New research from Edith Cowan University (ECU) suggests that what we eat could play a role in reducing the risk of both depression and Alzheimer’s disease.
Depression and Alzheimer’s are often connected—depression can be an early warning sign of Alzheimer’s, and those with memory problems often experience depression as a reaction. Understanding this link could help in finding ways to lower the risk of developing Alzheimer’s later in life.
The study, published in the journal Neurobiology of Aging, focused on how diet affects biological markers in the blood that are linked to Alzheimer’s. These markers provide clues about the progression of the disease.
According to ECU researcher Dr. Samantha Gardener, a healthy diet may help counter some of the negative effects depression has on these Alzheimer’s-related blood markers.
One of the main reasons diet is important for brain health is because it affects inflammation, blood circulation, brain cell function, and even gut health. These factors can impact mood, memory, and overall brain function. Scientists believe that certain diets may help protect the brain, while others could speed up cognitive decline.
A good example is the Mediterranean diet, which is rich in plant-based foods, olive oil, whole grains, nuts, and moderate amounts of red wine. Studies have linked this diet to a lower risk of stroke, depression, and Alzheimer’s disease.
In contrast, a typical Western diet, which includes a lot of processed foods, sugary drinks, and unhealthy fats, has been associated with a decline in brain function.
Dr. Gardener explains that the Mediterranean diet contains antioxidants and other nutrients that help reduce inflammation and stress in the brain. It also includes healthy fats that are essential for memory and learning. These benefits may help protect against Alzheimer’s disease and other forms of dementia.
However, she also pointed out that while these findings are promising, more studies are needed—especially clinical trials that directly test how specific diets influence depression and dementia risk.
Alzheimer’s is a growing global problem. Currently, about 50 million people worldwide are living with the disease, and that number is expected to triple to 152 million by 2050.
The economic impact is enormous, with annual costs estimated at $909 billion, or about 1% of the global economy. In Australia alone, around $3.7 billion is spent each year on diagnosing, treating, and caring for people with dementia.
ECU Ph.D. student Hilal Salim Said Suliman Al Shamsi highlighted the strong connection between depression and Alzheimer’s. Among people diagnosed with Alzheimer’s, about 50% also experience depression.
A study following older adults with depression found that 40% later developed Alzheimer’s within just 27 months. The risk was even higher for those who had experienced depression in the previous two years.
At the moment, there is no cure for Alzheimer’s, but Dr. Gardener believes that delaying its onset could reduce its impact. Research suggests that around 45% of dementia cases could be prevented by changing certain lifestyle habits.
There are 14 risk factors linked to dementia, and five of them—high blood pressure, obesity, alcohol consumption, depression, and poor diet—can be improved through healthier eating. Other lifestyle changes, such as regular exercise and getting enough sleep, also play a role.
This study adds to growing evidence that a healthy diet can help protect brain function and lower the risk of serious conditions like Alzheimer’s. While more research is needed, the findings suggest that simple changes in what we eat could have long-term benefits for mental and cognitive health.
Review and Analysis
This study highlights an important connection between diet, mental health, and brain function. The growing rates of Alzheimer’s and dementia worldwide make it crucial to explore ways to reduce risk, especially since there is no cure.
One of the most valuable takeaways is that Alzheimer’s does not happen overnight—it develops gradually, often starting with early warning signs like depression. The study strengthens the case that improving diet could be one way to slow down or even prevent cognitive decline.
The Mediterranean diet, in particular, has been widely studied for its health benefits, and this research provides further support for its role in protecting brain health. In contrast, the Western diet’s negative effects reinforce concerns about processed foods and high sugar intake.
Another key point is that small lifestyle changes can add up. If nearly half of all dementia cases could be prevented by addressing diet, exercise, and other factors, then public health efforts should focus on making these changes more accessible and widely understood.
While this research is promising, it is still based on observational data. More controlled studies are needed to confirm whether specific diets can directly lower the risk of Alzheimer’s and depression. That said, given the well-documented health benefits of nutritious diets, adopting healthier eating habits seems like a wise choice for overall well-being.
This study reinforces the importance of long-term health habits. By making better food choices today, we may be able to protect our brains and improve our quality of life in the future.
If you care about brain health, please read studies about vitamin D deficiency linked to Alzheimer’s and vascular dementia, and blood pressure problem at night may increase Alzheimer’s risk.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and epilepsy drug may help treat Alzheimer’s disease.
The research findings can be found in Neurobiology of Aging.
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