Scientists talked about the connection of diet with slowing down brain aging
In people whose diet was more in line with the principles of the MIND diet, the gray matter of the brain decreased more slowly with age. The researchers estimated the differences in this indicator as equivalent to a delay in age-related changes of about 2.5 years. The conclusion is based on long-term observation of more than 1.6 thousand people, but it does not prove that it was nutrition that caused this result. What is included in this diet and how to correctly understand the conclusions of scientists — in the material of Izvestia.
What is the MIND diet?
MIND combines elements of the Mediterranean diet and the DASH diet, designed to control blood pressure. It focuses on foods that researchers consider to be potentially beneficial to brain health.
MIND is an abbreviated name for a nutrition system aimed at slowing down neurodegenerative changes, that is, the gradual damage and loss of nerve cells.
The initial MIND assessment system also includes moderate wine consumption. However, the study in question does not establish the benefits of alcohol for the brain and does not provide grounds to recommend its use.
Previous studies have linked this diet to better memory and thinking performance. In the new analysis, the researchers focused on another issue.: how nutrition correlates with changes in brain structure over the years.
How scientists observed the brain
The researchers examined data from 1,647 participants in the Framingham Study, a long—running American health research project. The average age of people at the start was about 60 years.
Nutrition was assessed using questionnaires in which participants indicated how often they consumed different foods. Compliance with the MIND diet was expressed in points: the maximum result was 15, and the average in the study group was slightly less than seven.
Each participant had at least two magnetic resonance imaging brain scans conducted between 1999 and 2019. At the time of the first examination, they did not have a stroke or dementia. The duration of follow-up was about 12 years.
MRI allows you to compare the volume of different areas of the brain and see how it changes over time. It was these changes, rather than the participants' feelings or their assessment of their own memory, that became the basis of the analysis.
What does it mean to delay aging by 2.5 years?
As we age, the volume of some brain tissues gradually decreases. The study participants generally demonstrated this dynamic, but its speed varied. Each additional three points of compliance with the MIND diet were associated with a lower annual loss of gray matter — by about 0.279 cubic cm. According to the authors, this corresponded to a slowdown in the age-related decrease in its volume by about 20%.
Gray matter contains the bodies of nerve cells and is involved in information processing, memory, learning, and decision-making. Therefore, maintaining its volume is of interest for studying brain aging.
The indicator "2.5 years" was obtained by comparing the detected difference with the rate of age-related changes. It does not mean that the participants' brains have literally become younger or that the onset of dementia in each of them has been postponed for such a long time. We are talking about the calculated equivalent of differences in one structural indicator over the observation period.
In addition, higher MIND scores were associated with a slow increase in the ventricles of the brain. These are cavities filled with cerebrospinal fluid. As the surrounding brain tissue shrinks, they can expand. According to this indicator, the difference was estimated as the equivalent of a delay in age-related changes of about a year.
What products have the researchers identified?
More frequent consumption of berries was associated with a slow increase in the ventricles of the brain. A similar relationship was found for the bird, which was also associated with less loss of gray matter.
Sweets, on the other hand, were associated with faster ventricular expansion and a decrease in the hippocampus, an area of the brain important for memory formation. More frequent consumption of fried fast food was also accompanied by a greater loss of hippocampal volume.
The authors suggest that plant compounds in berries and other components of the diet may affect the processes of cell damage. However, the possible mechanisms need to be tested separately: in this work, scientists observed links between nutrition and MRI results.
Why the results were mixed
Some observations did not match expectations. Higher intake of whole grains was associated with less beneficial changes, including a rapid decrease in gray matter and the hippocampus.
The opposite pattern was found for cheese: its more frequent consumption was accompanied by a slow loss of volume of these tissues and less ventricular expansion.
These results do not allow us to declare whole—grain products harmful, and cheese as a means of protecting the brain. The analysis of individual foods in an observational study does not completely separate their influence from other dietary and lifestyle characteristics.
What research can and cannot prove
The people who followed the MIND principles better differed from the rest of the participants in other characteristics. They smoked less often, were less likely to have obesity, type 2 diabetes, high blood pressure and cardiovascular diseases.
The association between diet and beneficial brain changes was stronger in older, physically active participants and people without overweight or obesity. This indicates the importance of studying nutrition along with other lifestyle features.
"The study cannot prove a direct protective effect and did not evaluate the effect on memory or thinking," said Jackie Hanley, head of research at Alzheimer's Research UK, commenting on the work for the Science Media Center.
The authors also acknowledged the limitations of nutrition questionnaires: people may not accurately remember what they ate and how often. It was not possible to fully account for dietary changes over time, genetic factors, and possible mild cognitive impairment at the time of the first MRI scan. Most of the participants were white, so the results need to be checked in more diverse groups.
The work supports further exploration of MIND as a possible way to maintain brain health. However, studies should prove that changing the diet itself slows down age-related changes, in which participants are assigned different food options and then the results are compared.
Переведено сервисом «Яндекс Переводчик»
