New Study Warns That Too Little Salt May Impair Memory Just as Much as Excess Sodium
When it comes to preparing meals, getting the seasoning right is a constant balancing act. While medical professionals have long warned the public about the dangers of consuming too much sodium, a recent study suggests that going too far in the opposite direction may be just as harmful. Researchers investigating the gut-brain connection have discovered that both severely restricted salt intake and excessive salt consumption can impair cognitive function, specifically damaging short-term working memory and long-term recognition memory.
The findings, which were recently published in the journal Food Research International, shed light on how dietary salt extremes impact neurological health. To make their research as relevant to human biology as possible, the scientific team utilized a humanized mouse model. Instead of relying on standard laboratory mice, the researchers cleared out the animals’ natural gut bacteria using antibiotics and then introduced transplanted gut microbiomes derived from healthy human donors.
Once their guts were humanized, the mice were randomly assigned to one of three specific custom diets for a duration of 14 weeks. A control group consumed a standard 0.5% salt diet, a low-salt group received a 0.1% salt diet to simulate severe sodium restriction, and a high-salt group was given an 8.0% salt diet to model extreme sodium consumption. Afterward, the team evaluated the rodents using a series of behavioral assessments, including the Y-maze test for spatial memory, a novel object recognition test, and an open-field arena test to monitor movement and anxiety-like behaviors.
The evaluation revealed that mice on both the low-salt and high-salt diets performed worse on memory tasks than the control group. However, the underlying biological mechanisms causing these cognitive deficits differed significantly depending on whether the diet lacked salt or featured an excess of it.
Different Pathways, Similar Cognitive Deficits
According to the researchers, inadequate sodium intake impaired memory through changes centered inside the hippocampus, which serves as the brain’s primary memory center. Specifically, a low-salt diet led to a drop in critical synaptic proteins—such as SYN1, PSD95, and BDNF—and suppressed CREB activation. Because neurons rely on these essential tools to build memories and adapt to new information, weakening them diminished the brain’s capacity to form memories effectively.
Conversely, a high-salt diet disrupted cognitive function through inflammatory pathways. Excessive sodium significantly increased circulating pro-inflammatory signals in the blood and altered the gut microbiota. This shift lowered fecal levels of beneficial metabolites like propionate and butyrate, while simultaneously triggering oxidative stress markers in the intestine. These physical changes frequently correlate with heightened anxiety-like behavior.
The Broader Context of Sodium Intake
Public health guidelines worldwide consistently emphasize reducing dietary sodium to protect cardiovascular health and lower the risk of high blood pressure. Modern diets, particularly those heavy in ultraprocessed foods and fast food, frequently exceed recommended daily limits. Despite the well-documented hazards of high sodium intake, scientists note that relatively little was previously known about how severe, long-term salt restriction influences neurological health and brain function.
The authors of the study emphasize the importance of maintaining a balanced, normal sodium intake for preserving both gut and overall brain health. While a diet lacking in salt can starve the brain of vital chemical signals originating in the gut, an excess of salt inflicts inflammatory damage on the body. Future investigations aim to determine the lowest safe threshold for dietary salt intake and explore whether restoring specific gut microbe metabolites could help reverse memory and thinking problems associated with salt imbalances.
Source: Medical Xpress
