This Longevity-Boosting Diet May Disrupt The Depression-Dementia Link

The Mediterranean diet, which has been linked to an increased lifespan, better heart health, and even a decreased risk of developing type 2 diabetes, may also interrupt a link between depression and dementia, researchers say. 

A study, published in the Neurobiology of Ageing, looked at older participants (the average age was 75) and compared their depression levels to their dementia risk. 

The mental health condition is linked to an increased risk of developing dementia. 

But the scientists found that the usual pathways that seem to link depression to a higher risk of developing dementia appeared to be weakened by consumption of the Mediterranean diet. 

How might the Mediterranean diet help to break the depression-dementia link?

The scientists in this study placed the self-reported diets of participants from the Australian Imaging, Biomarker and Lifestyle study into three groups: the Mediterranean diet, the Western diet, and the Dietary Approaches to Stop Hypertension (DASH) diet. 

The DASH and Mediterranean diets focused heavily on whole foods, fruits, veggies, and legumes, and involved less meat, sugar, and saturated fats than the Western diet.

When clinicians test for early dementia in the blood, they look at biomarkers like patients’ amyloid-beta 42/40 ratio, phosphorylated tau (p-tau181, p-tau217), and neurofilament light chain (NfL).

The researchers wanted to see how those dementia-related biomarkers related to participants’ levels of anxiety and depression, and whether the diets they ate seemed to affect those biomarkers.

Among men with low or medium adherence to the Mediterranean diet, increased depression symptoms were linked to higher NfL biomarkers, indicating a possible increase in dementia risk. 

But among men with a high adherence to the Mediterranean diet (those who ate a Mediterranean diet tended to follow a lot of the rules of the DASH diet, too), this link disappeared. 

Does that mean the Mediterranean diet definitely cuts the dementia-depression link?

Not necessarily. This study only found an association between the diet, depression, and blood changes, meaning other factors could well be at play here. 

Still, the study authors write, “Our study presents evidence of the moderating effect of the MeDi [Mediterranean diet] on the relationship between depressive symptoms and specific Alzheimer’s disease-related blood-based biomarkers, particularly highlighting the influence of genetic predispositions and sex differences.

“Overall, a higher MeDi score potentially mitigates some of the negative impact depressive symptoms have on Alzheimer’s disease-related blood-based biomarker alterations,” they added. 

More research will be required to find a casual link between the two.