Estudio nutrigenómico del potencial impacto de la dieta sobre la composición de la leche materna y desarrollo del neonato

Resumen

Prevention of the current pandemic of obesity is one of the scientific challenges of our time. Energy imbalance as a consequence of caloric intakes above needs and/or insufficient energy expenditure is one of the best established causes of obesity. However, inter-generational transmission of maternal obesity through the reproductive process and metabolic programming in early stages are relevant factos that require further study and characterization to endorse new preventive strategies. Breastfeeding is a critical stage in the development of the newborn because milk can transfer information from mother to child via its composition in nutrients and other bioactive molecules, thus programming the adaptation to the environment. In addition, the composition of breast milk is modulated by maternal diet during lactation and probably also by the nutritional status preformed throughout her life. This thesis analyses the potential effect of maternal diet on the composition of human milk and infant development up to two years of age. For this, we recruited a cohort of 59 mother-infant pairs living in Mallorca between 2011 and 2014 in an observational study design. The study population was characterized by considering maternal anthropometric variables and infant growth up to two years of age. Maternal nutritional status was evaluated during the first three months of lactation; for each of these, triglyceride composition, total non-esterified fatty acids, the profile of individual fatty acid, total protein, leptin, adiponectin, lactoferrin, lysozyme, immunoglobulin A, free amino acids, the minerals calcium, magnesium, sodium, potassium, phosphorus and sulfur, the precursor of nicotinamide adenine dinucleotide and a battery of microRNAs selected based on their potential targets and their presence in milk was determined. Results show that overweight and maternal obesity during lactation (BMI!25kg/m2 ) affects the evolution of infant weight and growth was also modulated by sex, season of birth, gestational age and being or not being primiparous. Regarding the characteristics of the diet, the studied population presented a nutritional status similar to that of Spanish women in the same age range. However, a risk of deficiency was observed for vitamins B9, D and E and minerals calcium, zinc and iodine, as well as an excessive intake of vitamin B3 and sodium when recommendations were adapted to the physiological stage of lactation. We have also detected high intakes (twice or more of the respective recommendations) for vitamin B12, vitamin K, iron and phosphorus but low (inadequate by default) for vitamins A, B5 and B8 in a large proportion of the population studied. Supplementation with multinutrient complexes was observed in a significant part of the studied population and it did not appear to respond to their needs according to nutritional criteria. The composition of mature breast milk was associated with body mass index, diet and maternal age, weight gain during pregnancy, type of delivery, being or not being primiparous, the season in which the birth took place, gestational age, birth weight, stage of lactation, type of feeding, sex of the infant and growth rate. Integrated analysis of the differences and correlations found was performed. This, together with the use of statistical models, has allowed for a set of dietary (isoleucine, starch, phytosterols and vitamin D) and breast milk components (sodium, calcium, leptin, oleic acid, glutamate, threonine, miR-27a and miR-27b) to be defined as bioactive molecules with potential roles in early programming of obesity during lactation.