not suffer from vitamin deficiencies. Multivitamin preparations are available for parenteral and enteral use. Vitamins A, C and E have important functions as antioxidants. Further research is required to understand optimal doses and routes of administration for initial and ongoing nutritional support.