Mediterranean-style diet benefits maternal and infant health

Two new studies from the University of Barcelona (UB) have found that a Mediterranean-style diet, rich in fibre, vegetable proteins and healthy fats, benefits maternal health during pregnancy and breastfeeding. These studies, both published in the journal eBioMedicine, provide new insights that may lead to more precise dietary guidelines for pregnant and breastfeeding women.

Establishing optimal nutritional habits during pregnancy, lactation and early life is crucial for the health and wellbeing of mother and baby. However, the associated mechanisms linking maternal diet to maternal and infant health outcomes are still poorly understood.

The first study, at the preclinical level, compared the effects of two different diets during gestation and lactation on microbiota composition, immunity and lipid metabolism: the Mediterranean-like D1 diet, rich in fibre and vegetable protein, and a Western D2 diet, richer in animal protein and fats. During the nutritional intervention, various biological samples were analysed to see the effects of each diet on the epithelial barrier, lipid metabolism, microbiota composition, metabolites and immunity.

“The results reveal that a diet similar to the Mediterranean diet and enriched with fish oil, soya protein and inulin has beneficial effects on lipid metabolism, the composition of the microbiota and the immune response during pregnancy and breastfeeding, and improves maternal health,” said UB’s Professor Francisco J Pérez-Cano, joint leader on both studies.

“Furthermore, if this diet is maintained during breastfeeding, it seems to more effectively reverse the physiological changes that occur during pregnancy, supporting immune function and limiting fat accumulation.”

The second study showed that a maternal diet rich in plant protein, fibre and polyunsaturated fatty acids reduces the severity and frequency of infections in infants through the modulating effect of gut microbiota on the immune system. The study, conducted on infants and animal models, reinforces the importance of maternal nutrition during pregnancy and lactation to strengthen infant health.

In this context, the influence of the maternal diet emerges as a key factor in the composition of the defensive elements of milk during lactation. As essential elements, immunoglobulin A (IgA) in human milk and the diversity of the microbiota demonstrate their protective role against infections in infants.

“The study may also help to better understand the relationship between maternal diet, bioactive components of breast milk, infant microbiota and infant immunity,” said Pérez-Cano and joint study leader M Carmen Collado, from Spain’s Institute of Agrochemistry and Food Technology. “In the future, further research will be necessary to obtain more solid conclusions and better understand the mechanisms involved.”

Meanwhile, a separate study out of Flinders University and The University of Adelaide has linked Australia’s rising incidence of gestational diabetes mellitus (GDM) in part to excess maternal folate levels, due to the dual impact of folic acid (FA, or synthetic folate) in food fortification and higher-than-recommended supplementation doses during pregnancy. Adequate folate intake is essential for DNA formation and proper cell growth and development, but this study — published in the journal Nutrients — showed that excess maternal folate significantly increased GDM risk in the post-fortification pregnancy cohort.

“The placenta is central to regulating maternal glucose tolerance in pregnancy, so we need to understand how high FA intake affects placental function and, in turn, insulin resistance and gestational diabetes risk,” noted study co-leader Dr Tanja Jankovic-Karasoulos, from Adelaide’s Robinson Research Institute.

The researchers emphasise the importance of adequate folate in pregnancy but highlight the need to establish a safe upper limit of FA intake. They would also like to see improved guidelines on FA supplementation during pregnancy, which would protect the fetus right at the beginning of gestation against neural tube defects but also protect the mother and fetus from high blood glucose.

“The use of FA is widely recommended worldwide, but we need to keep investigating unexpected implications, plus how to identify women at risk of gestational diabetes early in pregnancy to protect the baby from adverse effects of high maternal blood glucose for the best start in life,” said study co-leader Professor Claire Roberts, from the Flinders Health and Medical Research Institute.

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