Dietary supplementation with fish oil rich in omega-3 polyunsaturated fatty acids in children with bronchial asthma. Effect of dietary intake of omega-3 and omega-6 fatty acids on severity of asthma in children. Effect of dietary supplementation with fish oil lipids on mild asthma. Effect of a fish oil diet on asthma: results of a 1-year double-blind study. Evening primose oil and fish oil are ineffective as supplementary treatment of bronchial asthma. The effects of dietary supplementation with fish oil lipids on the airways response to inhaled allergen in bronchial asthma. Dietary fish oil effects on seasonal hay fever and asthma in pollen-sensitive subjects.
Omega-3 polyunsaturated fatty acids have anti-inflammatory effects in vitro, and high dietary levels are associated with a lower incidence of inflammatory diseases. However, only limited effects have been demonstrated in asthma. The effects of dietary supplementation with fish oil for 10 months in 29 children with bronchial asthma was investigated in a randomized controlled fashion. In order to minimize the effects of environmental inhaled allergens and diet, this study was performed in a long-term treatment hospital. Subjects received fish oil capsules containing 84 mg eicosapentaenoic acid (EPA) and 36 mg docosahexaenoic acid (DHA) or control capsules containing 300 mg olive oil. The daily dosages of EPA and DHA were 17.0-26.8 and 7.3-11.5 mg x kg body weight(-1), respectively. Asthma symptom scores decreased and responsiveness to acetylcholine decreased in the fish oil group but not in the control group. In addition, plasma EPA levels increased significantly only in the fish oil group (p<0.0088). No significant side-effects were observed. The present results suggest that dietary supplementation with fish oil rich in the omega-3 polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid is beneficial for children with bronchial asthma in a strictly controlled environment in terms of inhalant allergens and diet. We assessed the clinical and biochemical effects in asthmatic children of fish oil supplementation and a diet that increases omega-3 and reduces omega-6 fatty acids. Thirty nine asthmatic children aged 8-12 yrs participated in a double-blind, randomized, controlled trial for 6 months during which they received fish oil capsules plus canola oil and margarine (omega-3 group) or safflower oil capsules plus sunflower oil and margarine (omega-6 group). Plasma fatty acids, stimulated tumour necrosis factor alpha (TNFalpha) production, circulating eosinophil numbers and lung function were measured at baseline and after 3 and 6 months of dietary modification. Day and night symptoms, peak flow rates and medication use were recorded for 1 week prior to laboratory visits. Plasma phospholipid omega-3 fatty acids were significantly greater in the omega-3 group at 3 and 6 months compared to the omega-6 group (p<0.001). In the omega-3 group TNFalpha production fell significantly compared with baseline (p=0.026), but the magnitude of change between groups did not reach significance (p=0.075). There were no significant changes in clinical outcome measures. Dietary enrichment of omega-3 fatty acids over 6 months increased plasma levels of these fatty acids, reduced stimulated tumour necrosis factor alpha production, but had no effect on the clinical severity of asthma in these children. Recruitment of inflammatory leucocytes to the airways may play a part in the pathogenesis of asthma. As dietary enrichment with fish oil lipids can suppress leucocyte function, the effect of these lipids on asthma control and neutrophil function was studied in 20 subjects with mild asthma. Twelve subjects received capsules containing 3.2 g of eicosapentaenoic acid and 2.2 g of docosahexaenoic acid daily and eight subjects received placebo capsules containing olive oil for 10 weeks in a double blind fashion. Baseline specific airways conductance, airways responsiveness to histamine and exercise, diurnal peak expiratory flow, symptom scores, and bronchodilator use were measured. Neutrophil fatty acid composition was evaluated by gas chromatography, calcium ionophore induced neutrophil leukotriene (LT)B4 and LTB5 generation were measured by reverse phase high performance liquid chromatography and radioimmunoassay, and neutrophil chemotactic responses to formyl-methionyl-leucyl-phenylalanine (FMLP) and LTB4 were assessed by a microchemotaxis technique. Although the fish oil supplemented diet produced a greater than 10 fold increase in the eicosapentaenoic acid content of neutrophil phospholipids, there was no significant change in airways responsiveness to histamine or any change in any of the clinical measurements. After dietary supplementation with fish oil there was a 50% inhibition of total LTB (LTB4 + LTB5) generation by ionophore stimulated neutrophils and neutrophil chemotaxis was