Lower n-3 long-chain polyunsaturated fatty acid values in patients with phenylketonuria: A systematic review and meta-analysis

Department of Pediatrics, University of Pécs, Hungary. Electronic address: .
Nutrition research (Impact Factor: 2.47). 07/2013; 33(7):513-20. DOI: 10.1016/j.nutres.2013.05.003
Source: PubMed


The mainstream of phenylketonuria (PKU) management is lifelong restriction of protein intake; however, this dietary restriction may be accompanied by insufficient dietary intake of long-chain polyunsaturated fatty acids (LCPUFA). The objective of this review was to assess whether significant depletion of LCPUFA can be detected in PKU patients on low-protein diet and whether LCPUFA supplementation is an effective way to increase the availability of LCPUFA in PKU patients. The method included structured search strategy on Ovid MEDLINE, Scopus, LILACS, and the Cochrane Library CENTRAL databases, with formal inclusion/exclusion criteria, data extraction procedure, and meta-analysis. We evaluated 9 case-control studies and 6 randomized controlled trials, dated from the inception of the databases to 2012. The meta-analysis of the case-control studies showed significantly lower values of both eicosapentaenoic acid and docosahexaenoic acid (DHA) in all biomarkers investigated and that of arachidonic acid in total plasma lipids in PKU patients as compared with healthy controls. There were sufficient data to demonstrate that dietary DHA supplementation of patients with PKU significantly increases the contribution of DHA to total plasma lipids. In summary, suboptimal LCPUFA status, especially that of n-3 LCPUFA, can be detected in PKU patients. Supplementing DHA to the diet of PKU patients may improve their LCPUFA status; however, further research is needed to determine the optimal supplementation dosage and to establish beneficial functional outcomes.

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    • "Suboptimal DHA status is evident despite more than adequate levels of the precursor ALA. EPA levels were elevated, which differs from previous studies (Lohner et al. 2013), consistent with the findings of Infante and Huszagh (2001), suggesting that PHE metabolites may inhibit later stages in the pathway for DHA synthesis. This has relevance to current nutritional guidelines (Singh et al. 2014) which suggest that supplementation with the precursor ALA or with preformed DHA is appropriate in patients with low levels of n3LCPUFA. "
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    ABSTRACT: Background: Omega-3 long-chain polyunsaturated fatty acids (n3LCPUFA) levels are reduced in phenylketonuria (PKU). Recent care guidelines recommend essential fatty acid status is monitored in patients with PKU but access to such testing is limited. We hypothesized that information obtained on diet history would identify PKU adults with suboptimal levels of n3LCPUFA. Methods: A 12-month single site prospective study was completed including 35 adults (age 18-46) attending a clinic for adults with inborn errors of metabolism. Levels of n3LCPUFA were correlated with estimated intake using a published food frequency questionnaire. n3LCPUFA levels were tested at a commercial laboratory and values > one SD below the laboratory mean value were considered suboptimal. Results: Mean levels of docosahexaenoic acid (DHA) were lower and levels of eicosapentaenoic acid (EPA) and alpha-linoleic acid (ALA) higher in subjects with PKU than in laboratory controls. n3LCPUFA levels correlated with estimated intake (p <0.002). Diet history had a positive predictive value of 93% and negative predictive value of 90% to identify subjects with suboptimal n3LCPUFA levels. Conclusions: Diet history is sufficient to predict adult subjects who may have low DHA levels and can be used to target testing or supplementation to those at risk. DHA levels are low despite high levels of ALA suggesting that supplementation, if indicated, should be with preformed DHA rather than with its precursors.
    03/2015; 21. DOI:10.1007/8904_2014_399
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    ABSTRACT: Phenylketonuria (PKU) is an inborn error of phenylalanine (Phe) metabolism caused by the deficiency of phenylalanine hydroxylase. This deficiency leads to the accumulation of Phe and its metabolites in tissues and body fluids of PKU patients. The main signs and symptoms are found in the brain but the pathophysiology of this disease is not well understood. In this context, metabolic alterations such as oxidative stress, mitochondrial dysfunction, and impaired protein and neurotransmitters synthesis have been described both in animal models and patients. This review aims to discuss the main metabolic disturbances reported in PKU and relate them with the pathophysiology of this disease. The elucidation of the pathophysiology of brain damage found in PKU patients will help to develop better therapeutic strategies to improve quality of life of patients affected by this condition.
    Aging and Disease 10/2015; 6(5):390-9. DOI:10.14336/AD.2015.0827 · 3.07 Impact Factor