Evolution of nutritional management in children with cystic fibrosis - a narrative review.

Nutrition has played a central role in the management and outcomes of people with cystic fibrosis (pwCF) since the 1970s. Advances in therapies and practices in recent decades have led to a significant change in the patient landscape with dramatic improvements in life expectancy, as well as quality of life, bringing with it new issues. Historically, cystic fibrosis was a condition associated with childhood and malnutrition; however, changes in patient demographics, nutritional assessment and fundamental nutritional management have evolved, and it has become an increasingly prevalent adult disease with new nutritional challenges, including obesity. This paper aims to describe these changes and the impact and challenges they bring for those working in this field. Nutritional professionals will need to evolve, adapt and remain agile to the wider range of situations and support required for a new generation of pwCF. Specialised nutrition support will continue to be required, and it will be additionally important to improve and optimise quality of life and long-term health.

Evaluación de la técnica de conteo de grasas y ajuste de enzimas pancreáticas en un grupo de pacientes con insuficiencia pancreática secundaria a fibrosis quística con seguimiento en un hospital de alta complejidad / Evaluation of the fat counting technique and pancreatic enzyme adjustment in a group of patients with pancreatic insufficiency secondary to cystic fibrosis followed-up in a tertiary-level hospital

Objetivo: evaluar la efectividad de la técnica de conteo de grasas y ajuste de enzimas pancreáticas en un grupo de pacientes con insuficiencia pancreática secundaria a fibrosis quística (FQ). Materiales y métodos: En un grupo de pacientes con FQ, sin otra patología asociada, mayores de 1 año, con >10 000 UKD (unidades por kilo por día) de lipasa; se realizó educación y aplicación de técnica de conteo de grasas con ajuste enzimático, solicitando Van de Kamer y registro alimentario de 5 días durante la recolección de la muestra con un intervalo de 3 meses entre ambas determinaciones. Se evaluó la efectividad de la misma y las dosis de enzimas utilizadas mediante el porcentaje de excreción grasa (PEG), así como las variaciones en la cantidad de enzimas utilizadas y la ganancia de peso. Los datos se registraron en RED Cap (Research Electronic Data Capture) y se analizaron mediante Stata 12. Resultados: De un total de 21 pacientes, 16 completaron la intervención. El 50% presentó un índice de masa corporal (IMC) mayor del Plo 25 antes y después, un 87% alcanzó adecuación calórica mayor del 120% de la ingestas diarias recomendadas (RDA) al final, logrando un aumento promedio de z score de peso de 0,28 con una media inicial de 17 kg y final de 18,2 kg. En cuanto a la media del requerimiento enzimático fue de 14 800 UKD antes y 10 145 UKD después (z=0,002), asimismo el porcentaje de excreción grasa (PEG) tuvo una disminución del 38% (p=0,1705). Conclusiones: La implementación de la técnica de conteo de grasas y ajuste enzimático, podría ser una estrategia válida para aquellos pacientes con FQ que tienen dosis altas de enzimas e inadecuada ganancia de peso (AU)

Objective: To evaluate the effectiveness of the fat counting technique and pancreatic enzyme adjustment in a group of patients with pancreatic insufficiency secondary to cystic fibrosis (CF). Materials and methods: A group of patients with CF without other associated diseases, older than 1 year of age, lipase dose >10 000 UKD (units per kilo per day), received education on the fat counting technique with enzyme adjustment followed by its implementation of the intervention. Van de Kamer was requested and a 5-day food record was kept during the sample collection with an interval of 3 months between both measurements. The effectiveness of the technique and the enzyme doses used were evaluated based on the percentage of fat excretion (PFE), as well as the variations in the amount of enzymes used and weight gain. Data were recorded in RED Cap (Research Electronic Data Capture) and analyzed using Stata 12. Results: Of a total of 21 patients, 16 completed the intervention. Fifty percent had a body mass index (BMI) greater than Plo 25 before and after the intervention; 87% had achieved a caloric increase greater than 120% of the recommended daily intake (RDA) at the end of the study and an average increase in weight z score of 0.28 with an initial mean of 17 kg and a final mean of 18.2 kg. Mean enzyme requirement was 14 800 UKD before and 10 145 UKD after the intervention (z=0.002). PFE decreased by 38% (p=0.1705). Conclusions: The implementation of the technique of fat counting and enzyme adjustment may be a valid strategy for CF patients with high enzyme doses and inadequate weight gain. (AU)

Impact of guideline-recommended dietitian assessments on weight gain in infants with cystic fibrosis.

