Maintaining brain health is becoming a central concern with the increase in life expectancy and the expected sharp rise in the number of people living with dementia in the coming decades. In recent years, research has increasingly focused on lifestyle factors, and especially nutrition, as a significant component in protecting the brain. A large-scale study published in the journal JAMA Neurology now provides further evidence for this connection.
The researchers sought to examine whether eating patterns in midlife can affect cognitive health later in life. The findings indicate a significant link between adherence to a healthy diet and a lower risk of cognitive decline.
The study was based on data from three large and long-term cohort studies in the United States, which together included more than 159 thousand men and women. Participants completed detailed questionnaires over the years about their dietary habits, which allowed the researchers to track eating patterns over an extended period.
The diets examined were ranked according to adherence to six healthy eating patterns, including the DASH diet, which was originally designed to reduce blood pressure, the Alternative Healthy Eating Index AHEI, and a plant-based diet.
Cognitive health was assessed in two ways. The first was self-reporting of subjective decline in memory and thinking abilities, which is considered an early sign of future problems. In addition, a subgroup of participants underwent objective telephone-based cognitive tests that examined memory, verbal fluency, and other functions.
Nutrition has a major impact on cognitive decline
Across all six healthy eating patterns, a link was found between higher adherence to the diet and a lower risk of subjective cognitive decline. The DASH diet stood out in particular. Participants who reported the highest adherence to this diet had a 41 percent lower risk of significant cognitive decline compared to those who reported low adherence.
Other eating patterns also showed a protective effect, and the relationship was dose-dependent. The more participants adhered to a healthy diet, the more the risk decreased.
In the objective cognitive tests, a similar trend was found. Higher scores in healthy dietary patterns were associated with better performance in memory and verbal fluency. Among those who adhered to the DASH diet, cognitive performance was equivalent to that of a person almost one year younger.
Foods linked to better outcomes: Vegetables, fish, and wine
The researchers identified certain dietary components that were associated with better outcomes. Vegetables, fish, moderate wine consumption, and even salad dressing were found to be associated with a lower risk of cognitive decline. In contrast, red and processed meat, fried potatoes, and sugar-rich beverages were associated with poorer cognitive function.
The DASH diet emphasizes vegetables, fruits, whole grains, and lean proteins, alongside reducing sodium and sugar. It also encourages the intake of minerals such as calcium, potassium, and magnesium, which contribute to vascular health.
The window of opportunity for maintaining a diet: Ages 45-54
One of the important insights from the study is the importance of midlife. The researchers found that adherence to a healthy diet at ages 45 to 54 was particularly associated with better cognitive health later in life. This suggests that this period may constitute a critical window of opportunity for investing in future brain health.
This is an observational study, and therefore it indicates a correlation rather than causation. The dietary information was based on self-reporting, which may be influenced by memory or bias. However, the fact that the data were collected repeatedly over the years strengthens their reliability.
In addition, most participants were health professionals, white, and relatively educated, and therefore the findings may not represent the entire population.
Despite the limitations, this is one of the largest and most comprehensive studies in the field. The consistent conclusion across the different eating patterns is clear: A diet rich in plant-based foods and fish and low in processed food and sugar may contribute to maintaining brain function over time.
The practical message is simple. A daily choice of a plate rich in vegetables, fruits, whole grains, and high-quality protein may affect not only blood pressure and weight, but also memory and thinking in the years to come.