The bigger the belly, the more severe the brain atrophy! It may also increase the risk of dementia, and the latest research is doubly heart-wrenching
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Who would have thought that belly fat would also affect the brain!?
A new study from nearly 10 scientific research institutions, including the University of Washington, pointed out:
Thick belly fat is associated with a decrease in brain volume.
And the bigger the belly, the more severe the brain atrophy is likely to be, and it also increases the risk of dementia.
This is more severe in women.
The study has been published in the geriatric journal Aging and Disease.
(Very good, the motivation to lose weight has increased again)
How exactly did the researchers come to this conclusion?
MRIs were performed on 10,001 healthy people
To investigate the relationship between abdominal fat (visceral fat and subcutaneous fat) and structural changes in the brain, researchers from the University of Washington in the United States performed whole-body magnetic resonance imaging (MRI) examinations on 10,001 healthy participants.
The participants ranged in age from 18-90 years, with an average of 52.9 years.
Next, the researchers used a deep learning model to automatically identify and segment the contours of the body's internal organs and the location of the body's adipose tissue in the MRI images, and calculate the volume of each person's visceral fat and subcutaneous fat.
The medical criterion for determining obesity is body mass index (BMI) (weight÷ height^2).
After calculation, the researchers recorded that the average visceral fat volume of overweight (BMI≥25) people was 3417.81±514.88ml; The average visceral fat volume of the obese (BMI≥30) population was 5355.24±505.04ml.
The volume of brain regions was also measured using deep learning methods, using the FastSurfer convolutional neural network to segment 96 different brain regions.
△ Brain volume fractionation results
Considering the differences in head size among the different participants, the researchers also used a separate deep learning model to segment the intracranial volume.
They manually labeled the intracranial compartments (a series of ventricles within the skull) of 60 participants, and then used this data to train nnUNet, a deep learning framework for medical image analysis, to generate an intracranial mask (a three-layer membrane that covers the inside of the skull and encloses and protects the central nervous system).
With a series of data available, the researchers then used linear regression, logistic regression and other statistical methods to analyze the quantitative relationship between each person's abdominal fat volume and the volume of different parts of their brain.
In the end, the following conclusions were drawn:
The higher the content of abdominal viscera and subcutaneous fat, the smaller the volume of total gray matter and total white matter in the overall brain tissue.
(Gray matter is a collection of gray nerve cell bodies and neurons in the brain, which are closely related to thinking, perception, and motor control, etc.; White matter is made up of bundles of neuronal fibers that are responsible for transmitting information. ）
The correlation coefficient between visceral fat and total gray matter volume was r=-0.44, p
(r is in the range of [-1,1], where being equal to -1 means a complete negative correlation, being equal to 1 means being completely positively correlated, and 0 being unrelated; p
△ Relationship between increased visceral fat and decreased gray matter (left) and white matter (right) volume
Specific to the cerebral lobes, the frontal, temporal, parietal and occipital lobes all atrophied with the increase of abdominal fat, and the temporal lobe relationship was more significant, with a correlation coefficient of r=-0.44. Cerebellar volume was also affected, r=-0.4.
In addition, as shown in the figure below, subcutaneous fat (Sfat) has a stronger relationship with brain volume loss than visceral fat (Vfat) and has a higher beta value.
After analyzing by sex, they also found that the relationship between brain volume and abdominal fat was more significant in female participants, with correlation coefficients of -0.55 and -0.52, respectively.
△ It is more pronounced in women
Let's take a look at the MRI of two 61-year-old women, the one on the left has high levels of visceral fat and subcutaneous fat, and the one on the right is normal. It can be clearly seen that the brain volume of the person on the left is smaller than that of the person on the right, which is manifested by the enlargement of the ventricles and the widening of the sulcus gyrus.
△ Example of brain volume reduction with high body fat
The researchers further analyzed brain regions associated with early Alzheimer's pathology and came to a similar conclusion:
The volume of hippocampus, posterior cingulate gyrus, and precuneus decreased with the increase of visceral fat, and was more significant in women.
Logistic regression analysis also found that the risk of total gray matter and white matter atrophy was different in different age groups.
For people aged 20-39 years, people with high abdominal fat are 5.9 times more likely to have total gray matter atrophy than people with normal fat levels, 40-59 years old are 5.4 times more likely, and 60-80 years old are 5.1 times more likely to have total gray matter atrophy.
Looking at white matter atrophy, people aged 20-39 years old have 3.78 times the probability of total white matter atrophy in people with high abdominal fat than people with normal fat levels, 4.4 times the probability of 40-59 years old, and 5.1 times the probability of 60-80 years old.
Being overweight may also lead to cognitive decline
In fact, a number of studies have shown that belly fat can affect the brain.
For example, the following study found that obesity and Alzheimer's disease cause gray matter atrophy in similar ways.
A study published in JAMA Network Open also found a significant positive correlation between visceral fat content and cognitive impairment.
The Lancet also recently published a study that concluded that sounds more shrimpy:
For every 0.27kg increase in visceral fat, the cognitive age ages by 0.7 years.
This is simply double the heart.
Paper link: https://pubmed.ncbi.nlm.nih.gov/37728587/