Effect of fish oil supplementation on fatty acid status, coordination, and fine motor skills in children with phenylketonuria

Omega-3 LC-PUFA supply and neurological outcomes in children with phenylketonuria (PKU)

Children with phenylketonuria (PKU) follow a diet with very low intakes of natural protein, which is devoid of food sources of the omega-3 docosahexaenoic acid (DHA). A resulting DHA depletion has been demonstrated in PKU children and may account for detectable subtle neurological deficits that are not explained by variation in plasma phenylalanine concentrations. We supplemented 36 children with PKU ages 1 to 11 years for 3 months with encapsulated fish oil providing a daily dose of 15 mg DHA/kg body weight. DHA supplementation resulted in significantly faster visual evoked potential latencies, indicating more rapid central nervous system information processing. In addition, DHA significantly improved outcomes in a test of motor function and coordination. No changes over time were seen in age-matched healthy controls. Because the PKU children had a good supply of the omega-3 precursor alpha-linolenic acid, these observations lead us to conclude that endogenous conversion of alpha-linolenic acid is not sufficient to provide adequate amounts of DHA that support optimal function, and hence DHA appears to be a conditional essential substrate for children with PKU. Because early treated PKU children are healthy, with normal fatty acid turnover, these data may indicate a need to supply some DHA to children in general. Further studies are ongoing aiming at establishing quantitative DHA requirements in children.

The roles of long-chain polyunsaturated fatty acids in pregnancy, lactation and infancy: review of current knowledge and consensus recommendations

This paper reviews current knowledge on the role of the long-chain polyunsaturated fatty acids (LC-PUFA), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (AA, 20:4n-6), in maternal and term infant nutrition as well as infant development. Consensus recommendations and practice guidelines for health-care providers supported by the World Association of Perinatal Medicine, the Early Nutrition Academy, and the Child Health Foundation are provided. The fetus and neonate should receive LC-PUFA in amounts sufficient to support optimal visual and cognitive development. Moreover, the consumption of oils rich in n-3 LC-PUFA during pregnancy reduces the risk for early premature birth. Pregnant and lactating women should aim to achieve an average daily intake of at least 200 mg DHA. For healthy term infants, we recommend and fully endorse breastfeeding, which supplies preformed LC-PUFA, as the preferred method of feeding. When breastfeeding is not possible, we recommend use of an infant formula providing DHA at levels between 0.2 and 0.5 weight percent of total fat, and with the minimum amount of AA equivalent to the contents of DHA. Dietary LC-PUFA supply should continue after the first six months of life, but currently there is not sufficient information for quantitative recommendations.

Correlation between changes in blood fatty acid composition and visual sustained attention performance in children with inattention: effect of dietary n-3 fatty acids containing phospholipids

BACKGROUND

Increasing evidence supports n-3 fatty acid (FA) supplementation for patients with psychiatric disorders, such as attention deficit hyperactivity disorder. However, the exact metabolic fate of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on different glyceride carriers remains unclear.

OBJECTIVE

We investigated whether conjugation of EPA and DHA to phospholipid (PL-n-3) or to triacylglycerol (fish oil; FO) affects their incorporation in blood compartments and influences executive functioning.

DESIGN

Children aged 8-13 y with impaired visual sustained attention performance received placebo, 250 mg/d EPA + DHA esterified to PL-n-3 (300 mg/d phosphatidylserine), or FO for 3 mo in a randomized double-blind manner. Main outcome measures included plasma and erythrocyte FA profile and continuous performance test results (Test of Variables of Attention; TOVA).

RESULTS

Sixty of the 83 children enrolled completed the interventions (n = 18-21 per group). There was an enrichment of EPA (1.5-2.2-fold), docosapentaenoic acid (DPA; 1.2-fold), and DHA (1.3-fold) in the PL fraction in the plasma of FO- and PL-n-3-fed children. In erythrocytes, only PL-n-3 resulted in a significant reduction (approximately 30%) of very-long-chain saturated FAs (C20-24) and in an increase (1.2- and 2.2-fold, respectively) in linoleic acid and DPA. Total TOVA scores increased in the PL-n-3 (mean +/- SD: 3.35 +/- 1.86) and FO (1.72 +/- 1.67) groups but not in the placebo group (-0.42 +/- 2.51) (PL-n-3 > FO > placebo; P < 0.001). A significant correlation between the alterations in FAs and increased TOVA scores mainly occurred in the PL-n-3 group.

CONCLUSION

Consumption of EPA+DHA esterified to different carriers had different effects on the incorporation of these FAs in blood fractions and on the visual sustained attention performance in children. This trial was registered at clinicaltrials.gov as NCT00382616.

Phenylketonuria: questioning the gospel

Phenylketonuria (PKU) was first described over 70 years ago, treatment was developed 50 years ago and universal newborn PKU screening was introduced 40 years ago. Phenylalanine-restricted dietary treatment has prevented mental retardation in thousands of individuals worldwide. We acknowledge, however, that there is still much to learn in the field. The incidence of mental retardation in untreated PKU is likely to be considerably less than the original estimates. Since dietary control is suboptimal in late childhood, adolescence and adulthood, alternative methods of treatment are being explored. These include large neutral amino acids, phenylalanine ammonia lyase, tetrahydrobiopterin and gene replacement. Evidence has surfaced that the semisynthetic, low-protein diet used to treat PKU may be deficient in certain important nutrients. Maternal PKU treatment may be successful even if initiated as late as 8-10 weeks into pregnancy. A plea is made for the immediate establishment of adult treatment centers for PKU (and other inherited metabolic diseases) for long-term treatment, follow-up and research.

Dietary long-chain polyunsaturated fatty acid supplementation in infants with phenylketonuria: a randomized controlled trial

BACKGROUND

Pre- and postnatal tissue accretion of long-chain polyunsaturated fatty acids (LCPUFA) has been related to visual and cognitive development in healthy children in several studies. Children with phenylketonuria (PKU) consume diets with very low contents of preformed LCPUFA. We studied prospectively the LCPUFA status in infants with PKU without or with LCPUFA supplementation during the first year of life.

SUBJECTS AND METHODS

Infants with PKU were enrolled at diagnosis (<4 weeks of age) and randomized double blind to phenylalanine-free amino acid supplements without LCPUFA (n = 11) or with both arachidonic (AA, 0.46 wt%) and docosahexaenoic acids (DHA, 0.27 wt%) (n = 10). At enrolment and again at 1, 2, 3, 4, 6, 9 and 12 months, plasma phospholipid fatty acids were measured and dietary intakes were calculated from dietary protocols.

RESULTS

Unsupplemented patients showed a marked LCPUFA depletion to levels clearly below those observed in healthy breast-fed infants. In contrast, supplemented infants had stable and higher LCPUFA levels than unsupplemented infants, reaching significant differences for AA values at 3, 4 and 6 months, and for DHA values at 1, 3, 4, 6, 9 and 12 months. Plasma phospholipid levels correlated closely with estimated dietary intakes of preformed LCPUFA.

CONCLUSION

Low LCPUFA intakes with PKU diets induce marked depletion of AA and particularly of DHA in the first year of life. Thus endogenous synthesis of LCPUFA from precursors supplied by diet seems unable to compensate for low LCPUFA intakes. LCPUFA supplementation of PKU diets during the first year of life effectively enhances LCPUFA status to levels comparable to those of healthy breast-fed infants.