The Effects Of FADS Gene Cluster And Maternal Diet On The Composition Of Fatty Acids In Breast Milk And Its Mechanism

Breast milk is also known as "white blood".The healthy and nutritious milk is a rich in various nutrients and considered the most ideal food source to ensure the healthy growth and development of babies.Fats and fatty acids are considered one of the important compounds that provide energy and nutrition for infants.Fatty acids in milk are the main source that promotes the development of the central nervous system in infants,especially polyunsaturated fatty acids,which have been used in infant growth and development.The amount of fatty acid in breast milk may be affected by the diet and genes of the lactating mother.For the inland lactating mothers who consume fish rarely,the effect of the FADS gene which encodes the ?-5 and ?-6 desaturase in the PUFA transformation in vivo may be more prominent.But the effects of FADS gene mutations on fatty acid status and many functional SNPs in the FADS gene cluster have not been identified,and no studies have been reported the association between FADS gene expression and fatty acids in breast milk.Studies on the effect of diet on breast milk fatty acids focus on a single diet and supplement intake.Lactating mothers do not consume only one nutrient or food in their daily diets,but take in large amounts of nutrients from various types of food and have specific dietary patterns.Little research has been carried out on dietary patterns and compositional profiles of milk FA.The current study composed of lactating women in Changchun and explored the relationship between the SNP of FADS gene cluster and the level of PUFA in breast milk.The dietary pattern was used to explore the relationship between dietary intake and breast milk FA.A system for detecting FADS gene expression in breast milk was established.The differences in PUFA levels of breast milk in different FADS gene expression groups were analyzed.The current study included the following three parts:Part?: FADS gene cluster and fatty acids of breast milk Objective:To determine the relationship between rs174547,rs174553,rs174602,rs3834458 and rs1000778 loci in the FADS gene cluster and PUFA levels in breast milk.Methods:A total of 420 postpartum 22-25 day lactating women were collected from postpartum care center in Changchun from March 2012 to December 2014.Informed consent was obtained and a comprehensive questionnaire and adequate breast milk were provided.Gas chromatography was used to detect the levels of eight PUFAs in breast milk,and DNA was extracted from breast milk and used the Sequenom MassArray system to perform five SNP typing on the FADS gene cluster.The basic information of the subjects and the eight PUFA levels in breast milk were analyzed by SPSS24.0 software.The relationship between the five SNPs of FADS gene and the PUFA level of milk was analyzed by SNPstats online analysis software.Result:1.The levels of LA,ALA,DGLA,EPA,DTA,and DHA in breast milk were correlated with age(P<0.05).The levels of LA,ALA,DGLA,and DTA were associated with maternal postpartum BMI(P<0.05).No PUFA levels were found correlation with dietary source PUFA(P>0.05).2.The lowest detection rate of the five loci included in the study was rs174547(96.19%),the detection rate of other loci was above 97%;the minimum P value of Hardy-Weinberg test was 0.30,which was consistent with Hardy-Weinberg genetic balance.3.There were no differences in LA,ALA,and DHA levels in breast milk and in different genetic model groups at each SNP(P>0.05).4.The levels of GLA and AA in breast milk were related to rs174547 loci,rs174553 loci of FADS1 gene,rs3834458 loci and rs174602 loci of FADS2 gene;the optimal model of rs174547,rs174553 and rs3834458 loci was codominant model,while the optimal genetic model of rs174602 loci is dominant model.5.The level of DGLA in breast milk is related to rs174547 loci of FADS1 gene and rs3834458 loci of FADS2 gene;the optimal genetic model of the former is dominant model,and the optimal genetic mode of the latter is recessive model.6.The level of breast milk EPA is related to rs174547,rs174602,and rs3834458 loci and the optimal inheritance model of these three SNP is dominant model.EPA is also related to rs1000778 loci of FADS3 gene,and the optimal inheritance model is recessive model.7.The level of DTA in breast milk is related to rs174547,rs174553,and rs3834458 loci.The optimal model of these three SNP loci is recessive model.Conclusion:1.The level of PUFA in breast milk is related to the age of the lactating mother and the postpartum BMI and has nothing to do with the PUFA in the diet.2.The levels of GLA,DGLA,AA and DTA in breast milk are related to FADS1 and FADS2 gene variants.The level of EPA in breast milk is related to the variation of FADS1,FADS2 and FADS3 genes.Part?: Dietary patterns and fatty acids of breast milk Objective:To study the relationship between dietary patterns and the composition of breast milk FA in lactating mothers.And that provides a scientific basis for a reasonable diet and better feeding of babies in lactating women.Method:Using a cross-sectional survey,from January 2015 to June 2017,274 Han Chinese lactating women from 22 to 6 months postpartum were recruited from Changchun City and questionnaires and milk were collected.The composition of FA in breast milk was determined,and the dietary condition of the subjects was divided into different dietary patterns using principal component analysis.The SPSS24.0 statistical software was used to analyze the differences in the composition of the diet and milk FA of the lactating mothers in