Cystic fibrosis: nutritional status and micronutrients

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

The role of neonatal screening in nutritional evolution in the first 12 months after diagnosis of cystic fibrosis

OBJECTIVE

to assess the progression of pediatric cystic fibrosis (CF) patients' nutritional status during the first 12 months after diagnosis and to establish its association with neonatal screening and clinical variables. Patients were recruited from two reference centers in Southern Brazil.

METHODS

Retrospective cohort study was carried out with all the patients diagnosed between 2009 and 2014. Anthropometric, clinic and neonatal screening were collected from medical files. Analysis of anthropometric markers over time was performed by generalized estimating equations. A multivariate regression analysis model to predict the Δ percentile body mass index (BMI) (BMI percentile difference between one year after the treatment and BMI percentile at diagnosis) was done.

RESULTS

Forty-seven patients were included in the study. Analysis of nutritional data over the period between six months and one year after diagnosis showed significant improvement of BMI, weight/age and weight/height percentiles and Z scores. The neonatal screening was associated with a significant increase of 31.2 points in ΔBMI percentile at the one-year evaluation (p<0.05). On the other hand, a one-point increase of initial BMI percentile was associated with a reduction of 0.6 points in ΔBMI percentile.

CONCLUSION

This study demonstrated the role of neonatal screening in the nutritional status of patients diagnosed with CF in the first year after diagnosis. Early diagnosis can significantly contribute to the achievement of appropriate anthropometric indicators and important nutritional recovery of CF patients.

Validation of a Nutrition Screening Tool for Pediatric Patients with Cystic Fibrosis

BACKGROUND

In cystic fibrosis (CF), nutrition diagnosis is of critical relevance because the early identification of nutrition-related compromise enables early, adequate intervention and, consequently, influences patient prognosis. Up to now, there has not been a validated nutrition screening tool that takes into consideration clinical variables.

OBJECTIVE

To validate a specific nutritional risk screening tool for patients with CF based on clinical variables, anthropometric parameters, and dietary intake.

DESIGN

Cross-sectional study. The nutrition screening tool was compared with a risk screening tool proposed by McDonald and the Cystic Fibrosis Foundation criteria.

PARTICIPANTS/SETTING

Patients aged 6 to 18 years, with a diagnosis of CF confirmed by two determinations of elevated chloride level in sweat (sweat test) and/or by identification of two CF-associated genetic mutations who were receiving follow-up care through the outpatient clinic of a Cystic Fibrosis Treatment Center.

MAIN OUTCOME MEASURES

Earlier identification of nutritional risk in CF patients aged 6 to 18 years when a new screening tool was applied.

STATISTICAL ANALYSES PERFORMED

Agreement among the tested methods was assessed by means of the kappa coefficient for categorical variables. Sensitivity, specificity, and accuracy values were calculated. The significance level was set at 5% (P<0.05). Statistical analyses were carried out in PASW Statistics for Windows version 18.0 (2009, SPSS Inc).

RESULTS

Eighty-two patients (49% men, aged 6 to 18 years) were enrolled in the study. The agreement between the proposed screening tool and the tool for screening nutritional risk for CF by the McDonald method was good (κ=0.804; P<0.001) and the sensitivity and specificity was 85% and 95%, respectively. Agreement with the Cystic Fibrosis Foundation criteria was lower (κ=0.418; P<0.001), and the sensitivity and specificity were both 72%.

CONCLUSIONS

The proposed screening tool with defined clinical variables promotes earlier identification of nutritional risk in pediatric patients with CF.

Dietary intake and nutritional status of micronutrients in adults with cystic fibrosis in relation to current recommendations

An increased prevalence of cystic fibrosis (CF) related complications such as impaired bone health and diabetes has accompanied increased survival of patients with CF. This review was conducted to determine the extent to which adults with CF are meeting current nutrition recommendations for micronutrients in association with CF-related complications management. Although dietary intake and nutritional status in CF has improved significantly in recent decades, micronutrient status seems to have diverged. While vitamin A and E intakes appear adequate, frequent vitamin D and K deficiency/insufficiency and compromised bone health in CF, occurs despite supplementation. Although deficiency of water-soluble vitamins and minerals is uncommon, ongoing surveillance will enhance overall health outcomes, particularly in cases of CF-related liver disease and deteriorated lung function and bone health. Salt and fluid status in CF may also need attention due to diminished thirst sensation and voluntary rehydration. Further investigation in micronutrient status optimisation in CF will inform the development of more effective and targeted nutrition therapies to enable integration of more refined recommendations for micronutrient intakes in CF based on individual needs and disease progression.

