At the University of Minnesota Medical School, neurosurgeon Andrew Venteicher and his team made an unexpected discovery: removing a rare brain tumor improved blood sugar control in patients with diabetes, sometimes dramatically and for years afterward.
The tumor in question—an olfactory groove meningioma—sits near the base of the brain where the two frontal lobes meet. These tumors are typically associated with neurological symptoms: blurred vision, shifts in personality, loss of smell. What surprised Venteicher's team was that after surgical removal, many patients with diabetes experienced something entirely different: sustained improvements in their ability to regulate blood glucose, even when they weren't taking additional diabetes medications.
The research, published in JAMA Network Open, tracked patients with both an olfactory groove meningioma and diabetes over five years following surgery. The team measured hemoglobin A1c (HbA1c), the standard clinical marker of long-term blood sugar control, and monitored body weight changes. The results were striking. Blood sugar control improved in most patients after tumor removal, with improvements often appearing soon after surgery and persisting for years. Many patients also lost weight without any documented changes to their diabetes medication regimens.
This finding opens a window into how the brain influences metabolism across the entire body—a connection that remains poorly understood in modern medicine. "What surprised us was how much blood sugar control improved after surgery in many of these patients," Venteicher said. The discovery suggests that certain brain tumors may actively interfere with the body's metabolic regulation, and that removing them can restore function in ways that extend far beyond typical neurological benefits.
The implications are significant. For patients living with diabetes—a condition affecting over 37 million Americans and requiring careful medication and lifestyle management—the possibility that brain surgery could independently improve blood sugar control raises new clinical questions. It also hints at deeper mechanisms: how exactly does a benign tumor pressing on the frontal lobes disrupt glucose metabolism? And might other brain tumors have similar metabolic effects?
Venteicher's team is already planning the next phase of research. They want to understand the biological mechanisms driving these improvements and investigate whether similar metabolic benefits occur after removing other types of brain tumors. The findings could eventually reshape how physicians counsel patients before surgery, helping them anticipate not just neurological improvements but metabolic ones as well.
For now, the study represents a small but meaningful expansion of how we understand the brain's role in whole-body health. It's a reminder that the nervous system is not siloed from metabolism and weight regulation—they're intricately connected. That connection, once mapped more clearly, might one day offer patients new pathways toward better health.