Scientific Papers

Effects of dietary PUFA patterns and FADS genotype on breast milk PUFAs in Chinese lactating mothers | Genes & Nutrition


Subject characteristics

A total of 370 healthy lactating mothers aged 30 years participated in this study. Their monthly family income was divided into 2000 ~ 5000 yuan, 5000 ~ 10,000 yuan, and above 10,000 yuan, accounting for 15.5%, 53.5%, and 31.0%, respectively. Regarding education, 43.8% of the participants had a high school education or below, 46.3% had a bachelor’s degree, and 9.9% had a graduate degree or above. Lactating mothers with normal BMI before pregnancy accounted for 61.3%, gaining 18.5 kg during pregnancy and 39.1 weeks of gestation. The birth weight of the infant was 3.4 kg, and their body length was 50.0 cm. Details are shown in Table 1.

Table 1 Demographic and clinical characteristics of mothers and infants (N = 370)

Dietary fatty acid intake

Supplementary Table 2 showed the comparison between the dietary PUFA intake of the subjects obtained from the dietary frequency questionnaire and their adequate intake (AI), in which the average intake of LA was 18.88 g/d and the average intake of ALA was 1.78 g/d, which was higher than the AI, accounting for 185.10% and 116.34% of the AI separately; the average intake of dietary eicosapentaenoic acid (C20:5n-3, EPA) was 10.82 mg/d, accounting for 21.64% of the AI, and the average intake of dietary DHA was 15.54 mg/d, which was lower than the recommended AI, accounting for only 7.8% of the AI.

Dietary fatty acid pattern

In this study, the dietary fatty acid patterns of 370 subjects were analyzed by PCA. There was a strong linear correlation between the research variables and the data structure was reasonable (KMO test coefficient was 0.69, Bartlett test result was χ2 = 10,414.pc098, P < 0.001), suggesting that the PCA method can be used.

The first three principal component eigenvalues in this study were greater than 1, explaining 45.25%, 18.89%, and 12.23% of the total data variance, respectively, and accurately reflected the dietary fatty acid patterns of lactating mothers. After extraction, the principal components accounted for 76.37% of the total data variation. The rotating component matrix of the dietary fatty acid model outputs the interpretation of the variables for each principal component after extraction. The first principal component mainly included C22:6n-3, C18:4n-3, C20:5n-3, C22:5n-3, and C20:4n-6; therefore, the model dominated by n-3 PUFAs was defined as the n-3 PUFA major pattern. The second main component involved C22:4n-6, C22:3n-3, and C20:3n-6, which was defined as the n-6 PUFAs major pattern. The third principal component mainly involved LA and ALA; therefore, the model dominated by essential PUFAs was defined as the essential PUFA pattern. For each participant, three values for the three different patterns were calculated, and the maximum value represented the dietary fatty acid pattern (Table 2).

Table 2 Rotating component matrix of dietary fatty acid pattern

PUFAs in breast milk

The breast milk fatty acid content of the 370 lactating mothers is shown in Table 3. Average breast milk LA content was 0.378 ± 0.192 (g/100g), average breast milk γ-linoleic acid (GLA) content was 0.038 ± 0.032 (g/100g), average breast milk dihomo-γ-linolenic acid (DGLA) was 0.052 ± 0.040 (g/100g), average breast milk AA was 0.081 ± 0.041 (g/100g), average breast milk DTA was 0.019 ± 0.010 (g/100g), average breast milk ALA was 0.146 ± 0.076 (g/100g), average breast milk EPA was 0.008 ± 0.007 (g/100g), and average breast milk DHA was 0.049 ± 0.035 (g/100g).

Table 3 The levels of PUFA in breast milk of 370 lactating mothers (g/100g)

Characteristics of SNP

Ten SNPs were identified in the present study. Table 4 lists the specific characteristics of the ten candidate SNPs in the FADS gene cluster. The distributions of genotype frequencies in the 422 subjects were in Hardy–Weinberg equilibrium (P > 0.05).

Table 4 Characteristics of the SNPs

As shown in Fig. 1, in the n-3 PUFAs major pattern, the concentration of DGLA in breast milk was higher in major allele homozygotes (MM) than in minor allele carriers (Mm/mm) for the FADS1 rs174547 gene (P = 0.019), whereas the concentration of ALA (P = 0.006) in breast milk was lower in MM than in Mm/mm for the FADS2 rs174575 gene. In the n-6 PUFAs major pattern, the concentration of AA (P = 0.003), DTA (P = 0.019), and DHA (P = 0.032) in breast milk was higher in MM than in Mm/mm with the FADS1 rs174547 gene; the concentration of AA (P = 0.005) and DTA (P = 0.026) in breast milk was higher in MM than in Mm/mm with the FADS1 rs174553 gene; the concentration of LA (P = 0.040), GLA (P = 0.042), AA (P = 0.002), DTA (P = 0.009), and DHA (P = 0.021) in breast milk was higher in MM than in Mm/mm with the FADS2 rs3834458 gene; the concentration of GLA (P = 0.047), AA (P = 0.004), and DTA (P = 0.022) in breast milk was higher in MM than in Mm/mm with the FADS2 rs1535 gene; and the concentration of AA (P = 0.045) in breast milk was higher in MM than in Mm/mm with the FADS2 rs174602 gene. In the essential PUFAs pattern, the concentration of AA in breast milk for the FADS2 rs174602 (P = 0.040) gene was higher in MM than in Mm/mm, and DTA was higher in MM than in Mm/mm for the FADS2 rs174575 gene (P = 0.023), but the concentration of LA in breast milk was lower in MM than in Mm/mm for the FADS3 rs1000778 (P = 0.023) gene. In addition, within the same dietary pattern, the concentration of PUFAs in breast milk did not differ between MM and Mm/mm of FADS2 rs498793, FADS3 rs174450, and FADS3 rs7115739.