different dietary patterns.Result:1.The average daily energy intake of lactating women included in this study was 1774.36 kcal,accounting for 77.15% of the recommended intake;the average intake of carbohydrates was 233.76 g/d,the average intake of protein was 67.38 g/d,the average intake of fat was 66.65 g/d,accounting for 70.70%,84.22% and 104.31% of the recommended intake,respectively.2.The study was divided into four dietary patterns.Lactating women with X dietary Pattern 1 mainly ate mushrooms and algae,meat,and marine products;those with Pattern 2 mainly ate soybean products,nuts,and dairy products;Pattern 3 mothers mainly ate fruits and vegetables;and Pattern 4 mothers mainly ate grains,potatoes and beans as well as eggs.3.In different dietary patterns,the average daily intake of energy,carbohydrates,and protein in the lactating mothers and their ratios to their recommended amounts were statistically significant(P=0.014,P=0.004,P=0.002);the daily fat intake and ratio of the lactating mothers were not statistically significant(P=0.556).4.The daily intake of calcium,iron,zinc,copper and magnesium in the lactating mothers were statistically different among the patterns(P<0.001,P<0.001,P=0.021,P<0.001,P=0.012);vitamin A,vitamin B1,vitamins B2,niacin,and folic acid intake were statistically significant(P=0.011,P=0.045,P=0.004,P=0.003,P=0.029),while vitamin C and vitamin E did not show differences.5.The total proportion of SFA and PUFA in breast milk was statistically different among different patterns(P<0.001,P=0.025),and the proportion of n-6 PUFA also showed statistical significance(P=0.038);MUFA,n-3 PUFA and n-6/n-3 were not found to be statistically significant among the four dietary patterns(P>0.05).6.In the SFA of breast milk,the percentages of C6:0,C10:0,C11:0 and C23:0 were statistically different among four patterns(P=0.038,P=0.008,P=0.003,P<0.001).In MUFA,C15:1(P=0.048),C18:1n9t(P<0.001)and C18:1n9c(P=0.002)showed differences.In PUFA of breast milk,C18:2n6c,C20:2,C20:3n6,C20:4n6 and C22:6n3 showed differences among different dietary patterns(P=0.002,P=0.043,P<0.001,P=0.018,P=0.020).Conclusion:1.The average energy intake,carbohydrates and protein intake are lower than the recommended intake of the 274 lactating mothers,while the average intake of fat is higher than the recommended intake.2.The intake of energy,carbohydrates,protein,minerals and trace elements in lactating mothers varies from different dietary patterns.3.Dietary patterns can affect not only the SFA,PUFA and n-6 PUFA levels in breast milk.Part?: FADS gene expression and fatty acids of breast milk Objective:To explore the difference in PUFA levels of breast milk of different FADS gene expression groups.And provide a scientific basis of the correlation between the levels of PUFA in breast milk and FADS gene expression.Method:The study population consisted of 50 healthy Han women who were recruited for 42-45 days after birth from a maternal and child health care hospital in Changchun from January 2017 to August 2017.The basic information questionnaire and breast milk were collected.Eight kinds of PUFAs in milk were detected.The RNA in milk was extracted by Trizol method.The transcription level of FADS gene in breast milk was detected by real-time quantitative PCR.The total protein in milk was extracted and combined with Western blot experiment to detect the translation level of FADS gene in breast milk.SPSS24.0 statistical software was used to analyze the differences in PUFA levels of breast milk between different FADS gene transcription and translation groups.Result:1.AA accounted for 0.8616% of total FA and the content of DHA was 0.2952% in the breast milk of this study.2.The content of GLA in breast milk was different significantly in the different FADS1 gene transcription groups(P=0.009),and the content of GLA(0.3606%)in the higher level FADS1 gene transcription group was 0.2869% higher than the lower level FADS1 gene transcription group.3.The content of eicosatrienoic acid(C20:3n6)in breast milk was different significantly in the different FADS1 gene transcription groups(P=0.042),and the content of eicosatrienoic acid in the higher level FADS1 gene transcription group(0.5088%)was higher than the lower level FADS1 gene transcription group(0.4363%).4.The content of eicosatrienoic acid(C20:3n3)in breast milk was different significantly in the different FADS1 gene translation groups(P=0.047),and the higher FADS1 gene translation level group mothers had higher eicosatrienoic acid content(0.1132%)than the lower FADS1 gene translation level group(0.0888%)in breast milk.5.The content of EPA in breast milk was different significantly in the different FADS3 gene translation level groups(P=0.040),and mothers in the higher FADS3 gene translation level group had higher EPA content(0.1366%)in breast milk than the lower FADS3 gene translation level group(0.1012 %).6.The content of DHA was different significantly in the different FADS1 gene translation groups(P=0.020),and mothers in the higher FADS1 gene translation level group had higher DHA content(0.3228%)in breast milk than the lower FADS1 gene translation level group(0.2526%).Conclusion:1.The n-6 PUFA in breast milk is related to the transcription level of the FADS gene cluster,that is,the content of GLA and eicosanoid acid(C20:3n6)are related to the transcription level of FADS1 gene.2.The n-3 PUFA in breast milk is related to the translation level of FADS gene cluster,that is,the content of eicosanoid acid(C20:3n3)and DHA are related to the translation level of FADS1 gene,and the content of EPA is related to the translation level of FADS3 gene.