Scientists in China have found that what you eat may influence brain health as you age.
Their study suggests that a diet high in sodium (a major component of salt) but low in potassium may increase the risk of memory problems — a common early sign of dementia.
Dementia is a condition that affects memory, thinking, and decision-making. In severe cases, it can interfere with daily life and independence.
It is becoming one of the leading causes of illness and death among older adults worldwide.
China has the largest aging population in the world, making dementia a growing public health concern. Because dementia cannot currently be reversed and effective treatments remain limited, prevention and early detection are critically important.
Previous research has shown that lifestyle factors such as exercise, diet, and sleep affect brain health. However, the specific role of dietary sodium and potassium — two minerals commonly found in everyday foods — has not been thoroughly studied.
The research team examined how dietary sodium, potassium, the sodium-to-potassium ratio, and salt intake were related to cognitive function in older adults in China.
The study included 4,213 participants aged 50 years and older. Researchers evaluated brain function using cognitive tests along with participants’ self-reported dietary information.
What the study found
The researchers found that high sodium intake (more than 5,593 mg per day) and a high sodium-to-potassium ratio (greater than 3.8) were associated with a higher risk of memory problems in older adults.
In contrast, higher potassium intake (more than 1,653 mg per day) was linked to better cognitive performance.
The team also estimated that replacing 1,000 mg of daily sodium with the same amount of potassium could improve cognitive test scores by about one point.
The researchers suggest that the effects of sodium and potassium on brain function may be partly related to cardiovascular health, since these minerals influence heart and blood vessel function. They also noted that salt intake may affect brain health through its impact on sleep.
Despite more than a decade of public health campaigns encouraging reduced salt intake, average sodium consumption in China remains high — exceeding World Health Organization recommendations.
At the same time, potassium intake remains too low. In this study, the average intake was about 1,499 mg per day, far below China’s recommended level of 3,600 mg.
These findings support earlier research suggesting that the balance between sodium and potassium in the diet may be more important for brain health than either nutrient alone.
Understanding how diet affects brain health could help identify practical ways to reduce dementia risk.
Other research suggests that dietary patterns such as the Mediterranean diet, as well as nutrients like vitamin B and vitamin D, may also support brain health and lower disease risk.
The study was conducted by Ai Zhao and colleagues and published in Global Transitions.
