BACKGROUND: Supplementation with long-chain n-3 polyunsaturated fatty acids (LCPUFAs) has been found to reduce the development of allergic disease.
OBJECTIVE: The aim of this study was to compare the effectiveness of fish oil diets rich in eicosapentaenoic acid (20:5n-3; EPA) or docosahexaenoic acid (22:6n-3; DHA) in suppressing food allergic symptoms.
METHODS: Mice were fed a control diet (10% soybean oil) or fish oil diet rich in EPA (4% soybean oil + 6% EPA oil containing 28.8% EPA and 13.7% DHA) or DHA (4% soybean oil + 6% DHA oil containing 7% EPA and 27.8% DHA), starting 14 d before and for 5 wk during oral sensitization with peanut extract (PE) or whey. Acute allergic skin responses, serum immunoglobulins (Igs), and mucosal mast cell protease-1 (mmcp-1) were assessed. Hyperimmune serum was transferred to naive recipient mice fed the different diets.
RESULTS: The DHA diet effectively reduced the acute allergic skin response compared with the control or EPA diet in PE-allergic mice (control, 159 ± 15, or EPA, 129 ± 8, vs. DHA, 78 ± 7 μm; P < 0.0001 or P < 0.05, respectively). In contrast, both the DHA and EPA diets reduced the allergic skin response in whey allergic mice (control, 169 ± 9, vs. DHA, 91 ± 13, or EPA, 106 ± 14 μm; P < 0.001 or P < 0.01, respectively); however, only the DHA diet reduced mmcp-1 and whey-specific IgE and IgG1. The DHA and EPA diets also reduced the acute skin response in passively immunized mice.
CONCLUSIONS: The DHA-rich fish oil diet reduced allergic sensitization to whey and allergic symptoms in both PE- and whey-allergic mice. These data suggest that DHA-rich fish oil is useful as an intervention to prevent or treat food allergy symptoms.