The Connection Between Diabetes and Alzheimers

When it comes to keeping the brain healthy, putting on extra weight could be far riskier than most people have imagined. Scientific findings, some released within the past two years, indicate that weight gain and type 2 diabetes might trigger degenerative changes in the brain and very possibly Alzheimer's, says Marilyn Albert, an Alzheimer's expert at Johns Hopkins University in Baltimore.

Up to 16 million people will get Alzheimer's by 2050, experts believe. That projection could increase if the rates of obesity and diabetes don't start to come down, says Zoe Arvanitakis, a neurologist at Rush University Medical Center in Chicago. "There are more and more people with type 2 diabetes. We're going to see more and more people with dementia, including Alzheimer's."

Many factors cause Alzheimer's, so losing weight doesn't offer any guarantee of a senility-free old age. But people who lose weight or control their diabetes might be able to keep aging brain cells in top shape as long as possible, experts say.

Then, if Alzheimer's does set in later in life, the process might be slower than usual, and people might die of another cause before they develop any sign of Alzheimer's, says Gregory Cole, a researcher at the University of California at Los Angeles. "If you're going to get the disease when you are 80, and you delay it by 10 years, you have a pretty good chance of not getting it at all," Cole says.

The evidence linking diabetes and Alzheimer's includes a Chicago study of 842 older Catholic nuns, priests and brothers. None had any sign of Alzheimer's at the start, but during the nine-year study, 151 developed Alzheimer's.

People who had type 2 diabetes had a 65% increased risk of getting Alzheimer's, according to a statistical analysis. The findings were published in the Archives of Neurology last year.

Here's the scenario suggested by the study: Weight gain triggers insulin resistance, a condition in which cells don't respond to the hormone insulin. Normally, insulin helps transport sugar into cells, where it is used for fuel.

But when insulin resistance develops, cells don't get enough sugar. As time goes by, insulin resistance can lead to type 2 diabetes, and the lack of sugar might cause brain cells to malfunction or die, Cole says. Dying brain cells may set the stage for Alzheimer's.

The whole process may be kicked off by a high-fat diet. Food that's easy to grab and eat, especially fast food, contains lots of saturated fat that can clog blood vessels.

Up to 75% of Americans older than 50 have insulin resistance, an often silent condition that puts them at risk of having a heart attack, a stroke and possibly Alzheimer's.

Take these steps to lower the risk:

If you're overweight, lose some of the extra fat. Even a modest weight loss of 10 pounds can improve or even prevent insulin resistance.

Walk, bike, run or build more activity into daily life. Exercise helps insulin work better.

Eat a healthful, low-fat diet, one that contains whole grains, fruits and vegetables and fish. Fish contains omega-3 fatty acids, a beneficial fat that might lower the risk of Alzheimer's.

Sources: The Alzheimer's Association and Francine Kaufman, past president of the American Diabetes Association and author of Diabesity: The Obesity-Diabetes Epidemic that Threatens American and What We Must Do to Stop It.