Geriatric Psychiatry Research Update: December 2018
Three news studies show how eating habits and other lifestyle factors affect cognition and brain imaging may be useful in predicting dementia.
Three news studies in geriatric psychiatry show how eating habits and other lifestyle factors affect cognition and brain imaging may be useful in predicting dementia: Coffee may protect against the development of Alzheimer disease and Parkinson disease; and MRI scans show promise in predicting dementia; and long-term consumption of fruits and vegetables may be associated with a lower risk of memory loss over time in men.
A group of compounds known as phenylindanes, which emerge as a result of the roasting process for coffee beans, appear to inhibit the clumping of both amyloid beta and tau, two protein fragments common in Alzheimer disease and Parkinson disease. Three instant coffee extracts (light roast, dark roast, and decaffeinated dark roast) and six coffee components, including phenylindane and caffeine, were investigated for their ability to inhibit the fibrillization of amyloid beta and tau proteins. All instant coffee extracts inhibited fibrillization of amyloid beta and tau. Dark roast coffee extracts, which contain higher quantities of phenylindane, were more potent inhibitors of amyloid beta than light roast coffee extract. Pure caffeine had no effect on amyloid beta or tau.
Clinical Implications: “It’s the first time anybody’s investigated how phenylindanes interact with the proteins that are responsible for Alzheimer’s and Parkinson’s,” said Ross Mancini, PhD, research fellow in medicinal chemistry at the Krembil Research Institute, University Health Network, Toronto, ON, Canada. “The next step would be to investigate how beneficial these compounds are, and whether they have the ability to enter the bloodstream, or cross the blood-brain barrier.”
Source: Mancini RS, Wang Y, Weaver DF. Phenylindanes in Brewed Coffee Inhibit Amyloid-Beta and Tau Aggregation Front. Neurosci. 2018;12:735.
A single MRI scan can predict dementia on average 2.6 years before memory loss is clinically detectable. Information from the Alzheimer’s Disease Neuroimaging Initiative was used to identify 10 people whose cognitive skills had declined over a two-year period and 10 age- and sex-matched controls whose cognitive skills had not declined. The average age of both groups was 73 years. Diffusion tensor MRI scans, which assess the health of the brain’s white matter, were taken just before the two-year period for all 20 participants.
Those who experienced cognitive decline had significantly more signs of white matter damage. A refined analysis of white matter integrity in a separate sample of 61 people was used to predict cognitive decline with 89% accuracy when looking at the whole brain. Focusing on specific parts of the brain most likely to show damage, the accuracy rose to 95%.
Clinical Implications: “We could tell that the individuals who went on to develop dementia have these differences on diffusion MRI, compared with scans of cognitively normal people whose memory and thinking skills remained intact,” said lead author Cyrus A. Raji, MD, PhD. “What we need now, before we can bring it into the clinic, is to get more control subjects and develop computerized tools that can more reliably compare individual patients’ scans to a baseline normal standard. With that, doctors might soon be able to tell people whether they are likely to have Alzheimer’s develop in the next few years.”
Source: Raji C, Wang MB, Moe E, et al. Tract Based Spatial Statistics in Persons who Will Develop Alzheimer’s Dementia: A Study from the Alzheimer’s Disease Neuroimaging Initiative. Presentation at Radiological Society of North America meeting in Chicago, November 25, 2018
Long-term intake of vegetables and fruits and drinking orange juice plays a beneficial role in reducing the risk of late-life subjective cognitive function. In a study of 27,842 men, average age 51 years, average dietary intake was calculated from 5 repeated food frequency questionnaires collected every 4 years until 2002. Subjective cognitive function was assessed twice (2008 and 2012) using a 6-item questionnaire; validity was supported by strong associations with APO ε4 genotype.
After controlling for major non-dietary factors and total energy intake, higher intakes of total vegetables, total fruits, and fruit juice were each significantly associated with lower odds of moderate or poor subjective cognitive function. Higher consumption of vegetables and fruits 18 to 22 years before subjective cognitive function assessment was associated with lower odds of poor subjective cognitive function.
Clinical Implications: “One of the most important factors in this study is that we were able to research and track such a large group of men over a 20-year period of time, allowing for very telling results,” said lead author Changzheng Yuan, ScD, of Harvard T.H. Chan School of Public Health in Boston, MA. “Our studies provide further evidence dietary choices can be important to maintain your brain health.”
Source: Yuan C, Fondell E, Bhushan A, et al. Long-term intake of vegetables and fruits and subjective cognitive function in US men. Neurology. 2018 Nov 21; Epub ahead of print.