Synthesis of long-chain polyunsaturated fatty acids in preterm newborns fed formula with long-chain polyunsaturated fatty acids.
BACKGROUND
Docosahexaenoic acid (DHA) and arachidonic acid (AA) are long-chain polyunsaturated fatty acids (LCPs) that play pivotal roles in growth and neurodevelopment.


OBJECTIVE
We aimed to quantify the synthesis of LCPs in preterm infants fed infant formula containing LCPs.


METHODS
Twenty-two preterm infants were randomly assigned to either the no-LCP group (fed formula without LCPs; n = 11) or the LCP group (fed formula with LCPs; n = 11). Dietary LCPs had higher (13)C content than did the endogenously synthesized LCPs, which were derived from linoleic and alpha-linolenic acids. The (13)C content of major selected plasma fatty acids was measured by using gas chromatography-isotope ratio mass spectrometry at birth and at age 1, 3, and 7 mo. Absolute LCP synthesis and the percentage of LCP synthesis relative to dietary intake were calculated.


RESULTS
Percentage AA synthesis was 67.2 +/- 7.8%, 35.9 +/- 9.8%, and 29.0 +/- 10.3%, and that of DHA was 41.7 +/- 14.9%, 10.5 +/- 8.1%, and 7.4 +/- 6.2% at 1, 3, and 7 mo old, respectively. Absolute AA synthesis was 26.7 +/- 4.2, 14.4 +/- 3.9, and 11.6 +/- 4.1 mg x kg(-1) x d(-1) and that of DHA was 12.6 +/- 4.5, 3.2 +/- 2.5, and 2.3 +/- 1.9 mg x kg(-1) . d(-1) at 1, 3, and 7 mo old, respectively. AA and DHA synthesis decreased significantly (P < 0.01) with time, and AA synthesis was significantly (P < 0.01) greater than DHA synthesis.


CONCLUSIONS
By this novel approach, we measured endogenous LCP synthesis in infants receiving dietary LCPs over long periods. By age 7 mo, LCP synthesis was dramatically lower in preterm infants fed LCPs.
Carnielli
Virgilio P
VP
Division of Neonatology, Institute of Maternal-Infantile Sciences, Polytechnic University of Marche, Ancona, Italy. lab2@pediatria.unipd.it
Simonato
Manuela
M
Verlato
Giovanna
G
Luijendijk
Ingrid
I
De Curtis
Mario
M
Sauer
Pieter Jj
PJ
Cogo
Paola E
PE
D016718:Arachidonic Acid / Q000096:biosynthesis; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D004281:Docosahexaenoic Acids / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D041943:Infant Formula; D007231:Infant, Newborn; D007234:Infant, Premature; D010743:Phospholipids / Q000097:blood
D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid