Poor nutrition a risk factor for cognitive decline & dementia, says KCL team
The study, conducted by researchers at King’s College London, identifies the importance of vitamin D levels, carotenoid and lipid levels in slowing the rate of cell death, particularly in the brain.
“While more work is undoubtedly needed to fully understand how diet and exercise might modulate hippocampal neurogenesis, our findings may represent an effective early preventative strategy against CD and dementia,” says Dr Andrea du Preez, the study’s first author from King’s Institute of Psychiatry, Psychology & Neuroscience (IoPPN).
The experiment involved taking the blood samples of 418 adults over the age of 65 collected 12-years prior to CD and dementia diagnosis and tested on human hippocampal stems cells.
Data on each subject’s lifestyle were collected, and cognition and dementia status were measured every two to three years over a 12-year period.
Results established that 12 years before diagnosis, both CD and Alzheimer’s were linked with levels of neural stem cell death.
The team, which included colleagues from the University of Bordeaux, specifically found nutrition levels of vitamin D, carotenoids and lipids linked with how fast the cells died.
Specifically, researchers found that reduced physical activity and increased malnutrition both increased cell death which in turn increased the risk for future CD.
Potential CD warnings
“Our study has demonstrated not only that there are individual markers of hippocampal neurogenesis associated with CD and dementia 12 years later, but also that there is some degree of specificity with respect to diagnoses of dementia subtypes,” explains Dr Sandrine Thuret, the study's lead investigator.
“If an individual displays an increase in their levels of cell death during differentiation (when neural stem cells are becoming neurons), we can look at this as a potential warning sign of CD,” adds Dr Thuret, who is also Reader in Neuroscience & Mental Health at the IoPPN.
“Conversely, a decrease in levels of cell death during proliferation (the process by which a single cell divides into a pair) and reduced hippocampal progenitor cell integrity could be viewed as a predictor for Alzheimer’s Disease and Vascular dementia, respectively.”
Whilst understanding of cognitive ageing mechanisms has improved, effective strategies to prevent its onset have remained limited.
Several lifestyle factors have emerged as potentially modifiable risk factors for CD and dementia, two of which includes diet and exercise.
Along with evidence of the Mediterranean diet’s role in slowing down CD and reduced dementia risk, there is also evidence of a protective effect for folate and flavonoids in dark leafy vegetables, omega-3 fatty acids, and vitamin D in seafood, as well as caffeine.
The recent identification of a signature of metabolites predictive of CD also holds much promise as does the protective role of coffee, cocoa, fish, and red wine.
Discussing the findings, the team centred on the SRY-Box Transcription Factor 2 (SOX2) levels, a marker of hippocampal cell health and a regulator of the fate of stems cells.
The team commented that single dietary nutrients may be more relevant to %SOX2, highlighting a positive link between %SOX2 and ß-cryptoxanthin—a biomarker for fruit and vegetable intake.
“This is particularly interesting, given that both have been associated with cancers, and cardiovascular and neurodegenerative disease, with increased levels of ß-cryptoxanthin known to have a protective effect against these conditions,” the team points out.
“Furthermore, reduced carotenoid levels have been associated with dementia, suggesting that this particular dietary measure could play a key role in modulating SOX2 levels that subsequently promote or aggravate disease pathology.”
The researchers acknowledged though that in a similar vein to Alzheimer's disease (AD), they could only demonstrate associations between these factors and did not find a mediatory effect of %SOX2.
Source: Alzheimer's & Dementia: The Journal of the Alzheimer's Association
Published online: doi.org/10.1002/alz.12428
“The serum metabolome mediates the concert of diet, exercise, and neurogenesis, determining the risk for cognitive decline and dementia.”
Authors: Andrea Du Preez et al.