Having relatives with dementia might make you worry there’s some sort of ticking genetic time bomb dictating you too might someday be afflicted. But a growing body of research says you may be able to breathe easy.
These studies indicate that how we live plays a greater role than our genes in determining brain health as we age. In particular, what we eat and whether we’re obese could be crucial to our risk factors.
“For years, scientists thought that Alzheimer’s was primarily genetic,” said Gary Wenk, professor of neuroscience at Ohio State University. “We now believe that, while there’s a genetic component, Alzheimer’s is primarily a lifestyle disease.”
Although there are genes, such as APOE-4, that can predispose people toward the disease, whether or not those genes are activated depends largely on us, said Dr. Stuart Lipton, professor at Sanford-Burnham Research Institute, where he’s scientific director of neuroscience, aging and stem-cell research.
“A myth exists that if the Alzheimer’s gene is in your family, you’re going to get it. But that only affects one per cent of cases,” he said. “What matters most is how you superimpose your lifestyle on top of your genetic background.”
Ira Goodman, a neurologist at Orlando Health, said obesity is linked to Alzheimer’s because it’s a risk factor for diabetes. Diabetics have a two to three times greater risk of developing Alzheimer’s, Dr. Goodman says, because the “impaired ability to use or make insulin contributes to neurodegeneration.”
In addition, stress can play a factor in our brain health, because stress increases cortisol, a hormone that increases blood sugar — which also increases insulin.
Of course, the one thing we can’t do anything about is getting older. Currently, the chances of having Alzheimer’s by the time a person reaches age 85 is 50 percent, Goodman said, and that risk rises to 75 percent by age 100.
Still, he added, “Even if you do carry a genetic predisposition, lifestyle modifications in mid-life can greatly reduce the risk and delay onset.”