50+ health * Mental wellbeing

Obese at greater risk of Alzheimer's

Obesity is bad for you Close link between weight and cognitive impairment

The obese and the overweight are at greater risk of Alzheimer's disease, new research has found.

The study compared the brains of the obese, the overweight, and those of normal weight. It found that the obese have 8% less brain tissue than people of normal weight, while the overweight have 4% less tissue.

"That's a big loss of tissue and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer's and other diseases that attack the brain," said researcher Dr Paul Thompson of the University of California Los Angeles.

Alzheimer's is the most common form of dementia. It is incurable and degenerative, and is generally diagnosed in people over the age of 65.

The study found that the obese had lost brain tissue in areas of the brain critical for planning and memory, attention and executive functions, long term memory and movement. There was similar, but lesser cognitive impairment in the overweight.

"The brains of obese people looked 16 years older than the brains of those who were lean, and in people they looked eight years older," said Dr Thompson.

Being obese puts you at risk of developing cardiovascular disease, diabetes, and hypertension, among other conditions.

"It seems that along with increased risk for health problems such as type 2 diabetes and heart disease, obesity is bad for your brain: we have linked it to shrinkage of brain areas that are also targeted by Alzheimer's," said lead author Cyrus A. Raji, from the University of Pittsburgh School of Medicine.

"But that could mean exercising, eating right and keeping weight under control can maintain brain health with ageing and potentially lower the risk for Alzheimer's and other dementias," Mr Raji added.

The research was published in the current online edition of the journal Human Brain Mapping.

This article was published on Wed 26 August 2009

Image © Sheila Eames - Fotolia.com

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