New Study Finds Body Fat Linked to Brain Shrinkage
A recent study published in the journal “Neurology” connected body fat to brain shrinkage. While there is some precedent for similar findings, there is still more that we need to know.
What the Study Found
The UK study looked at nearly ten thousand people with an average age of fifty-five and found a correlation between their body fat content and the sizes of their brains.
Body fat content was measured using both Body Mass Index and Waist-to-hip ratios. Body Mass Index, or BMI, a ratio of a person’s weight to their height. While it is a good shorthand, it does not account for lean muscle mass.
The use of waist-to-hip ratios in conjunction with BMI gave a more accurate idea of the subjects’ body fat content. In addition to these metrics, subjects answered questions regarding other aspects of their health. Measuring fat in the abdominal region was also significant because this kind of body fat has been found to be more harmful to overall health, in part because it impedes the functioning of vital organs.
The size of the brain was determined using Magnetic Resonance Imaging. This diagnostic imaging technique did not only provide a size of the brains, but also allowed the researchers to differentiate between white matter and grey matter, the two main kinds of brain tissue. The study noted a particular difference in the amount of grey matter, the brain tissue responsible for higher-level functioning.
“Existing research has linked brain shrinkage to memory decline and a higher risk of dementia, but research on whether extra body fat is protective or detrimental to brain size has been inconclusive,” said Dr. Mark Hamer, lead author of the study. “Our research looked at a large group of people and found obesity, specifically around the middle, to be linked with brain size.”
How the Study Relates to Existing Research
Despite this link, the authors of the study did not suggest that excessive body fat causes brain shrinkage. The two most obvious potential conclusions are that body fat in some way causes a smaller brain and that a smaller brain somehow causes excessive body fat. The authors of the study said that further studies would be require to better understand the established link. That is not to say that this study is the first of its kind to reach these results.
Another study (Body mass index, but not vitamin D status, is associated with brain volume change in MS; Mowry et al) also published in Neurology but in December of last year linked a high BMI with a lower grey matter volume in people with multiple sclerosis, a degenerative muscle condition. Body weight has also been known to be associated with Alzheimer’s.
“We know there’s a link between obesity and dementia, so it’s not hugely surprising to see the results of this study showing obese people had slightly less grey matter, a risk factor for dementia,” Dr. James Picket, Head of Research at the Alzheimer’s Society said in a response to the study. “We don’t know what precisely links obesity, brain health, and risk of dementia, but it’s likely that poorer cardiovascular health plays a role.”
What the Findings Mean
Further research in this area is still required in order to make the most of this study. However, that doesn’t mean that the study is worthless right now. More than anything else perhaps, it serves as a reminder to keep body fat under control.
As Dr. Picket pointed out, excess body fat is linked not only to dementia but also to poor cardiovascular health. It also makes it more difficult to maintain muscle mass, balance, and flexibility as we age. As a result, the inconclusive results of this study are not a sufficient excuse to put off getting in better shape.