substantially suppressed. Neutrophil function remained unchanged in the placebo group. It is concluded that in subjects with mild asthma a fish oil enriched diet attenuates neutrophil function without changing the severity of asthma. Airway inflammation is a major component of asthma. Food intake of N-3 fatty acids (FA) is associated with a low incidence of inflammatory diseases, such as asthma. We treated 12 asthmatic patients with FA and report the positive results of this 1-year double-blind study. A positive effect on forced expiratory volume in 1 s was observed after the 9 month of treatment. Our results are in favor of the use of FA, but have to be confirmed by other studies. The effect of daily dietary supplementation with 15 to 20 mL of evening primrose seed oil or fish oil was assessed by comparison with olive oil as placebo in a cross-over study in 29 asthmatics. During 10 weeks of each regimen, the patients kept record of symptoms, peak expiratory flow rates and medication. Plasma and urine TxB2, PGE2, PGF2 alpha and 6 keto-PGF1 alpha and plasma fatty acid composition of plasma cholesterol esters were measured at the end of each treatment period. There were no differences between regimes with regard to peak flow rates, symptoms, or drug consumption. Plasma PGE2 levels increased during the fish oil treatment but there were no changes in other prostanoids in plasma or urine. The fatty acid pattern of plasma cholesterol esters showed significant differences between the supplementation periods. We conclude that moderate doses of evening primrose oil or fish oil are ineffective as a supplementary treatment of bronchial asthma. The effects of dietary supplementation with fish oil lipids on the airways responses to allergen and neutrophil biochemistry and function have been studied in 17 atopic asthmatic subjects. Nine subjects received 18 capsules of Max-EPA (3.2 g eicosapentaenoic acid and 2.2 g docosahexaenoic acid) a day and eight subjects received identical capsules containing olive oil, for 10 wk in a double-blind fashion. There were no differences between prediet values and those observed after dietary supplementation with Max-EPA or placebo in the dose of allergen causing an acute asthmatic response as assessed by a 35% fall in specific airways conductance (PD35), the extinction dose of allergen on skin prick testing, the histamine PD35, or the total serum IgE concentrations. Twelve of the 17 subjects developed late asthmatic responses after allergen challenge prediet. Six of these subjects received Max-EPA, and six received placebo capsules. As compared to prediet values, the magnitude of the allergen-induced late asthmatic response was significantly attenuated from 2 to 7 h after allergen challenge following dietary supplementation with Max-EPA (p less than 0.005) but not with placebo. The attenuation of the late response was not accompanied by any significant change in the clinical severity of disease as assessed by diurnal peak expiratory flow rates, symptom scores, or bronchodilator drug usage.(ABSTRACT TRUNCATED AT 250 WORDS) The effects of taking 18 capsules a day of Max-EPA (3.2 g/day eicosapentaenoic acid) on clinical symptoms and bronchial hyperresponsiveness were studied in pollen-sensitive subjects over a pollen season in a parallel, double-blind, placebo-controlled (olive oil) fashion. The study was conducted over the 1990 and 1991 pollen seasons in London, England. A total of 37 nonsmoking pollen-sensitive asthmatic subjects were entered into the trial, and 25 completed the 6-month study period over the 2 yr. The preseasonal geometric mean PD35 SGaw of histamine for the fish oil (n = 12) and placebo (n = 9) groups were 0.62 and 0.42 mumol, respectively. During the middle of the pollen season, histamine PD35 SGaw fell significantly for both the fish oil (0.11 mumol, p < 0.0001) and placebo groups (0.10 mumol, p < 0.007), indicating increased bronchial reactivity compared with preseasonal values, but there was no significant difference between the groups. Similarly, morning and evening peak expiratory flow (PEF), diurnal variability in PEF, nocturnal cough and wheeze, daytime wheeze, and activity, as well as nasal symptoms and increased usage of medication, were not significantly different between the groups. Compliance was confirmed by neutrophil and plasma phospholipid analysis, which showed significant rises in eicosapentaenoic acid content in the fish oil group but not in the placebo group. We conclude that dietary fish oil supplementation does not prevent seasonal hay fever and asthma in pollen-sensitive subjects during the pollen season.
There is little evidence to recommend that people with asthma supplement or modify their dietary intake of marine n-3 fatty acids (fish oil) in order to improve their asthma control. Equally, there is no evidence that they are at risk if they do so.