BACKGROUND: Cystic fibrosis (CF)-specialized nutrition care strives to meet normal infant growth, but the relationship of dietitian assessments to weight outcomes is unknown. We characterize nutrition management for inadequate weight gain and assess association of dietitian assessments and center-level weight-for-age Z-scores (WAZ). METHODS: We used encounter data from 226 infants across 28 US CF Centers from the Baby Observational Nutritional study between January 2012 through December 2017. We identified dietitian assessments and consensus guideline-recommended responses to inadequate weight gain: calorie increases, pancreatic enzyme replacement therapy (PERT) increases, or shortened time to next visit. We compared center assessments by funnel plot and summarize median WAZ by center. RESULTS: Of 2,527 visits, 808 (32%) visits had identified inadequate weight gain, distributed in 216 infants. Assessments occurred in 1953 visits (77%), but varied widely between centers (range 17% - 98%). For inadequate weight gain, most and least common responses were calorie increase (64%) and PERT increase (21%). Funnel plot analysis identified 4 high-performers for frequent dietitian assessments (range 92% - 98%) and 4 under-performers (range 17% - 56%). High-performers treated inadequate weight gain more often with adequate calories (24/30, 80% v. 12/23, 52%) and closer follow up (104/164, 63% v. 60/120, 49%) compared to under-performers. Three of 4 high-performing sites met center nutrition goals for positive median WAZ at 2 years old unlike 3 under-performers (WAZHigh 0.33 v. WAZLow -0.15), despite similar patient characteristics. CONCLUSION: We characterized multicenter variation in dietitian assessments, identifying opportunities to improve care delivery to target early nutrition outcomes.

Fat-Soluble Vitamin Supplementation Using Liposomes, Cyclodextrins, or Medium-Chain Triglycerides in Cystic Fibrosis: A Randomized Controlled Trial.

Fat-soluble vitamin deficiency remains a challenge in cystic fibrosis (CF), chronic pancreatitis, and biliary atresia. Liposomes and cyclodextrins can enhance their bioavailability, thus this multi-center randomized placebo-controlled trial compared three-month supplementation of fat-soluble vitamins in the form of liposomes or cyclodextrins to medium-chain triglycerides (MCT) in pancreatic-insufficient CF patients. The daily doses were as follows: 2000 IU of retinyl palmitate, 4000 IU of vitamin D3, 200 IU of RRR-α-tocopherol, and 200 µg of vitamin K2 as menaquinone-7, with vitamin E given in soybean oil instead of liposomes. All participants received 4 mg of ß-carotene and 1.07 mg of vitamin K1 to ensure compliance with the guidelines. The primary outcome was the change from the baseline of all-trans-retinol and 25-hydroxyvitamin D3 concentrations and the percentage of undercarboxylated osteocalcin. Out of 75 randomized patients (n = 28 liposomes, n = 22 cyclodextrins, and n = 25 MCT), 67 completed the trial (89%; n = 26 liposomes, n = 18 cyclodextrins, and n = 23 MCT) and had a median age of 22 years (IQR 19-28), body mass index of 20.6 kg/m2 [18.4-22.0], and forced expiratory volume in 1 s of 65% (44-84%). The liposomal formulation of vitamin A was associated with the improved evolution of serum all-trans-retinol compared to the control (median +1.7 ng/mL (IQR -44.3-86.1) vs. -38.8 ng/mL (-71.2-6.8), p = 0.028). Cyclodextrins enhanced the bioavailability of vitamin D3 (+9.0 ng/mL (1.0-17.0) vs. +3.0 ng/mL (-4.0-7.0), p = 0.012) and vitamin E (+4.34 µg/mL (0.33-6.52) vs. -0.34 µg/mL (-1.71-2.15), p = 0.010). Liposomes may augment the bioavailability of vitamin A and cyclodextrins may strengthen the supplementation of vitamins D3 and E relative to MCT in pancreatic-insufficient CF but further studies are required to assess liposomal vitamin E (German Clinical Trial Register number DRKS00014295, funded from EU and Norsa Pharma).

