A Mediterranean Diet Might Protect You Against Memory Loss and Dementia

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A Mediterranean Diet Might Protect You Against Memory Loss and Dementia

Jim Windell

             Alzheimer's disease is caused by protein deposits in the brain and the rapid loss of brain matter. In fact, in Alzheimer's disease, neurons in the brain die. The cause – for the most part – of the death of neurons are certain protein deposits in the brains. These proteins, so-called beta-amyloid proteins, form clumps (plaques) between neurons, and tau proteins stick together the inside of neurons. What is not so clear is how these deposits come about. But besides the protein deposits in the brain, Alzheimer’s disease features a rapidly progressive atrophy; that is, a shrinking of the brain volume. The protein deposits and the shrinking of the brain volume lead to Alzheimer's symptoms, which include memory loss, disorientation, agitation and challenging behaviors.

           But a Mediterranean diet rich in fish, vegetables and olive oil might protect the brain from these disease triggers.

           Scientists at the DZNE, the German Center for Neurodegenerative Diseases, have now found in a study that a regular Mediterranean-like dietary pattern with relatively more intake of vegetables, legumes, fruit, cereals, fish and monounsaturated fatty acids, such as from olive oil, may protect against protein deposits in the brain and brain atrophy. This diet has a low intake of dairy products, red meat and saturated fatty acids.

           In a study led by Prof. Michael Wagner, head of a research group at the DZNE and senior psychologist at the memory clinic of the University Hospital Bonn, 512 subjects with an average age of around seventy years took part in the research. Of the 512 participants, 169 of them were cognitively healthy, while 343 were identified as having a higher risk of developing Alzheimer's disease. Those at risk were so identified because of subjective memory impairment, mild cognitive impairment that is the precursor to dementia, or first-degree relationship with patients diagnosed with Alzheimer's disease. The participants first filled out a questionnaire in which they indicated which portions of 148 different foods they had eaten in the past months. Those who frequently ate healthy foods typical of the Mediterranean diet, such as fish, vegetables and fruit, and only occasionally consumed foods such as red meat, scored highly on a scale.

           The researchers then investigated brain atrophy by performing brain scans with magnetic resonance imaging (MRI) scanners to determine brain volume. In addition, all subjects underwent various neuropsychological tests in which cognitive abilities such as memory functions were examined. The research team also looked at biomarker levels (measured values) for amyloid beta proteins and tau proteins in the cerebrospinal fluid (CSF) of 226 subjects.

           Michael Wagner and his research team found that those participants who ate an unhealthy diet had more pathological levels of these biomarkers in the cerebrospinal fluid than those who regularly ate a Mediterranean-like diet. In the memory tests, the participants who did not adhere to the Mediterranean diet also performed worse than those who regularly ate fish and vegetables.

           “There was also a significant positive correlation between a closer adherence to a Mediterranean-like diet and a higher volume of the hippocampus,” said Tommaso Ballarini, Ph.D., postdoctoral fellow in Michael Wagner's research group and lead author of the study. The hippocampus, Ballarini explained, is an area of the brain that is considered the control center of memory. “It shrinks early and severely in Alzheimer's disease," He added.  

           "It is possible that the Mediterranean diet protects the brain from protein deposits and brain atrophy that can cause memory loss and dementia,” Ballarini said. “But the biological mechanism underlying this will have to be clarified in future studies." As a next step, Ballarini and Wagner now plan to re-examine the same study participants in four to five years to explore how their nutrition – Mediterranean-like or unhealthy – affects brain aging over time.

           This nutrition study was funded by the Diet-Body-Brain competence cluster of the German Federal Ministry of Education and Research (BMBF) and took place as part of the so-called DELCODE study of the DZNE, which does nationwide research on the early phase of Alzheimer's disease.

           Previous studies of the Mediterranean diet have suggested that the diet may preserve cognitive functions, could reduce bone loss in people with osteoporosis, may preserve memory functions, and may improve the function of high-density lipoprotein, the so-called good cholesterol.

           To read the original article, find it with this reference:

Tommaso Ballarini, Debora Melo Van Lent, Julia Brunner, Alina Schröder, Steffen Wolfsgruber, Slawek Altenstein, Frederic Brosseron, Katharina Buerger, Peter Dechent, Laura Dobisch, Emrah Duzel, Birgit Ertl-Wagner, Klaus Fliessbach, Silka Dawn Freiesleben, Ingo Frommann, Wenzel Glanz, Dietmar Hauser, John Dylan Haynes, Michael T. Heneka, Daniel Janowitz, Ingo Kilimann, Christoph Laske, Franziska Maier, Coraline Danielle Metzger, Matthias Munk, Robert Perneczky, Oliver Peters, Josef Priller, Alfredo Ramirez, Boris Rauchmann, Nina Roy, Klaus Scheffler, Anja Schneider, Annika Spottke, Eike Jakob Spruth, Stefan J. Teipel, Ruth Vukovich, Jens Wiltfang, Frank Jessen, Michael Wagner & Delcode Study Group. (2021). Mediterranean Diet, Alzheimer Disease Biomarkers and Brain Atrophy in Old Age. Neurology. DOI: 10.1212/WNL.0000000000012067

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