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A randomized trial of long-chain polyunsaturated fatty acid supplementation in infants with phenylketonuria
Carlo Agostoni1, Ann Harvie, Daphne L McCulloch
1Department of Pediatrics, University of Milan Medical School, Milan, Italy. carlo.agostoni@unimi.it
Insights
Phenylketonuria (PKU) infants supplemented with long-chain polyunsaturated fatty acids (LC-PUFA) maintained docosahexaenoic acid (DHA) levels. This dietary intervention prevented DHA decline, potentially supporting visual system maturation in infants with PKU.
Area of Science:
- Biochemistry
- Pediatrics
- Nutrition Science
Background:
- Classical phenylketonuria (PKU) requires a strict phenylalanine-free diet.
- Infant formulas for PKU typically lack essential long-chain polyunsaturated fatty acids (LC-PUFA).
- Docosahexaenoic acid (DHA) is crucial for infant development, particularly visual maturation.
Purpose of the Study:
- To assess the impact of a phenylalanine-free infant formula supplemented with LC-PUFA on biochemical and physiological outcomes in infants with PKU.
- To determine if LC-PUFA supplementation prevents DHA decline in PKU infants.
- To explore the relationship between DHA status and visual system maturation in PKU.
Main Methods:
- Prospective, double-blind, randomized study involving 42 infants with classical PKU.
- Comparison between a group receiving LC-PUFA supplemented formula and a control group.
- Measurement of DHA levels in erythrocyte membrane phospholipids over 20 weeks.
Main Results:
- Infants receiving LC-PUFA supplemented formula showed a significantly smaller decrease in median DHA levels (15-22%) compared to the control group (61-64%).
- Dietary LC-PUFA supplementation effectively prevented the decline in DHA levels observed in the control group (p<0.001).
- The study highlights the importance of LC-PUFA in PKU infant nutrition.
Conclusions:
- Dietary supplementation with LC-PUFA in phenylalanine-free formula is effective in maintaining DHA status in infants with PKU.
- Adequate DHA levels, independent of diet, may be essential for visual system maturation in infants with PKU.
- This finding supports the inclusion of LC-PUFA in specialized infant formulas for PKU management.
Abstract:
Forty-two infants (20 males, 22 females) with classical phenylketonuria (PKU) entered a prospective, double-blind, randomized study to investigate the effects on biochemical and physiological outcomes of a phenylalanine-free infant formula containing a fat blend supplemented with the long-chain polyunsaturated fatty acids (LC-PUFA), docosahexaenoic acid (DHA, C22:6 n-3), and arachidonic acid (AA, C20:4 n-6). Between entry and 20 weeks (entry and 1y) of age, median DHA levels in erythrocyte membrane phospholipids decreased by 15% (22%) in the LC-PUFA supplemented group (n=21) and by 61% (64%) in the control group (p<0.001; n=18). A dietary supply of LC-PUFA in infants with PKU prevents the decline in DHA levels associated with a diet supplying minimal sources of LC-PUFA. DHA status in turn, independent of diet, may influence the maturation of the visual system in infants with PKU.