Adherence to Dietary Recommendations, Nutrient Intake Adequacy and Diet Quality among Pediatric Cystic Fibrosis Patients: Results from the GreeCF Study.

Nutrition is an important component of cystic fibrosis (CF) therapy, with a high-fat diet being the cornerstone of treatment. However, adherence to the dietary recommendations for CF appears suboptimal and burdensome for most children and adolescents with CF, leading to malnutrition, inadequate growth, compromised lung function and increased risk for respiratory infections. A cross-sectional approach was deployed to examine the degree of adherence to the nutrition recommendations and diet quality among children with CF. A total of 76 children were recruited from Aghia Sophia's Children Hospital, in Athens, Greece. In their majority, participants attained their ideal body weight, met the recommendations for energy and fat intake, exceeding the goal for saturated fatty acids consumption. Carbohydrate and fiber intake were suboptimal and most participants exhibited low or mediocre adherence to the Mediterranean diet prototype. It appears that despite the optimal adherence to the energy and fat recommendations, there is still room for improvement concerning diet quality and fiber intake.

Efectividad de ivacaftor en la fibrosis quística: mejoría de la cirrosis hepática y de los parámetros nutricionales y respiratorios / Effectiveness of ivacaftor in cystic fibrosis: Improvement of liver cirrhosis, nutritional status and respiratory function

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Omega-3 fatty acid supplementation for cystic fibrosis.

