Dietary interventions for phenylketonuria.

BACKGROUND: Phenylketonuria is an inherited disease treated with dietary restriction of the amino acid phenylalanine. The diet is initiated in the neonatal period to prevent mental handicap; however, it is restrictive and can be difficult to follow. Whether the diet can be relaxed or discontinued during adolescence or should be continued for life remains a controversial issue, which we aim to address in this review. OBJECTIVES: To assess the effects of a low-phenylalanine diet commenced early in life for people with phenylketonuria. To assess the possible effects of relaxation or termination of the diet on intelligence, neuropsychological outcomes and mortality, growth, nutritional status, eating behaviour and quality of life. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings.Most recent search of the Inborn Errors of Metabolism Trials Register: 05 March 2009. SELECTION CRITERIA: All randomised or quasi-randomised controlled trials comparing a low-phenylalanine diet to relaxation or termination of dietary restrictions in people with phenylketonuria. DATA COLLECTION AND ANALYSIS: Two authors independently assessed study eligibility and methodological quality, and subsequently extracted the data. MAIN RESULTS: We included four studies in this review (251 participants), and found few significant differences between treatment and comparison groups for the outcomes of interest. Blood phenylalanine levels were significantly lower in participants with phenylketonuria following a low-phenylalanine diet compared to those on a less restricted diet, mean difference (MD) at three months -698.67 (95% confidence interval (CI) -869.44 to -527.89). Intelligence quotient was significantly higher in participants who continued the diet than in those who stopped the diet, MD after 12 months 5.00 (95% CI 0.40 to 9.60). However, these results came from a single study. AUTHORS' CONCLUSIONS: The results of non-randomised studies have concluded that a low-phenylalanine diet is effective in reducing blood phenylalanine levels and improving intelligence quotient and neuropsychological outcomes. We were unable to find any randomised controlled studies that have assessed the effect of a low-phenylalanine diet versus no diet from diagnosis. In view of evidence from non-randomised studies, such a study would be unethical and it is recommended that low-phenylalanine diet should be commenced at the time of diagnosis. There is uncertainty about the precise level of phenylalanine restriction and when, if ever, the diet should be relaxed. This should be addressed by randomised controlled studies.

Oral protein energy supplements for children with cystic fibrosis: CALICO multicentre randomised controlled trial.

OBJECTIVE: To determine whether oral protein energy supplements, used long term in children with cystic fibrosis who are moderately malnourished, improve nutritional and other outcomes. DESIGN: Multicentre randomised controlled trial. SETTING: Seven specialist paediatric cystic fibrosis centres and their associated shared care clinics and seven smaller paediatric cystic fibrosis clinics. PARTICIPANTS: 102 children with cystic fibrosis, aged between 2 and 15 years, who were moderately malnourished. INTERVENTIONS: Oral protein energy supplements in addition to usual dietary advice compared with dietary advice alone, for 12 months. MAIN OUTCOME MEASURE: Change in body mass index centile over one year. RESULTS: Use of supplements was not associated with a change in body mass index centile (mean difference 2.99 centile points, 95% confidence interval -2.70 to 8.68) or other nutritional and spirometric outcomes in this group of children. CONCLUSIONS: Long term use of oral protein energy supplements did not result in an improvement in nutritional status or other clinical outcomes in children with cystic fibrosis who were moderately malnourished. Oral protein energy supplements should not be regarded as an essential part of the management of this group of children. TRIAL REGISTRATION: ISRCTN: 95744468.

A survey of psychological wellbeing in an adult population.

The British government has called on all NHS staff to help promote good psychological wellbeing in the population. This article reports results from a survey conducted in Merseyside, England, into the prevalence of poor psychological wellbeing across a large part of the region. People registered with one of five Merseyside primary care trusts were stratified by age group and deprivation, and a questionnaire was mailed to 28,000 who had been randomly selected from those aged 15 or over. A total of 11,168 (45%) completed questionnaires were returned. Of these, 2,442 (21.9%) respondents rated their psychological wellbeing as fairly poor or very poor. Mean levels of psychological wellbeing were significantly worse in a number of readily identifiable groups within the population, but overall, the lowest wellbeing ratings were concentrated in the most socioeconomically deprived quartile. We make a number of practical suggestions for the role of the community nurse in promoting good psychological wellbeing in patients. We also highlight our finding that socioeconomic deprivation was strongly associated with poor psychological wellbeing, which was in turn associated with a lifestyle high in risk factors for non-communicable diseases.

Oral protein-energy supplements for children with chronic disease: systematic review.

Growth failure and poor nutritional status are features of children with chronic disease. Oral protein-energy supplements are one of a number of interventions provided with the aim of improving nutritional status in these children. The present paper describes a Cochrane systematic review assessing the efficacy of these products in children with chronic disease. The objective was to examine the evidence that in children with chronic disease oral protein-energy supplements alter nutrient intake, nutritional indices, survival and quality of life. All randomised controlled trials of the use of oral protein-energy supplements in children with chronic disease were identified through searching electronic databases and hand searching the abstract books of nutrition conferences. Studies identified were independently assessed for eligibility and methodological quality, and data on outcomes of interest were combined in a meta-analysis where possible. Two trials were eligible for inclusion in the review, both of which were undertaken with children with cystic fibrosis. No statistical differences could be found between treatment and control groups when data from both studies were combined. Oral protein-energy supplements are widely used to improve the nutritional status of children with chronic disease. No conclusions can be drawn on the efficacy of these products based on the limited data available. Further randomised controlled trials are required to investigate the use of these products in children with chronic disease. Until further data are available, these products should be used with caution.