Fig. 1
figure 1

Effects of the same dietary PUFA pattern and different genotypes on breast milk PUFAs. The blue color indicates that the content of this type of PUFA in breast milk was higher in MM than in Mm/mm (MM > Mm/mm). Red indicates that the content of this type of fatty acid in breast milk was lower in MM than in Mm/mm (MM < Mm/mm). NS indicates that no significant differences were present in the three dietary patterns in breast milk PUFAs between MM and Mm/mm under the same dietary PUFA pattern (P > 0.05). Triangles represent the n-3 PUFA major pattern, circles represent the n-6 PUFA major pattern, and squares represent the essential PUFA pattern. In the figure, only the symbols of the models with statistical differences (P < 0.05) are shown; the symbols of the models without statistical differences (P > 0.05) are not shown

Overall, as shown in Fig. 2, mothers carrying the minor alleles (Mm/mm) of the FADS1 rs174547, FADS1 rs174553, FADS2 rs3834458, and FADS2 rs1535 genes had significantly higher concentrations of LA, DGLA, AA, DTA, ALA, and DHA in their breast milk than mothers who were homozygous for the major allele (MM). Further analysis showed that the levels of PUFAs in the breast milk of mothers carrying the minor allele (Mm/mm) did not differ significantly across dietary patterns. In addition, regardless of the lactating mother’s adoption of any of the three dietary patterns, compared with Mm/mm, the milk of mothers homozygous for the major allele (MM) of the FADS2 rs174575 and FADS3 rs7115739 genes was significantly different for DGLA, AA, DTA, EPA, and DHA, which were significantly higher in the breast milk of their counterparts. Similarly, the concentrations of PUFAs in the breast milk of mothers homozygous for the major allele (MM) did not differ significantly across dietary patterns.

Fig. 2
figure 2

Effects of different dietary patterns of the same genotype on breast milk PUFAs. Blue indicates the major allele homozygotes, while red indicates minor allele carriers. NS indicates that no significant differences were present in the PUFAs in breast milk of lactating mothers with different dietary patterns under the same two genotypes. The star indicates that dietary model 1 was compared with the n-6 PUFAs major pattern, the diamond indicates that the n-3 PUFA major pattern was compared with the essential PUFAs pattern; the pentagon indicates that the n-6 PUFAs major pattern was compared with the essential PUFAs pattern; and the number in the symbol indicates the dietary model with higher breast milk PUFAs. In the figure, only the symbols of the models with statistical differences are shown; the symbols of the models without statistical differences are not shown

For mothers carrying the FADS2 rs174602 and FADS3 rs1000778 minor alleles (Mm/mm) and ingesting the essential PUFAs pattern, the concentration of LA in the breast milk was significantly higher than that in mothers carrying the same genotype and ingesting the other two dietary patterns. However, the concentrations of DTA, EPA, and DHA in breast milk with the essential PUFA pattern were the highest among the three patterns homozygous for the major allele (MM). Mothers who consumed the essential PUFAs pattern and were homozygous for the FADS2 rs498793 major allele (MM) had significantly higher concentrations of DGLA and DHA in their breast milk than mothers of the same genotype who chose the other two dietary patterns. Mothers who consumed the essential PUFA pattern and carried the FADS2 rs498793 minor allele (Mm/mm) had significantly higher concentrations of DTA in their breast milk than mothers of the same genotype who chose the other two dietary patterns. In addition, mothers who consumed the n-3 PUFAs dietary pattern and carried the FADS2 rs498793 allele had significantly lower EPA concentrations in their breast milk than mothers with the same genotype who chose the n-6 PUFAs dietary pattern. Among the Mm/mm of the three patterns, mothers who consumed the essential PUFA pattern and carried the FADS3 rs174450 minor allele (Mm/mm) had significantly higher concentrations of LA, AA, and DTA in their breast milk than those who consumed the n-6 PUFA major pattern with the same genotype; in contrast, mothers who selected the essential PUFA pattern carrying the MM had significantly higher concentrations of DHA in their breast milk than those who consumed the other two dietary patterns with the same genotype. No differences were observed in other PUFAs in the breast milk of mothers homozygous for both MM and Mm/mm under different dietary patterns. The details are shown in Fig. 2. (The specific values are described in detail in Supplementary Table 3– 12).



Source link