BACKGROUND: Studies suggest that a diet rich in omega-3 essential fatty acids may have beneficial anti-inflammatory effects for chronic conditions such as cystic fibrosis. This is an updated version of a previously published review. OBJECTIVES: To determine whether there is evidence that omega-3 polyunsaturated fatty acid supplementation reduces morbidity and mortality and to identify any adverse events associated with supplementation. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of last search: 01 April 2020. We also searched online study registries and contacted authors. Date of last search: 12 February 2020. SELECTION CRITERIA: Randomised controlled trials in people with cystic fibrosis comparing omega-3 fatty acid supplements with placebo. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies for inclusion, extracted data and assessed the risk of bias of the studies. The quality of the evidence was assessed using GRADE. MAIN RESULTS: The searches identified 23 studies; five studies with 106 participants (children and adults) were included; duration of studies and interventions differed. Two studies compared omega-3 fatty acids to olive oil for six weeks; one study compared omega-3 fatty acids and omega-6 fatty acids to control capsules (customised fatty acid blends) for three months; one study compared a liquid dietary supplement containing omega-3 fatty acids to one without for six months; and one study compared omega-3 fatty acids to a placebo for 12 months. Three studies had a low risk of bias for randomisation, but the risk was unclear in the remaining two studies; all studies had an unclear risk of bias for allocation concealment. Three of the studies adequately blinded participants; the risk of bias for selective reporting was high in one study and unclear for four studies. Two studies reported the number of respiratory exacerbations. At three months, one study (43 participants) reported no change in antibiotic usage. At 12 months the second study (15 participants) reported a reduction in the number of pulmonary exacerbations and cumulative antibiotic days in the supplement group compared to the previous year (no data for the control group); very low-quality evidence means we are unsure whether supplementation has any effect on this outcome. With regards to adverse events, one six-week study (12 participants) reported no difference in diarrhoea between omega-3 or placebo capsules; the very low-quality evidence means we are unsure if supplementation has any effect on this outcome. Additionally, one study reported an increase in steatorrhoea requiring participants to increase their daily dose of pancreatic enzymes, but three studies had already increased pancreatic enzyme dose at study begin so as to reduce the incidence of steatorrhoea. One study (43 participants) reported stomach pains at three months (treatment or control group not specified). One six-week study (19 participants) reported three asthma exacerbations leading to exclusion of participants since corticosteroid treatment could affect affect essential fatty acid metabolism. Four studies reported lung function. One six-week study (19 participants) reported an increase in forced expiratory volume in one second (FEV1) (L) and forced vital capacity (FVC) (L), but the very low-quality evidence means we are unsure if supplementation has any effect on lung function. The remaining studies did not report any difference in lung function at three months (unit of measurement not specified) or at six months and one year (FEV1 % predicted and FVC % predicted). No deaths were reported in any of the five studies. Four studies reported clinical variables. One study reported an increase in Schwachman score and weight alongside a reduction in sputum volume with supplementation compared to placebo at three months (data not analysable). However, three studies reported no differences in either weight at six weeks, in body mass index (BMI) standard deviation (SD) score at six months (very low-quality evidence) or BMI Z score at 12 months. Three studies reported biochemical markers of fatty acid status. One study showed an increase from baseline in both EPA and DHA content of serum phospholipids in the omega-3 group compared to placebo at three months and also a significant decrease in n-6/n-3 ratio in the supplement group compared to placebo; since the quality of the evidence is very low we are not certain that these changes are due to supplementation. One six-month cross-over study showed a higher EPA content of the neutrophil membrane in the supplement group compared to the placebo group, but, no difference in DHA membrane concentration. Furthermore, the leukotriene B4 to leukotriene B5 ratio was lower at six months in the omega-3 group compared to placebo. A one-year study reported a greater increase in the essential fatty acid profile and a decrease in AA levels in the treatment arm compared to placebo. AUTHORS' CONCLUSIONS: This review found that regular omega-3 supplements may provide some limited benefits for people with cystic fibrosis with relatively few adverse effects: however, the quality of the evidence across all outcomes was very low. The current evidence is insufficient to draw firm conclusions or recommend routine use of these supplements in people with cystic fibrosis. A large, long-term, multicentre, randomised controlled study is needed to determine any significant therapeutic effect and to assess the influence of disease severity, dosage and duration of treatment. Future researchers should note the need for additional pancreatic enzymes when providing omega-3 supplementation or olive oil placebo capsules. More research is required to determine the exact dose of pancreatic enzyme required.

Effects of low glycemic index/high-fat, high-calorie diet on glycemic control and lipid profiles of children and adolescence with cystic fibrosis: A randomized double-blind controlled clinical trial.

PURPOSE: Low glycemic index diets seem to be potentially effective to improve glycemic control and reduce lipid profiles. Hence, this study aimed to evaluate the effect of a low glycemic index/high fat, high-calorie diet on glycemic status and lipid profiles of patients with cystic fibrosis. METHODS: In this randomized clinical trial, 44 children and adolescents with cystic fibrosis were randomized to receive for three months either a high fat, high-calorie diet (n = 22) or a low glycemic index/high fat, high-calorie diet (n = 22) with similar calorie and macronutrients composition. Patients in high fat, high-calorie diet arm were allowed to use all sources of carbohydrates with different glycaemic indices; whereas those in another arm consumed carbohydrates from low glycemic index sources. Serum levels of lipid profiles (triglyceride, total cholesterol, HDL cholesterol, LDL cholesterol), insulin, fasting blood glucose, and glycated hemoglobin were measured at baseline and after the intervention. RESULTS: Between-group differences were significant only for fasting blood glucose (P < 0.001). However, fasting blood glucose (P = 0.003) and glycated hemoglobin (P = 0.002) significantly decreased after the intervention in the low glycemic index group, while in another group a significant increase in fasting blood glucose (P = 0.038) and triglyceride (P = 0.004) was found. No significant within-group differences were observed in other variables in both groups. CONCLUSIONS: It seems that adherence to a low glycemic index/high fat, high-calorie diet can improve glycemic indices in children and adolescents with cystic fibrosis compared to the high fat, high-calorie diet. TRIAL REGISTRATION: IRCT2017102325267N5.

