Relationship Between Nutritional Consumption of Breastfeeding Mothers and Breast Milk Composition During Lactation

Breast milk is the best source of nutrition for infants because it contains essential nutrients and other bioactive factors (e.g., hormones, antibodies, bioactive molecules, stem cells) in the right balance. The macronutrient values in breast milk of mature term babies have been reported as protein 0.9-1.2 gr/dl, fat 3.2-3.6 gr/dl, lactose 6.7-7.8 gr/dl. . It is known that exclusive breastfeeding in the first six months of life and breastfeeding with complementary foods at two years of age and beyond is associated with a reduced incidence of infections and chronic diseases . Studies have shown that breastfeeding has short- and long-term benefits and protective effects. It is known that breast milk protects the baby from chronic diseases, especially Type 1 and Type 2 diabetes, obesity, hypertension, cardiovascular diseases, hyperlipidemia and some types of cancer , has positive effects on the cognitive development of the baby , and this effect continues for many years. These protective effects are controversial and may differ according to maternal phenotypes . Compared to infant formulas with standardized compositions, the composition of breast milk changes dynamically because it is produced by women with significantly different genotypes and phenotypes . The composition of breast milk is affected by many maternal, infant and physiological factors. Some of these factors vary according to whether the baby is term or preterm, whether the milk is colostrum secreted in the first 5 days after birth, transitional milk secreted between 5 days and 2 weeks, and mature milk produced after the 2nd week, the mother's nutritional status, body mass index, parity, gender of the baby, birth weight of the baby, duration of breastfeeding, and the method of milk delivery (expressing/breastfeeding), etc.. However, the effect of maternal nutrition on breast milk composition has not been well defined. There are some limitations in previous studies evaluating the relationship between maternal factors and breast milk composition. These include the lack of standard milk expression protocols, no specific time (time of day, foremilk or hindmilk) for expressing milk samples , and exclusive breastfeeding or the lack of information on the analysis of milk composition. In addition, most of the existing studies were conducted in the 1980s and 1990s and did not use separate up-to-date analyzers for protein, fat and lactose for milk composition analysis. Bzikowska-Jura et al., (2018) investigated the relationship between maternal nutrition and breast milk composition. However, in this study, mothers used a mix of hand and manual milking methods and the time elapsed since the baby's last feeding, which is another factor that may affect the content of breast milk, was not specified. Due to all these methodological differences, the effect of maternal diet on breast milk composition has not been clarified. These limitations may affect the actual assessment of these relationships. In this context, our study seeks answers to the effect of maternal diet on breast milk composition.