Does obesity make our brain shrink?

An increased amount of fat in the body is associated with a smaller brain

How does it affect our brains when we are overweight or obese? Researchers have now found that people with higher BMI and larger fat deposits around the midsection of the body have smaller brains compared to people of normal weight. The decrease in brain size increases linearly the more fat is present around the center of the body.

The scientists at Loughborough University in England found in her recent research that increased fat around the midsection of the body is associated with reduced brain volume. The physicians published the results of their study in the English-language journal "Neurology".

What is the gray matter in our brain?

If you are overweight or obese and have a lot of fat around the middle of your body, it could reduce the amount of gray matter in your brain. The so-called gray matter contains the majority of the brain's 100 billion nerve cells, while the white matter is filled with nerve fibers that connect the brain's regions. Previous studies have already uncovered links between gray matter atrophy and the risk of dementia, says study author Mark Hamer, a professor at Loughborough University.

One in five participants in the study was obese

In the study, the body mass index (BMI) and the waist-to-hip ratio were measured in 9,652 middle-aged subjects. A BMI between 18.5 and 24.9 is considered healthy, while a BMI over 30 is considered obese. The study also evaluated the waist-to-hip ratio, a high score of over 0.90 in men and over 0.85 in women means that a person has a high belly fat percentage or stomach than the hips. Based on these criteria, almost every fifth participant in the study was found to be obese.

With the help of magnetic resonance imaging (MRI) also the brain volume of the subjects was examined. Data evaluation took into account factors such as age, physical activity, smoking and high blood pressure, which can lead to a reduction in brain volume. The results of the study showed that people with higher scores had the lowest volume of gray matter in both BMI and waist-to-hip ratios. The decrease in brain size increases linearly, the greater the fat content in the middle part of the body, says Professor Hamer.

What could the doctors notice??

1,291 subjects with a BMI of 30 or higher and a high waist-to-hip ratio had the lowest average gray matter volume of 786 cubic centimeters. 514 persons with a BMI of 30 or higher, but without central obesity, had an average gray matter volume of 793 cubic centimeters. 3,025 participants with healthy values ​​had an average gray matter volume of 798 cc. There were no significant differences in white matter brain volume associated with obesity. Too much weight, however, was associated with gray matter shrinkage in four regions of the brain. It is unclear whether abnormalities in the brain structure lead to obesity or whether obesity leads to these changes in the brain, explains Professor Hamer.

Further research is needed

People with obesity and those with a higher waist-to-hip ratio (a marker of visceral fat around the abdomen) had lower levels of gray matter. This association between reduced brain volume and abdominal fat may indicate that inflammation and vascular factors are involved. Future research should investigate inflammation, nutrition and vascular health to better understand possible associations between brain health and obesity. Obesity can negatively impact a variety of health parameters. People should therefore strive to maintain a normal body weight, sums up Professor Hamer. (As)