Indicadores antropométricos e de ingestão alimentar como preditores da função pulmonar em pacientes com fibrose cística

OBJETIVO: Avaliar se indicadores antropométricos e de ingestão alimentar são preditores da função pulmonar em pacientes com fibrose cística (FC). MÉTODOS: Estudo transversal com 69 pacientes (variação, 5,4-16,5 anos de idade) diagnosticados com FC e em acompanhamento no Hospital de Clínicas de Porto Alegre, em Porto Alegre (RS). A avaliação antropométrica consistiu nas medidas do índice de massa corpórea (IMC), da circunferência muscular do braço (CMB) e da dobra cutânea tricipital (DCT). A ingestão alimentar foi avaliada pelo recordatório de ingestão habitual e comparada com recommended dietary allowances. A avaliação da função pulmonar foi realizada através da capacidade ventilatória, representada pelo VEF1. Razões de prevalência foram calculadas entre os preditores e o desfecho estudado (VEF1 < 80% do previsto). RESULTADOS: Os pacientes com CMB e DCT abaixo do percentil 25 apresentaram significativamente maior prevalência de VEF1 < 80% do previsto (p < 0,001 e p = 0,011, respectivamente). Os pacientes com IMC menor que o percentil 50 apresentaram 4,43 vezes (IC95%: 1,58-12,41) a prevalência de VEF1 < 80% do previsto. Os pacientes colonizados por Staphylococcus aureus resistente a meticilina apresentaram 2,54 vezes (IC95%: 1,43-4,53) a prevalência do desfecho do que os não colonizados. A associação entre consumo calórico e o desfecho estudado apresentou significância limítrofe (IC95%: 0,95-3,45). CONCLUSÕES: O IMC superior ao percentil 50 e a ausência de colonização por S. aureus resistente a meticilina apresentaram uma associação direta com função pulmonar preservada em pacientes com FC.

Bioavailability and safety of a high dose of docosahexaenoic acid triacylglycerol of algal origin in cystic fibrosis patients: a randomized, controlled study

OBJECTIVE

Several studies have reported omega-3 and omega-6 fatty acid imbalances in patients with cystic fibrosis (CF). Whether these imbalances contribute to or are manifestations of the pathophysiology of CF is unknown. The study objective was to determine bioavailability, tissue accretion, and safety of a large dose of an algal source of docosahexaenoic acid (DHA) triacylglycerol and to observe effects on lung function in patients with CF.

METHODS

Twenty subjects with CF (8 to 20 y of age) were randomly assigned to receive algal oil providing 50 mg of DHA per kilogram per day (1 to 4.2 g of DHA per subject per day) or placebo for 6 mo. Fatty acids, liver enzymes, and lipid soluble antioxidants were measured in blood at baseline and at 1, 3, and 6 mo. Rectal biopsy specimens were collected at baseline and at 3 mo for fatty acid analysis. Lung function, anthropometrics, and adverse experiences were monitored throughout the study.

RESULTS

Compared with placebo, DHA supplementation increased plasma, erythrocyte, and rectal DHA levels four- to five-fold (P < 0.001) with concomitant decreases in blood arachidonic acid levels and the ratio of arachidonic acid to DHA. Supplementation was well tolerated, with no treatment-related changes in liver enzymes, growth, or antioxidant status. DHA supplementation had no detectable effect on lung function during the course of this study.

CONCLUSIONS

Algal DHA triacylglycerol oil is readily absorbed, well tolerated, and increases blood and tissue DHA levels in patients with CF. No adverse developments were associated with this large dose of DHA oil. Larger studies of longer duration are needed to determine whether DHA supplementation results in any clinically significant benefits in patients with CF.

Longitudinal study of oxidative status in 312 cystic fibrosis patients in stable state and during bronchial exacerbation

In cystic fibrosis (CF), there is an imbalance in the oxidant/antioxidant system, leading to oxidative damage. The aim of this study was to assess antioxidant-scavenger deficiencies and lipid peroxide variations in three clinical situations (stable status, acute exacerbation, and after intravenous antibiotic treatment). The objective was also to correlate oxidative stress with age, nutritional status, and respiratory function. The study included prospectively 312 consecutive patients and 53 controls. Antioxidants (vitamin A, vitamin E, carotenoids, and glutathione) and oxidative markers (malondialdehyde and lipid peroxides) were measured in plasma. Regression analyses were performed. Antioxidant levels were lower in CF patients than in controls. These levels decreased during acute exacerbation and increased after antibiotic treatment. Carotenoid levels were not modified by infection or age. Only vitamin A and carotenoid levels were positively correlated to body mass index. Antioxidant levels were correlated to forced expiratory volume at 1 sec. Lipid peroxidation markers were lower in patients than in controls. Their levels decreased during infection, and increased after antibiotic treatment. Impaired lung function was correlated with elevated malondialdehyde levels. In conclusion, this study demonstrates antioxidant deficiency in a very large cohort of CF patients. Carotenoid and vitamin E deficiencies occur early in the course of the disease. Antioxidants decrease with bronchial infection. By contrast, nutritional disorders did not modify antioxidant levels during acute exacerbations. Thus, pulmonary disorders rather than nutritional disorders seem to be essential in the imbalance of the oxidant/antioxidant system. Results concerning glutathione and oxidative-marker levels highlighted the fact that their plasma values do not reflect oxidative stress in the respiratory tract.

Nutritional abnormalities contributing to cachexia in chronic illness

Cachexia is a common consequence of chronic illness. The nutritional abnormalities contributing to the clinical picture are often a composite of reduced appetite, dietary factors including protein, energy and micronutrient intake, malabsorption and increased consumption or loss of nutrients. In this article, using chronic heart failure as an example, we have reviewed the potential influences of chronic disease on each of these and how they might lead to the relentless progression of wasting and the poor prognosis associated with it.