Researchers found that gastric bypass patients, when tested six months after their weight-loss surgeries, had less expression of genes that are thought to be precursors of the debris that clogs the brains of people with Alzheimer's disease.
"Our study shows for the first time that weight loss resulting from bariatric surgery leads to a reduction in the expression of genes related to Alzheimer's disease," study author Dr Paresh Dandona, a professor at State University of New York at Buffalo, said.
Research presented at meetings should be viewed as preliminary because it has not been subjected to the same level of scrutiny as studies published in most medical journals.
Obese diabetics and Alzheimer's disease risk
In the study, the researchers analysed the blood of 15 patients with type 2 diabetes who underwent weight-loss surgery and lost an average of about 86 pounds over six months. Compared to before the surgery, the patients' expression of amyloid precursor protein fell by 22%, and the researchers also noticed less expression of other genes that appear to be connected to Alzheimer's disease.
However, the study didn't examine the patients for signs of the disease, so there's no way to know if their risk actually went down.
Scientists think there's a link between obesity and diabetes, which appears to boost the risk of Alzheimer's disease, said Greg Cole, associate director of the Alzheimer's Center at the University of California, Los Angeles. He said obesity may boost inflammation in both the body and the brain.
"Weight loss is likely to improve health, but one caveat is that the epidemiology of weight loss is complicated," he added. "Weight loss in elderly people can be a harbinger of incipient dementia. Further, according to a National Institute on Aging study, there may be significant differences in the way in which changes in mid-life weight impact the risk for Alzheimer's: women who lose weight between 30 and 45 actually appear to be at increased risk."
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