Recent studies from Edith Cowan University (ECU) indicate that our diet may play a significant role in the risk of developing both depression and Alzheimer’s disease (AD). There’s evidence that shows symptoms of depression can not only be a contributing factor to AD but may also arise as a result of early memory issues.
According to ECU researcher Dr. Samantha Gardener, following a healthy diet could potentially lessen some negative effects that depressive symptoms have on blood biomarkers associated with AD. These biomarkers are biological molecules present in the blood that can be observed and used to monitor the disease’s progression.
The study contributes valuable insights into how diet, depressive symptoms, and AD-related blood markers are interconnected.
“Dietary factors can influence brain health by affecting inflammation, oxidative stress, blood vessel function, neuroplasticity, and through the gut-brain connection. These biological mechanisms may have an impact on neurotransmitter systems and brain function, which would ultimately influence mood and cognitive abilities,” she explained.
The Mediterranean diet, known for its rich array of plant-based foods, olive oil, whole grains, and moderate red wine consumption, has been linked to lower rates of stroke, depression, cognitive decline, and AD. In contrast, a typical Western diet that contains higher levels of processed foods and sugars may lead to a quicker decline in specific brain functions.
“The Mediterranean diet is abundant in antioxidants, flavonoids, and other beneficial substances that help reduce inflammation and oxidative stress in the brain, along with healthy fats essential for learning and memory,” Dr. Gardener added.
“It’s important to recognize that while observational studies offer meaningful insights, randomized controlled trials examining the effects of specific dietary changes on depression and dementia related to AD are necessary. These trials could provide conclusive evidence about the advantages of specific dietary adjustments in managing these conditions.”
Alzheimer’s disease currently affects approximately 50 million people globally, with numbers projected to rise to 152 million by the year 2050.
The annual financial burden of the disease and other dementia-related illnesses is estimated to be around $909 billion, which represents about 1% of the world’s total GDP.
In Australia specifically, an estimated $3.7 billion is spent each year on diagnosing, treating, and caring for those with dementia.
ECU PhD student Hilal Salim Said Suliman Al Shamsi pointed out that depression is present in about 50% of individuals diagnosed with AD.
“A longitudinal study revealed that 40% of older adults diagnosed with depression transitioned to AD within a relatively short median follow-up time of 27 months. The same study found that the likelihood of progressing to AD was significantly greater for patients with a more recent history of depression within the last two years compared to those with a longer history,” he noted.
Currently, there are no definitive cures for AD, but Dr. Gardener mentioned that delaying its onset could lower the prevalence of the disease and its public health impact.
“Research has identified 14 modifiable risk factors that are estimated to account for around 45% of dementia cases globally. Among these 14 factors, five can be positively influenced through a healthy diet, including conditions like hypertension, obesity, alcohol consumption, and depression.
“There are also other modifiable factors such as regular physical activity and adequate sleep. If we address all these issues, we could theoretically prevent nearly 45% of dementia cases.”
