Dietary and circulating polyunsaturated fatty acids in cystic fibrosis: are they related to clinical outcomes?

Objective: To assess the relationship between dietary intakes, plasma phospholipid (PL) fatty acid profile and clinical parameters in children with cystic fibrosis (CF) in comparison to healthy controls. Patients and Methods: A cross-sectional survey including 37 patients with CF (ages 8.0 ± 2.9 yrs) and a reference group of 68 healthy children (ages 8.0 ± 0.7 yrs) was carried out by means of a food-frequency questionnaire. At enrolment, all subjects underwent blood sampling for plasma PL fatty acids (FA). In CF patients, pulmonary function tests (forced expiratory volume in 1 second and forced vital capacity), anthropometric measurements and the Shwachman score were also determined. Results: In CF patients, mean z score for weight and height (-0.35 ± 1.16 and -0.28 ± 0.99) were lower than controls (0.83 ± 1.73 and 0.55 ± 1.11, respectively). Patients with CF showed higher energy intakes (110 ± 43 kcal/d) compared with controls (75 ± 22 kcal/d; P<0.0001), with higher intake of total (saturated and monounsaturated) fats and lower intake of polyunsaturated FA (3.9 ± 1.0% of total macronutrient intake vs 4.3 ± 1.2%, P = 0.05). In CF patients, plasma and PL levels of linoleic and docosahexaenoic acids were lower, whereas those of arachidonic acid were similar compared with controls. The Shwachman score showed significant positive associations with plasma PL levels of arachidonic acid and total n-6 long-chain FA (r=0.32, P=0.05, and r=0.35, P=0.03, respectively). Conclusions: The data give suggestions that fat intake and CF-associated biomechanisms are bound in a vicious circle, concurring to create the clinical and biochemical picture of CF. The quantity and quality of fat supplementation in CF need careful attention to balance the fat supply with polyunsaturated FA.