Challenges with optimizing nutrition in cystic fibrosis.

Introduction. Optimizing nutrition remains the cornerstone of therapy for patients with cystic fibrosis (CF) since it is associated with better pulmonary function and survival. However, a significant proportion of patients still fail to achieve normal growth and nutritional status. Areas covered. This review describes the current challenges in providing effective nutritional therapy in CF with a focus on the current issues related to energy imbalance, dietary composition, adherence to nutritional recommendations, pancreatic enzyme replacement therapy, and the effects of modulators of the CF transmembrane conductance regulator. Expert opinion. CF is a multisystemic disease that requires a personalized nutritional approach with accurate evaluation of energy balance. There is an urgent need for evidence-based recommendations on the dietary composition, in consideration of the increasing prevalence of overweight, diabetes and the potential effects of fatty acids on inflammation and immune response. More research into new pancreatic enzyme formulations is also required.

Adherence to Nutritional Supplementation in Cystic Fibrosis.

PURPOSE: The purpose of this study was to examine patterns of adherence to a novel dietary supplement in pediatric cystic fibrosis. Adherence to dietary supplementation in cystic fibrosis is challenging, and examination of patterns of adherence behavior over time is needed to better characterize subgroups of patients who need self-management support. DESIGN AND METHODS: We prospectively examined adherence to Lym-X-Sorb™ (LXS), an organized lipid matrix dietary supplementation for patients with cystic fibrosis (CF) and pancreatic insufficiency (PI), over a 12-month period. Adherence for participants aged 5-17 years with CF and PI (N = 109) was monitored monthly via supplement packet counts. Group-based trajectory modeling was employed to examine patterns in adherence behavior over time. RESULTS: Four distinct trajectories best characterized adherence in this sample, with 18% of participants demonstrating near perfect adherence, 42% demonstrating good adherence (at or above 80%), 16% demonstrating poor adherence that declined over time, and 24% demonstrating significant non-adherence (< 30%). CONCLUSIONS: Some patients with CF and PI who are prescribed nutritional supplements will require intensive, individualized behavioral intervention to enhance adherence. Identifying patients who will have difficulty adhering to dietary interventions may result in better treatment-to-patient matching and improved adherence promotion efforts. PRACTICE IMPLICATIONS: Assessment of adherence to dietary supplementation over time can identify patients at risk for continued difficulty with self-management and provide opportunities for early intervention.

The Relative Contribution of Food Groups to Macronutrient Intake in Children with Cystic Fibrosis: A European Multicenter Assessment.

BACKGROUND: Optimal nutrition for children with cystic fibrosis (CF) improves prognosis and survival, but an increased caloric intake recommendation for this population raises concerns about the nutrient profile of their diets. OBJECTIVE: Our aim was to assess the relative contribution of food groups to the total macronutrient intake of European pediatric patients with CF. DESIGN: We conducted a cross-sectional study in which the participants recorded dietary intake from 2016 to 2017. Specifically developed nutritional composition databases were used to obtain nutritional data, including macronutrients and food groups, according to previously standardized criteria. PARTICIPANTS/SETTING: Two hundred and seven pediatric patients with CF from six European centers were involved in the My App for Cystic Fibrosis self-management project. MAIN OUTCOME MEASURES: Participants reported dietary intake with a detailed 4-day food record. STATISTICAL ANALYSIS PERFORMED: Descriptive analyses of nutrient intake, food group consumption, and dietary origin of macronutrients were conducted with R software. RESULTS: Similar patterns were found in nutrient and food group intake; both sugar and saturated fatty acids contributed >10% each to the total daily energy intake in all the centers. Large mean and median percent differences were observed in the intake of other nutrient and food groups, because sweets and snacks were consumed once or twice a day, and fruit and vegetables were consumed two or three times a day. Milk, meat, sweets and snacks, and oils were the main sources of fat in all centers. CONCLUSIONS: Study findings indicated less than optimal nutrient profiles, especially for sugars and saturated fatty acids, resulting from the high consumption of meat, dairy, and processed products and low consumption of fish, nuts, and legumes. These results can serve as a basis for future tailored interventions that target improved adherence to nutritional recommendations for patients with CF.

