Although the brain is still unexplored human organ, there are indications that what may be good for the heart may also be good for the brain.
It’s been long known that large waists carry a risk of heart disease. New research done by some US researchers show that a big waistline in those over 40 almost triples the risks of cognitive decline i.e. dementia.
Obesity has been previously linked with Alzheimer's disease, the most common form of dementia.

New results show that it matters where one carries the weight to be an important predictor for dementia risk. Even people with normal weights but large waists were found to be at greater risk of this brain malfunctioning.

However, the research that included 6,500 people found obesity and large waistlines to be the most dangerous combination. A large waist size was a good guide to future health problems.

Although still not revealed precisely why and how being overweight affects the ageing brain, many specialists feel that associated problems such as high blood pressure, diabetes and high cholesterol levels may be to blame. Thickness of fat around the waist is thought to correspond closely with its presence around the major organs of the body.

Researchers looked at 6,583 people between 40 and 45 years of age and measured their abdominal fat levels with calipers. The study participants were then followed into their 70s to see who became ill, and who managed to maintain relatively good health.

It was found that 20% of people with the largest waistlines had a 270% greater risk of dementia than those with the smallest waists. Even those with normal weights and large waists had approximately a 90% increased risk of dementia. Being overweight with a large waist raised the risk by 230% while being obese with a large waist showed 360% rise in dementia risk.

Some of the researchers said that these results are not surprising because large abdomens are associated with high blood pressure, cholesterol and diabetes - all being major risk factors for dementia.

Scientists are hoping that further studies will confirm these findings and help reveal how dementia develops. It is known now that changes in the brain related to the Alzheimer's disease start to appear long before any symptoms became evident.