The Relationship Between The Level Of Polyunsaturated Fatty Acid In Maternal Breast Milk And FADS2 Gene Variants

Objective:The exclusive breastfeeding infants’ development depends on the nutrition of maternal breast milk. The polyunsaturated fatty acids(PUFAs) is important for the health of maternal and infant. The diet and gene variants are the two factors to determine the levels of PUFAs in maternal breast milk. We investigated the the levels of PUFAs in maternal dietary intake and breast milk, and to build the information of FADS2 gene variants. Then, the effect of the PUFAs in diet and FADS2 gene variants on the levels of PUFAs in breast milk of Chinese North Han ethnic maternal will be observed. Methods:We screened all pregnant women registered for postpartum care in Changchun from March 2012 to December 2014. According to the criteria of inclusion and exclusion, 209 Han ethnic maternal without the use of PUFAs-containing supplements during pregnancy and lactation were included. Informed consent and a 24-hour dietary recall questionnaire was implemented preceding milk collection through face to face method, and 20 m L of mature breast milk was collected. Dietary PUFAs intakes were calculated according to Chinese food composition in 2009 and the 24-hour dietary recall questionnaire. The fatty acid methyl esters(FAME) of 10 m L breast milk was extracted and gas chromatography was used to determine the levels of FAME. Then, the concentration of 8 kinds of PUFAs were calculated according to the corresponding conversion coefficient in the national standard. The another 10 m L milk was used to DNA extraction. The SNPs rs3834458, rs1535, rs174575, rs174602 and rs498793 were chosen as the test loci. Genotyping was performed using the Sequenom Mass Array system. At last, the data were entered into the base and analyzed. The basic information, the levels of PUFAs intake, the concentration of PUFAs in breast milk were described, and the relationship between the PUFAs of dietary intake and breast milk, and the effect of single SNP on the PUFAs in breast milk were analyzed, through the SPSS statistics software version 20.0. The linkage disequilibrium was estimated by Haploview software 4.2. The analysis of the association of haplotype and PUFAs in breast milk was performed by the Unphased software 3.012. All statistical tests were two-tailed and the threshold for statistical significance was set at ≤0.05. Results:1. The 209 healthy lactating mothers included in this study had an average age of(30.00±4.00) years. The maternal education degree were 8.6% postgraduate or higher education, 50.2% undergraduate and 35.4% high school or below education. The percent of fathers were 10%, 38.8% and 32.1%, respectively. 54.5% of subjects breastfed exclusively while the remaining 43.1% opted for mixed feeding.2. The maternal daily dietary intake of LA, ALA, AA, EPA and DHA were 20.95 g, 3.16 g, 17.50 mg, 39.95 mg and 17.10 mg respectively.3. The genotype distributions of rs3834458、rs1535、rs174575、rs174602 and rs498793 were in Hardy-Weinberg equilibrium(P>0.05) in all maternal. The minor allele frequency of the 5 SNPs were 29.76%、29.57%、9.8%、22.57% and 8.3%, respectively.4. The level of LA secreted by maternal was lower than the adequate intake(AI) of 0~6 month infants. And, the levels of AA, ALA and DHA were above AI.5. Liner regression result showed the negative association between the dietary EPA and the milk LA(R2=0.028,P=0.023), and the negative association between the dietary LA and the milk DGLA(R2=0.024,P=0.034). The association among other PUFAs were not observed(P>0.05). After the adjustment of maternal age and prepregnant BMI, the dietary EPA and the milk LA, the dietary LA and the milk DGLA were still negatively associated(R2=0.023,P=0.022;R2=0.020,P=0.031).6. After adjusting the maternal age and prepregnant BMI, and regarding the major allele homozygote as reference, rs174575 heterozygote(CG) was associated with lower level of ALA(P=0.037), however, rs498793 minor allele homozygote(AA) was associated with lower level of ALA(P=0.049); maternal with rs1535 minor allele homozygote(GG) has lower GLA level(P=0.013); rs3834458 minor allele homozygote(del.del), rs1535 minor allele homozygote(GG), rs174602 heterozygote(AG) and rs498793 minor allele homozygote(AA) were all associated with levels of AA(P=0.046,P=0.014,P=0.048,P=0.050).7. Haploview analysis result showed that the rs3834458, rs1535, amd rs174575 were in the disquilibrium block(D’>0.9, R2>0.9). The haplotype rs3834458(del.)-rs1535(G), rs1535(G)-rs174575(A), rs3834458(del.)- rs174575(A) amd rs3834458(del.)- rs1535(G)-rs174575(A) were associated with lower levels of GLA amd AA(P<0.05). Conclusion:1. Maternal intake of LA and ALA were above AI. The intake of EPA and DHA were lower than AI.2. The concentration of LA in breast milk was lower, and the concentration of ALA, AA, DHA were all higher than AI of 0~6-month infants.3. The level of GLA in breast milk was associated with rs1535 gene variant; the level of AA were associated with the gene variants of rs3834458、rs1535、rs174602 and rs498793; the level of ALA was associated with the gene variants of rs174575 and rs498793.4. The levels of GLA and AA were associated with the haplotypes, included rs3834458-rs1535 、 rs1535-rs174575 、 rs3834458-rs174575 �'� rs3834458-rs1535-rs174575.