4. Discussion
atopy, breast milk consumed, consumption of seafood [No, breast milk
ATOPY
To the best of our knowledge, this is the first study to explore the association between maternal diet and serum LCPUFA levels in infants who have not yet started solid foods. The results indicated that the infants of lactating mothers who frequently consumed “Blue-back fish” and/or “White fish” from the list of 38 food items had higher levels of serum DHA than infants whose mothers did not consume these fish regularly. The study also found that infants who were predominantly breastfed had higher levels of serum DHA compared to those who were formula-fed. Even following multivariate analysis, frequent intake of “Blue-White fish” by lactating mothers and “feeding patterns” remained significant factors related to infant DHA levels, indicating that both factors were independently associated with higher serum DHA levels in infants. These results suggest that higher serum DHA levels might be more effectively achieved by frequent maternal consumption of “Blue-back fish” and/or “White fish”, or by prioritizing breastfeeding rather than relying on CMF supplemented with DHA.A previous meta-analysis revealed that the concentration of DHA in breast milk varies considerably by country and is generally higher in coastal populations with a higher consumption of seafood [No interaction of sex was evident in the association between maternal “Blue-White fish” intake frequency and infant serum DHA levels in this study. As demonstrated in a systematic review predominantly involving adults, females have higher plasma DHA levels (%) compared to males. This could be attributed to differences in n-3 LCPUFA synthesis from ALA, dietary patterns, and age [The present study also revealed that serum DHA levels were higher in breastfed infants compared to those fed CMF, even when it was supplemented with DHA. Contrary to our findings, most studies from Western countries indicated similar [In addition to DHA, AA is also crucial for infant growth, brain development, and overall health [Infants predominantly fed CMF had significantly higher levels of LA in their serum than breastfed infants. Moreover, the levels of ALA did not appear to be affected by feeding patterns. The CMF used in this study was supplemented with a higher percentage of LA (15.9%) than ALA (1.6%), both of which are found in high percentages in Japanese breast milk [One of the strengths of this study is that it used blood samples collected from 268 infants to measure 24 different types of fatty acids, despite the challenge of performing venous blood sampling in infants aged 5 to 6 months. This unique approach sets this study apart from most other studies on LCPUFA, which have relied on measuring their concentrations in breast milk.The results of this study should be considered in light of several limitations. First, due to a lack of information on the amount of breast milk intake, evaluation of the ratio of CMF to breast milk could not be accurately assessed despite the study being prospective. Infants exclusively fed with CMF were grouped together with those fed a mixture of breast milk and CMF in the CMF >100 mL/day category. Second, the exposure to CMF might not have been adequately classified, as the exact amount of CMF and the frequency of intake were not recorded, and data on the feeding patterns for 15% (31/207) of the participants had to be substituted with their feeding patterns at 3 months of age. Further, the amount of breast milk consumed could not usually be measured. Third, there might have been residual confounding as CMF doses were not randomized. For example, mothers who exclusively breastfeed their infants might be more likely to have a healthy lifestyle, exercise habits, and high socioeconomic status. Fourth, the questionnaire survey on food intake only considered the frequency of the consumption of specific foods and did not record the amount or cooking method, both of which would affect the results. Moreover, the questionnaires utilized in this study have not undergone validation and reliability assessments for evaluating dietary intake. Fifth, the results of the interview and questionnaire survey on food patterns might have been affected by a recall bias. Sixth, the levels of DHA in infant serum might be different from those in plasma, red blood cells, or in the brain. Seventh, the study population consisted of infants at risk of atopy, and hence, generalization of our findings to healthy infants might not be appropriate. Eighth, the sample size was calculated for the ABC trial and might not be adequate for the objectives of this cross-sectional study. Therefore, associations with food items other than “Blue-White fish” might have remained undetected. Lastly, the study was conducted in the center of Tokyo, and hence, the results might not be generalizable to populations in rural areas of Japan or to the populations of other countries.