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Men who consumed more sodium showed faster episodic memory loss over six years—and the link held even after accounting for blood pressure.

Reviewed by Dietitian Emily Lachtrupp, M.S., RD

Key Points

• A study tracked more than 1,200 older adults to see how sodium affects memory over time.
• Men who consumed more sodium at the start of the study showed faster decline in episodic memory.
• No association was found in women, who consumed less sodium on average than men.

When you think about the health consequences of a high-salt diet, high blood pressure is probably the first thing that comes to mind. And that’s well-established science—cutting back on sodium can help reduce the risk of heart attack and stroke. But a growing body of research points to another reason to watch your salt intake: your brain.

Laboratory studies in rodents have consistently shown that high-salt diets can trigger inflammation, damage small blood vessels in the brain and impair memory. The trouble is that the evidence in humans has been considerably murkier, with some studies linking high-salt diets to cognitive decline and others finding no clear connection.

Researchers have started to suspect that one reason the results conflict is that sodium may not affect every person’s brain the same way. Men and women differ in how much sodium they typically consume and in their risk for cognitive decline, so looking at mixed-sex groups could mask real patterns.

A new study in Neurobiology of Aging set out to take a closer look, drawing on data from the long-running Australian Imaging, Biomarkers and Lifestyle (AIBL) study to track how sodium intake influenced memory in older adults over the course of six years. The findings suggest that when it comes to salt and the aging brain, sex matters. Let’s break down what they found.

How Was This Study Conducted?

Researchers followed 1,208 Australian adults with an average age of 71, all of whom had no signs of cognitive impairment at the start of the study. Participants filled out a food frequency questionnaire describing what they usually ate over the past year, and the researchers used that information to estimate each person’s average daily sodium intake.

Over the next six years, participants returned every 18 months for a full battery of cognitive tests measuring six categories: episodic recall (remembering specific events), recognition, executive function, language, attention and an overall preclinical Alzheimer’s cognitive score. The research team then looked for links between sodium intake and changes in each cognitive domain over time, adjusting for age, education and a gene variant known to raise Alzheimer’s risk. Because men and women tend to consume different amounts of sodium, the researchers also ran the analyses separately by sex.

What Did the Study Find?

When researchers looked at the group as a whole, they didn’t find a clear link between sodium intake and changes in memory or other cognitive skills. But once the results were broken down by sex, a pattern emerged: Men who reported eating more sodium at the start of the study showed significantly faster decline in episodic memory over the next six years compared with men who ate less.

On average, men in the study consumed about 2,350 milligrams of sodium per day while women averaged around 1,810 milligrams. The link to memory only showed up for episodic recall—the other cognitive domains didn’t show a significant association. And in women, there was no meaningful link between sodium and memory decline.

One especially interesting wrinkle: When researchers re-ran the analysis accounting for participants’ blood pressure, the association between sodium and memory decline didn’t change. That suggests high sodium may affect the brain through pathways that go beyond blood pressure—possibly by increasing inflammation, disrupting the blood-brain barrier or interfering with the small blood vessels that supply memory- regions like the hippocampus.

The study has important limitations. Sodium intake was self-reported and measured only once, at the start, so the numbers may be rough estimates and can’t capture changes people may have made to their diet over time. The cohort was also largely of European descent and relatively healthy at baseline, so the findings may not generalize to everyone. And because this is an observational study, it can show a connection between sodium and memory loss but can’t prove one caused the other.

How Does This Apply to Real Life?

Even with its caveats, this study adds to the evidence that what you eat affects how your brain ages. The average American adult consumes about 3,400 milligrams of sodium per day, well above the 2,300 mg daily limit recommended by federal dietary guidelines and far more than the 1,500 mg the American Heart Association suggests for optimal heart health. The vast majority of that sodium doesn’t come from the salt shaker—it comes from packaged and restaurant foods.

A few practical ways to cut back without making your meals taste flat:

• Cook more meals at home. Restaurant, takeout and prepared convenience meals are typically some of the biggest sodium sources in the American diet. Even simple home-cooked meals usually contain less sodium than their restaurant equivalents.
• Read labels on the foods you buy most often. Breads, deli meats, canned soups, sauces, frozen meals and salty snacks are among the top sources of sodium in the U.S. Comparing two brands of the same product can sometimes save you hundreds of milligrams per serving.
• Reach for herbs, citrus and spices before salt. Garlic, lemon juice, fresh herbs, smoked paprika, black pepper and chili flakes can add a lot of flavor without much sodium.
• Fill your plate with whole foods. Fresh fruits, vegetables, beans, nuts and unprocessed meats are naturally low in sodium and, and some of those foods are associated with better cognitive health.

If you’re a man over 60 (or often cooking for one), these tweaks might be worth extra attention given the current findings.

Our Expert Take

A new six-year study in Neurobiology of Aging suggests that older men who eat more sodium experience faster decline in episodic memory than men who eat less—and blood pressure alone doesn’t seem to explain the link. No similar association was found in women, who consumed less sodium on average. The research adds to a growing body of evidence suggesting dietary sodium may affect brain health through pathways beyond its well-known effect on blood pressure.

While a single observational study can’t tell you exactly how much salt is too much for your brain, cutting back on processed and restaurant foods—the biggest sources of sodium in most diets—is an easy, evidence-backed habit that supports your heart and, very possibly, your mind over the long term.