What that extra 10 pounds is doing to your brain
Posted August 17, 2016
That extra 10 pounds may be around your middle, but it will affect your brain by middle age, researchers at the University of Cambridge in London say.
They scanned the brains of 473 people and found that those who were normal weight had larger brains than people who were overweight, The Telegraph reported.
The brains of overweight 50-year-olds looked like the brains of people who were 60. The researchers don't know why but speculate that the brain may be vulnerable to shrinkage during middle age.
It could also be that there's a genetic link between brain shrinkage and obesity, or that brain changes lead to overeating, another British newspaper, The Guardian, reported.
More research is needed to see if the differences hold over time, the authors said. "It will also be important to find out whether these changes could be reversible with weight loss, which may well be the case," Dr. Paul Fletcher, a professor of neuroscience at the University of Cambridge, told Laura Donnelly, The Telegraph's health editor.
There was one bit of good news: Although a shrinking brain is linked to Alzheimer's disease and other forms of dementia, the overweight people did not show signs of cognitive decline, as in a 2011 study.
A study of NFL football players led by Dr. Daniel Amen found that overweight men performed worse than normal-weight players on tests of attention, memory and general cognition. They also had decreased blood flow in the parts of the brain associated with attention and reasoning.
Amen concluded that blood flow to key areas of the brain as body mass increases, and decreased blood flow could affect cognition.
Another study in 2011, this one conducted on the offspring of people who participated in the renowned Framingham Heart Study in Massachusetts, found obesity linked to brain shrinkage, along with three other factors: high blood pressure, diabetes and cigarette smoking.
There's conflicting evidence on the link between obesity and Alzheimer's disease, however. A study of nearly 2 million people in Britain published in 2015 found that underweight people had a greater risk of the disease.
The researchers admitted to being surprised by the findings and speculated that nutritional deficiencies — particularly vitamin D and E — could be responsible.
“The relationship between obesity and dementia is complex and studies on the subject have shown contradictory results," Dr. James Pickett, head of research at the Alzheimer's Society in the UK, acknowledged in The Guardian's report.
“The jury is still out regarding any potential links between obesity and risk of memory loss and dementia, but we do know that what is good for the heart is also good for the head. Evidence shows that the best ways to reduce your risk of dementia include following a healthy diet, taking plenty of exercise and stopping smoking," he said.