A longitudinal study of fatty acid profiles, macronutrient levels, and plasmin activity in human milk

IntroductionHuman milk provides nutrients essential for infant growth and health, levels of which are dynamic during lactation. MethodsIn this study, changes in macronutrients, fatty acids, and plasmin activities over the first six months of lactation in term milk were studied. ResultsThere was a significant influence of lactation stage on levels of protein and plasmin activities, but not on levels of fat and carbohydrate in term milk. Concerning fatty acids in term milk, levels of caproic acid and alpha-linolenic acid increased significantly (p < 0.05), whereas those of arachidonic acid and docosahexaenoic acid decreased, in the six months after birth. Significant impacts of maternal pre-pregnancy BMI and infant gender on fatty acid profiles were also found. Multivariate statistical analysis showed that protein level, plasmin activity, and several fatty acids (alpha-linolenic acid, lignoceric acid, and docasadienoic acid) contributed strongly to discrimination of milk from different lactational stages. DiscussionThe study demonstrates that not all but some fatty acids were influenced by lactation, whereas protein and protease levels showed clear decreasing trends during lactation, which may help in understanding the nutritional requirements of infants.

Automated summary

This study investigated the changes in macronutrients, fatty acids, and plasmin activities in term milk over the first six months of lactation. The results showed that protein and plasmin activities were significantly influenced by lactation stage, while levels of fat and carbohydrate were not. Among fatty acids, caproic acid and alpha-linolenic acid increased significantly, while arachidonic acid and docosahexaenoic acid decreased during the six months after birth. Maternal pre-pregnancy BMI and infant gender also had significant impacts on fatty acid profiles.