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Polyunsaturated fatty acids in school children in relation to allergy and serum IgE levels
1Department of Health and Environment, Linköping University, Sweden. guo.yu@kfc.liu.se
Insights
Allergic children have lower levels of beneficial omega-3 fatty acids like DHA and higher omega-6 to omega-3 ratios. This study suggests a disturbance in long-chain polyunsaturated fatty acid metabolism, not impaired delta-6-desaturase activity, is linked to allergies.
Area of Science:
- Biochemistry
- Immunology
- Pediatrics
Background:
- Altered polyunsaturated fatty acid (PUFA) composition is noted in allergic individuals.
- Impaired delta-6-desaturase activity has been proposed as a cause for these alterations.
Purpose of the Study:
- To investigate PUFA composition in serum phospholipids of allergic children.
- To explore the relationship between PUFA levels and allergic conditions like asthma and dermatitis.
Main Methods:
- Serum phospholipid PUFA composition was analyzed in 22 allergic children (12-15 years) and 23 non-atopic controls.
- Statistical analysis compared fatty acid levels and ratios between allergic and control groups.
- Correlations between fatty acids and IgE levels were examined.
Main Results:
- Allergic children showed lower docosahexaenoic acid (DHA) and total n-3 long-chain polyunsaturated fatty acids (LCP).
- A higher ratio of total n-6 to n-3 LCP was observed in allergic children.
- Correlations between various LCPs, present in non-allergic children, were largely absent in allergic children.
Conclusions:
- The study did not confirm impaired delta-6-desaturase activity in allergic children.
- Findings suggest a disturbance in LCP metabolism is associated with allergic diseases.
- Specific fatty acid profiles may serve as biomarkers for allergic conditions.
Abstract:
Altered composition of polyunsaturated fatty acids (PUFA) has been observed in allergic individuals and it has been proposed that this is due to an impairment of delta-6-desaturase activity. We have studied the composition of PUFA in serum phospholipids in twenty-two 12-15 year old children with asthma and/or allergic dermatitis and 23 non-atopic controls of similar age. The relative levels of docosahexaenoic acid (DHA, C22:6n-3) and total n-3 long-chain polyunsaturated fatty acids (LCP) were lower (1.46% +/- 0.54 vs. 1.90% +/- 0.58, P = 0.01 for DHA and 2.34% +/- 0.67 vs. 2.80% +/- 0.77, P < 0.05 for total n-3 LCP) and the ratio of total n-6 to n-3 LCP was higher (P < 0.01) in the allergic children than in the controls. In addition to these differences, the relative levels of docosapentaenoic acid (DPA, C22:5n-3) and the ratio of arachidonic acid (AA, C20:4n-6) to dihomo-gamma-linolenic acid (DHGLA, C20:3n-6) were also lower in the 12 allergic children with positive skin prick test, as compared with the SPT negative children (both P < 0.05). In non-allergic children, the levels of total n-3 correlated with n-6 LCP (r = 0.76, p < 0.001). Furthermore, the n-3 LCP, i.e. EPA, DPA and DHA, correlated significantly with each other (r = 0.52-0.78, all p < 0.01) and correlated with n-6 LCP, i.e. C20:2, DHGLA and AA respectively (r = 0.56-0.83, all P < 0.01). Most of these correlations were absent in allergic children. Higher levels of C20:2n-6 and lower levels of eicosapentaenoic acid (EPA, C20:5n-3) were recorded in 11 allergic children with serum IgE above the median level (56 kU/l), as compared to 11 with lower IgE levels (both P < 0.05). Furthermore, the levels of C20:2n-6 correlated with the IgE levels in the children (r = 0.65, P = 0.001). The findings could not confirm an impaired delta-6-desaturase activity in allergic school children and suggest that a disturbance of LCP metabolism is associated with allergic diseases.