Dietary intake in patients with asthma: A case control study

Objective This case-controlled study investigated differences in dietary intake between a population with and without asthma. Methods A case-controlled study of the dietary intakes of subjects with asthma (n = 54, average age 23.59 ± 9.6 y; group 1) and healthy subjects (n = 54, average age 27.07 ± 7.2 y; group 2) using 3-d dietary intakes was undertaken. Fifty-four patients with asthma and healthy non-asthmatic subjects matched by age and sex were selected. All enrolled subjects (asthmatic and non-asthmatic) received instruction to record their daily dietary intake for 3 d including a weekend day. Pulmonary function tests were performed in asthmatic patients Results Total energy intake and distribution of energy were normal in both groups (39.7% carbohydrates in group 1 and 41% in group 2, 19.4% proteins in group 1 and 22% in group 2, and 40.9% lipids in group 1 and 37% in group 2). A higher intake of vitamin A (642 ± 399 μg/d) was detected in non-asthmatic than in asthmatic subjects (459 ± 242 μg/d, P < 0.05). Daily intake of vitamin C was higher in non-asthmatic subjects (124 ± 70 mg) than in asthmatic subjects (93.1 ± 63.9 mg, P < 0.05). Vitamin E intake was higher in non-asthmatic subjects (7.3 ± 1.2 mg) than in asthmatic subjects (5.1 ± 2.3 mg, P < 0.05). Correlation analysis between daily intake and forced expiratory volume in 1 s (FEV1) in group 1 (asthmatic subjects) showed a positive association between ω-3 fatty acids (g/d) and FEV1 (r = 0.6, P < 0.05). No statistical correlations were detected between ω-6 and ω-9 fatty acid intakes and FEV1. Multivariant analysis with the dependent variable of FEV1 showed that only vitamin C and ω-3 fatty acids remained in the model after adjusting for smoking, age, and sex (F = 14.24, P < 0.001), with an increase of 0.25% (95% confidence interval = 0.1–0.4) in FEV1 with each 1 μg of vitamin C intake and an increase of 99.3% (95% confidence interval = 81.59–137.19) in FEV1 with each 1 g of ω-3 fatty acids. Conclusions Asthmatic patients have a lower intake of vitamins A, C, and E than do non-asthmatic subjects. Intake of ω-3 fatty acids was correlated with FEV1.