Sufficient vitamin D status positively modified ventilatory function in asthmatic children following a Mediterranean diet enriched with fatty fish intervention study.

Asthma in children is the most prevalent allergic disease worldwide that has become a major public health priority. The objective of this study was to examine the relationship between baseline serum vitamin D status, spirometry, and fractional exhaled nitric oxide levels (FeNO) in 64 Greek children with 'mild asthma' aged 5 to 12 years (51.6% male) in a dietary intervention study. We hypothesized that baseline serum vitamin D levels modify the beneficial response of fatty fish intake on pulmonary function in asthmatic children following a Mediterranean diet. The intervention group consumed 2 fatty fish meals/week (≥150 g cooked filleted fish/meal) as part of the Mediterranean diet for six months, and the control group consumed their usual diet. Baseline serum 25(OH)D was determined using enzyme-linked immunoassay and defined as sufficient levels of 25(OH)D ≥25 ng/mL. Only 36% of children were graded as sufficient in 25(OH)D levels on entry into the study with a higher proportion of girls insufficient than boys (61% vs 39% respectively). Participants with sufficient levels of serum 25(OH)D at baseline, consuming the intervention diet increased FEV1/FVC by 4.89 units (ß = 4.89; 95%CI: 1.19-8.61; p = 0.013) and FEF25-75% by 12.83 units (ß = 12.83; 95%CI: 4.27-21.40; p = 0.006) compared to controls. No significant differences in pulmonary function or FeNO were observed for those with insufficient levels of 25(OH) D in the intervention or control groups. In conclusion, sufficient serum vitamin D levels enhanced ventilatory function in response to a dietary intervention in asthmatic children.

Does adherence to the Mediterranean dietary pattern reduce asthma symptoms in children? A systematic review of observational studies.

OBJECTIVE: The purpose of the present systematic review was to synthesize evidence from the literature to assess efficacy of the Mediterranean dietary pattern in childhood asthma. Design/Setting A systematic search of six databases, three clinical trial registries and hand-search of peer-reviewed articles was conducted up to 29 October 2016. Inclusion criteria included exposure to a Mediterranean dietary pattern, measurement of asthma symptoms and study population of children aged <18 years. Quality assessment was conducted. Due to significant heterogeneity, meta-analysis was not feasible. RESULTS: Of the 436 articles identified, after removal of duplicates and based on inclusion criteria, fifteen observational studies conducted in Mediterranean and non-Mediterranean countries were relevant. No randomized controlled trials were retrieved. Twelve studies reported an inverse association between adherence to a Mediterranean dietary pattern and asthma in children, two studies showed no association and one study showed an increase in asthma symptoms. In fourteen out of fifteen studies, quality assessment checks revealed good reliability and validity among study methodologies. CONCLUSIONS: The current systematic review revealed a consistent inverse relationship (protective) between a Mediterranean dietary pattern and asthma in children. Future well-designed randomized controlled trials are needed to provide solid evidence. Nevertheless, the existing level of evidence adds to the public health message relating to the beneficial effects of a Mediterranean-type diet in children suffering with asthma.