Nutritional Treatment of a Young Infant with Cystic Fibrosis Presenting with Severe Kwashiorkor Dermatosis.

Kwashiorkor in infancy is typically associated to an underlying disease. Edema, a striking feature of this type of malnutrition, can be difficult to assess in this age group. The typical dermatosis of Kwashiorkor is not fully explained the deficiency of one isolated vitamin or micronutrient. This article presents an infant with cystic fibrosis, who developed Kwashiorkor in the third month of life with extensive cutaneous manifestations. An early, individualized and aggressive nutritional intervention with optimized supplementationof sulfur amino acids, vitamins and micronutrients was established, with impressively recovery of overall nutrition and skin manifestations in a relatively short period of time.

The nutritional status in CF: Being certain about the uncertainties.

BACKGROUND: Nutritional therapy is one of the cornerstones in cystic fibrosis (CF) therapy. There is a strong association between nutritional status and pulmonary function and thus longevity. Therefore nutritional therapy should be continuously adapted to preserve or improve the nutritional status. This narrative review was written to reconsider nutritional therapy in CF based on the latest evidence available since the publication of the ESPEN - ESPGHAN - ECFS guidelines on nutrition care for infants, children and adults with CF. METHODS: A literature search in Pubmed, Scopus and Web of Science was conducted to identify new research focusing on the use of growth charts, body composition, protein intake and pancreatic enzyme therapy (PERT) in CF between June 2014 and June 2017. RESULTS: The search strategy resulted in a total of 1810 hits across the databases. After reviewing title and abstract only 17 studies were included of which 2 animal studies. The use of growth charts was discussed in 3 studies, body composition in 6, protein intake and digestion in 4 and PERT in 4. CONCLUSION: According to the current guidelines and the available evidence of the discussed topics, it is important that the nutritional therapy in CF is redefined according to age, pancreatic function and disease stage. Macronutrients balances are of importance and change over lifetime. As a consequence an accurate PERT intake is required and thus further research on timing and dosage is necessary. To improve the nutritional assessment a proper use of the growth charts and a consensus on body composition measurements, references and thresholds is advised.

A comprehensive evaluation of omega-3 fatty acid supplementation in cystic fibrosis patients using lipidomics.

The evaluation of the benefits of omega-3 fatty acid supplementation in humans requires the identification and characterization of suitable biomarkers of its incorporation in the body. The reference method for the evaluation of omega-3, gas chromatography, is difficult to apply in clinical practice because of its low throughput and does not provide information about the incorporation of specific fatty acids in lipid species and the potential effects of supplementation on lipid classes. We used a quantitative lipidomic approach to follow the incorporation of omega-3 fatty acids into plasma lipids in cystic fibrosis patients (n=50) from a randomized controlled clinical trial after the supplementation of seaweed oil enriched with docosahexaenoic acid (DHA). Lipidomic analysis accurately showed the distribution of fatty acids in different lipid classes after omega-3 supplementation, and the performance in determining the compliance to supplementation was similar to that of gas chromatography coupled to mass spectrometry. Twelve months after fatty acid supplementation, DHA was predominantly incorporated into highly unsaturated cholesteryl esters (110.9±16.2 vs. 278.6±32.6 µM, mean±S.E.M.) and phosphatidylcholine (142.4±11.9 vs. 272.9±21.4 µM) and, to a lesser extent, into phosphatidylethanolamine (9.4±0.8 vs. 15.5±1.5 µM) and triglycerides (0.4±0.04 vs. 1.1±0.12 µM). In addition, a technique was developed for the fast measurement of the DHA/arachidonic acid ratio to simplify the follow-up of nutritional intervention with DHA-enriched foods. We conclude that lipidomics is a suitable approach for monitoring the incorporation of omega-3 fatty acids in nutritional studies.

