Abstract
BackgroundEvidence suggests that prenatal exposure to n-3 long-chain polyunsaturated fatty acids (LCPUFA) reduces the incidence of allergic disease in children. LCPUFAs are produced from dietary precursors catalyzed by desaturases and elongases encoded by the FADS1/2 and ELOVL5 genes. DNA methylation regulates gene activity and fatty acid supplementation could alter DNA methylation (DNA-M) at these genes. We investigated whether DNA-M and expression of the FADS1/2 and ELOVL5 genes were associated with allergy in children and gestational fish intake. We studied 170 participants from the Isle of Wight 3rd Generation Cohort, UK. Phenotype data and exposure was assessed by questionnaires. Genome-wide DNA-M in cord blood samples was quantified using the Illumina Infinium HumanMethylation450 and EPIC Beadchips. Five SNPs (single-nucleotide polymorphisms) in the FADS gene cluster and one SNP in ELOVL5 were genotyped in offspring. FADS gene expression in offspring cord blood was determined.ResultsGestational fish intake was significantly associated with increased methylation of cg12517394 (P = 0.049), which positively correlated with FADS1 mRNA levels (P = 0.021). ELOVL5 rs2397142 was significantly associated with eczema (P = 0.011) and methylation at cg11748354 and cg24524396 (P < 0.001 and P = 0.036, respectively). Gestational fish intake was strongly associated with elevated DNA-M at cg11748354 and cg24524396 (P = 0.029 and P = 0.002, respectively) and reduced ELOVL5 mRNA expression (P = 0.028).ConclusionThe association between induced FADS1/2 and ELOVL5 DNA-M and reduced gene expression due to gestational fish intake provide a mechanistic explanation of the previously observed association between maternal LCPUFA intake and allergy development in early childhood.
Highlights
Evidence suggests that prenatal exposure to n-3 long-chain polyunsaturated fatty acids (LCPUFA) reduces the incidence of allergic disease in children
There were no substantial differences in the prevalence of maternal smoking during pregnancy, maternal history of asthma, maternal history of eczema, maternal socioeconomic status, child eczema, child wheeze, and maternal oily fish intake between the total cohort and those who were randomly selected for the DNA-methylation analysis (Table 1)
This study investigated the effects of oily fish intake during the third trimester of pregnancy on the allergic outcomes of the infants by using a subset of umbilical cord blood samples from Isle of Wight (IoW) F2 generation
Summary
Evidence suggests that prenatal exposure to n-3 long-chain polyunsaturated fatty acids (LCPUFA) reduces the incidence of allergic disease in children. We investigated whether DNA-M and expression of the FADS1/2 and ELOVL5 genes were associated with allergy in children and gestational fish intake. Exposure to omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) during pregnancy has been found to be associated with allergic outcomes in infants or children [3]. A recent large prospective study could not substantiate the previously observed beneficial association between fish and seafood consumption in pregnancy and development of asthma and allergic rhinitis symptoms in children up to 8 years of age [10]. A metaanalysis of six studies revealed an association between fish oil supplementation during pregnancy and reduced risk of sensitization to food allergens at first year [11]
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