Dietary sodium restrictions during pregnancy and lactation are widely practiced and often encouraged, yet the neurological consequences for offspring have remained largely uncharacterized. This research challenges the assumption that maternal sodium restriction is uniformly safe, revealing lasting effects on brain architecture and cognitive function that persist well into adulthood.
Using C57BL/6J mice, researchers compared offspring born to dams fed either a standard sodium diet (0.30% Na) or a low-sodium diet (0.04% Na) from birth through weaning at postnatal day 21. After weaning, all offspring transitioned to a standard diet. When tested at 60–80 days of age — equivalent to young adulthood — offspring from low-sodium dams displayed impaired spatial memory and learning alongside elevated anxiety-like behaviors. Critically, hippocampal neurogenesis was measurably reduced, and the transcription factor Sox2 — a master regulator of neural stem cell identity — showed altered expression along with disrupted downstream signaling and modified epigenetic regulation. These effects were sex-differentiated, with the magnitude varying between male and female offspring.
This finding sits at an important intersection of nutritional epigenetics and developmental neuroscience. Sox2 dysregulation is particularly significant: it governs the maintenance of neural progenitor pools in the dentate gyrus, a hippocampal subregion central to spatial memory and emotional regulation. Epigenetic alterations in this pathway are concerning precisely because they can be heritable and long-lasting, potentially persisting beyond the developmental window when intervention is possible. The study is animal-based, which limits direct human translation, and the 0.04% sodium diet is more extreme than typical low-sodium clinical recommendations. Nonetheless, the findings raise a legitimate research question about whether subclinical sodium deficits during lactation — a period when many mothers self-restrict — contribute to neurodevelopmental variability in human infants. This is incremental but mechanistically important work warranting follow-up in larger mammalian models.