Dietary interventions for managing glucose abnormalities in cystic fibrosis: a systematic review protocol.

BACKGROUND: Glucose abnormalities in cystic fibrosis (CF) are common, but there is limited evidence to guide their dietary management. Progressive impaired glucose tolerance eventually leads to cystic fibrosis-related diabetes (CFRD), the most prevalent complication of CF, which is associated with increased morbidity and mortality. Optimising glycaemic control improves clinical status and reduces mortality; insulin therapy is the primary means of controlling glycaemia in CFRD, but its role in managing pre-diabetes is less clear. CF dietary therapy requires a high calorie diet due to increased energy expenditure and malabsorption, but this energy-dense diet is typically high in fat and sugar, and high sugar intakes often result in hyperglycaemia in individuals who have impaired glucose handling. Current guidelines for the dietary management of glucose abnormalities in CF are based on clinical consensus rather than empirical evidence. A systematic review conducted in 2012 on the effects of low glycaemic index dietary intervention in CF concluded that there is a dearth of evidence in this area. This review will update the systematic review by Balzer et al. in 2012 and will broaden the scope of their review to include any type of dietary intervention for managing glucose abnormalities in CF. METHODS: Quantitative studies of dietary interventions to manage glucose abnormalities in individuals aged over 5 years with CF and glucose abnormalities will be reviewed. No limits will be placed on language or study design. The comparator will be standard CF dietary therapy (energy dense, high-fat diet) in addition to insulin therapy for individuals with CFRD. Electronic databases will be searched for completed quantitative studies published in peer-review journals that focus on dietary interventions for managing glucose abnormalities in CF. Searches will be conducted from 2000 up to the present day to reflect the evolving improvements in CF management. No restrictions will be placed on study design or language. Duration of the dietary intervention must be a minimum of 2 months and only interventions in out-patient or community settings will be included. Studies must report on dietary intervention, glycaemic control, anthropometry and lung function. Evidence will be assessed for heterogeneity and a narrative review or meta-analysis conducted as appropriate. DISCUSSION: This systematic review will elucidate current knowledge of the effects of dietary interventions for managing glucose abnormalities in the vulnerable CF clinical population. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number: CRD42018085569 www.crd.york.ac.uk/prospero/.

Nutritional management of cystic fibrosis - an update for the 21st century.

Nutritional management is an essential part of multidisciplinary care for infants, children and adults with cystic fibrosis (CF). In 2016 two updated nutritional consensus guidelines were published [1,2]. This review will explore some of the key points in the nutritional management of people with CF in the 21st Century.

Role of vitamin D on gut microbiota in cystic fibrosis.

This review explores the potential for vitamin D to favorably alter the gut microbiota, given emerging evidence of the role of vitamin D in controlling mucosal inflammation in the gut. It will focus on cystic fibrosis (CF) patients, a population with both vitamin D deficiency due to gut malabsorption and an altered gut microbiota composition. Recent evidence shows that vitamin D acts to maintain the integrity of the gut mucosal barrier by enhancement of intercellular junctions that control mucosal permeability and reduction of pro-inflammatory cytokines such as IL-8. In addition, vitamin D receptor-mediated signaling has been shown to inhibit inflammation-induced apoptosis of intestinal epithelial cells. As a result of these effects on the intestinal mucosa, maintenance of sufficient vitamin D status may be essential for the development of a healthy gut microbiota, particularly in conditions defined by chronic mucosal inflammation such as CF. We hypothesize here that high dose vitamin D may be used to favorably manipulate the aberrant mucosa seen in patients with CF. This may result in improved clinical outcomes in association with a low inflammatory environment that allows beneficial bacteria to outcompete opportunistic pathogens. Current evidence is sparse but encouraging, and additional evidence is needed to establish vitamin D as a therapeutic approach for gut microbiota modification.