How Diabetes Can Affect Your Brain

Medically reviewed in September 2021

There’s a reason Sam Gandy, MD, PhD, was dubbed a “Rock Star of Science” by GQ magazine a few years back. Dr. Gandy, professor of neurology and psychiatry at New York City’s Mount Sinai School of Medicine, uncovered a major clue in a mystery that has long puzzled doctors: Why are people with type 2 diabetes up to three times more likely to develop Alzheimer’s disease? For the nearly 26 million Americans who have diabetes, Dr. Gandy’s answer could be a compelling reason to follow some old, standard advice.

Sharecare talked to Dr. Gandy and got the latest.

The Diabetes-Alzheimer’s Connection: Diabetes and Alzheimer’s disease seem to have little in common. Type 2 diabetes starts to develop when the body stops using the hormone insulin efficiently, a condition known as insulin resistance. The cause of Alzheimer’s disease is still being studied, but a key culprit appears to be a sticky substance called amyloid that builds up in the brain and interferes with communication between cells.

By studying mice, Dr. Gandy and his colleagues made a stunning discovery: The gene that controls for insulin resistance also regulates the production of amyloid. When the gene is missing or doesn’t work as it should, the risk for diabetes goes up – and so does the level of amyloid in the brain. Sure enough, mice that Dr. Gandy’s team bred to lack the gene had learning and memory problems. Dr. Gandy believes this breakthrough could help scientists develop new medications for preventing and treating Alzheimer’s disease, which afflicts about 5 million Americans.

Takeaway Advice: Get plenty of exercise. It’s a must for managing type 2 diabetes, but physical activity keeps the brain healthy, too. Jogging, tennis, and any form of exercise gives your thinking muscle a serious workout. “It takes an enormous amount of brain activity to coordinate physical movement,” says Dr. Gandy. What’s more, exercise triggers the brain to produce new neurons, or nerve cells, which can replace old, damaged ones.

Gandy’s Prediction: Brain scans for early signs of Alzheimer’s will become available in the not-to-distant future. In fact, the scans will be as common as screening tests such as mammograms and colonoscopies. “Hopefully, by then we’ll have effective interventions and be able to prevent Alzheimer’s from ever happening,” he says.

Call to Action: Write your congressional representative and ask for more funding for Alzheimer’s research. “Alzheimer’s research is underfunded,” says Dr. Gandy, noting that much more money is spent studying other diseases that will afflict far fewer people.

Oddball Fact: When Dr. Gandy was photographed for GQ with several other scientists and will i. am of the Black Eyed Peas, the photographer asked Gandy, who is right-handed, to snap his fingers with his left hand. Says Dr. Gandy: “Everyone in the picture is laughing because I had such a hard time getting the beat with my left hand.”

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