News Release 6-May-2021
DZNE – German Center for Neurodegenerative Diseases
In Alzheimer’s disease, neurons in the brain die. Largely responsible for the death of neurons are certain protein deposits in the brains of affected individuals: So-called beta-amyloid proteins, which form clumps (plaques) between neurons, and tau proteins, which stick together the inside of neurons. The causes of these deposits are as yet unclear. In addition, a rapidly progressive atrophy, i.e. a shrinking of the brain volume, can be observed in affected persons. Alzheimer’s symptoms such as memory loss, disorientation, agitation and challenging behavior are the consequences.
Scientists at the DZNE 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, have now found in a study that a regular Mediterranean (diet)-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.
A nationwide study
A total of 512 subjects with an average age of around seventy years took part in the study. 169 of them were cognitively healthy, while 343 were identified as having a higher risk of developing Alzheimer’s disease – due to subjective memory impairment, mild cognitive impairment that is the precursor to dementia, or first-degree relationship with patients diagnosed with Alzheimer’s disease. The 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 – that period before pronounced symptoms appear.
“People in the second half of life have constant eating habits. We analyzed whether the study participants regularly eat a Mediterranean diet – and whether this might have an impact on brain health “, said Prof. Michael Wagner. 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.
An extensive test series
The scientists then investigated brain atrophy: they performed 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 so-called cerebrospinal fluid (CSF) of 226 subjects.
The researchers, led by Michael Wagner, found that those 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. The hippocampus is an area of the brain that is considered the control center of memory. It shrinks early and severely in Alzheimer’s disease,” explained Tommaso Ballarini, PhD, postdoctoral fellow in Michael Wagner’s research group and lead author of the study.
Continuation of nutrition study is planned
“It is possible that the Mediterranean diet protects the brain from protein deposits and brain atrophy that can cause memory loss and dementia. Our study hints at this,” 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.
Mediterranean Diet, Alzheimer Disease Biomarkers and Brain Atrophy in Old Age, Ballarini et al., Neurology® (May 2021), DOI: https://doi.org/10.1212/WNL.0000000000012067,
About Deutsches Zentrum für Neurodegenerative Erkrankungen (German Center for Neurodegenerative Diseases, DZNE)
The DZNE investigates all aspects of neurodegenerative diseases (such as Alzheimer’s and Parkinson’s and Amyotrophic lateral sclerosis) in order to develop novel approaches of prevention, treatment, and health care. It is comprised of ten sites across Germany and cooperates closely with universities, university hospitals, and other research institutions on a national and international level. The DZNE is a member of the Helmholtz Association of German Research Centers. Website: http://www.dzne.de/en
Here is another report
News Release 5-May-2021
Does eating a Mediterranean diet protect against memory loss and dementia?
American Academy of Neurology
MINNEAPOLIS – Eating a Mediterranean diet that is rich in fish, vegetables and olive oil may protect your brain from protein build up and shrinkage that can lead to Alzheimer’s disease, according to a new study. The research is published in the May 5, 2021, online issue of Neurology®, the medical journal of the American Academy of Neurology.
The study looked at abnormal proteins called amyloid and tau. Amyloid is a protein that forms into plaques, while tau is a protein that forms into tangles. Both are found in the brains of people with Alzheimer’s disease but may also be found in the brains of older people with normal cognition.
The Mediterranean diet includes high intake of vegetables, legumes, fruits, cereals, fish and monounsaturated fatty acids such as olive oil, and low intake of saturated fatty acids, dairy products and meat.
“Our study suggests that eating a diet that’s high in unsaturated fats, fish, fruits and vegetables, and low in dairy and red meat may actually protect your brain from the protein build-up that can lead to memory loss and dementia,” said study author Tommaso Ballarini, Ph.D., of the German Center for Neurodegenerative Diseases (DZNE) in Bonn, Germany. “These results add to the body of evidence that show what you eat may influence your memory skills later on.”
The study looked at 512 people. Of those, 169 were cognitively normal, while 343 were identified as being at higher risk of developing Alzheimer’s disease.
Researchers looked at how closely people followed the Mediterranean diet based on their answers to a questionnaire asking how much they ate of 148 items over the previous month. People who often ate healthy foods typical of the Mediterranean diet, like fish, vegetables and fruit, and only occasionally ate foods non-typical of the Mediterranean diet, like red meat, received the highest scores, for a maximum score of nine.
Cognitive skills were assessed with an extensive test set for Alzheimer’s disease progression that looked at five different functions, including language, memory and executive function. All the participants had brain scans to determine their brain volume. In addition, the spinal fluid of 226 was tested for amyloid and tau protein biomarkers.
Researchers then looked at how closely someone followed the Mediterranean diet, and the relationship to both their brain volume, tau and amyloid biomarkers, and cognitive skills.
After adjusting for factors like age, sex and education, researchers found that in the area of the brain most closely associated with Alzheimer’s disease, every point lower people scored on the Mediterranean diet scale was equal to almost one year of brain aging.
When looking at amyloid and tau in people’s spinal fluid, those who did not follow the diet closely had higher levels of biomarkers of amyloid and tau pathology than those who did.
When it came to a test of memory, people who did not follow the diet closely scored worse than those who did.
“More research is needed to show the mechanism by which a Mediterranean diet protects the brain from protein build up and loss of brain function, but findings suggest that people may reduce their risk for developing Alzheimer’s by incorporating more elements of the Mediterranean diet into their daily diets,” Ballarini said.
A limitation of the study is the fact that people’s diets were self-reported in the questionnaire. People may have made errors recalling exactly what and how much they ate.
Renee Tessman, [email protected], (612) 928-6137
M.A. Rosko, [email protected], (612) 928-6169
The study was supported by the German Center for Neurodegenerative Diseases and the German Federal Ministry of Education and Research.
Learn more about Alzheimer’s disease at BrainandLife.org, home of the American Academy of Neurology’s free patient and caregiver magazine focused on the intersection of neurologic disease and brain health. Follow Brain & Life® on Facebook, Twitter and Instagram.
When posting to social media channels about this research, we encourage you to use the hashtags #Neurology and #AANscience.
The American Academy of Neurology is the world’s largest association of neurologists and neuroscience professionals, with over 36,000 members. The AAN is dedicated to promoting the highest quality patient-centered neurologic care. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer’s disease, stroke, migraine, multiple sclerosis, concussion, Parkinson’s disease and epilepsy.
For more information about the American Academy of Neurology, visit AAN.com or find us on Facebook, Twitter, Instagram, LinkedIn and YouTube.