A diet high in processed fructose may impair the brain’s ability to heal after head trauma, according to a new rat study by neuroscientists at the University of California, Los Angeles (UCLA).
“Americans consume most of their fructose from processed foods sweetened with high-fructose corn syrup,” said Dr. Fernando Gomez-Pinilla, a professor of neurosurgery and integrative biology and physiology at UCLA’s David Geffen School of Medicine. “We found that processed fructose inflicts surprisingly harmful effects on the brain’s ability to repair itself after a head trauma.”
Although fructose occurs naturally in fruit, the inherent antioxidants, fiber, and other nutrients in the whole fruit prevent the same damage.
The findings add to the mounting evidence of the direct connection between nutrition and brain health. According to the Centers for Disease Control and Prevention, an estimated 1.7 million people suffer with traumatic brain injury (TBI) each year, resulting in 52,000 annual deaths.
For the study, laboratory rats were fed standard rat food and trained for five days to navigate a maze. Then they were randomly assigned to a group that was fed plain water or a group that was fed fructose-infused water for six weeks. The fructose was crystallized from corn in a dose simulating a human diet high in foods and drinks sweetened with high-fructose corn syrup.
A week later, the rats were anesthetized and underwent a brief pulse of fluid to the head to mimic the effects of human traumatic brain injury. After an additional six weeks, the researchers retested all the rats’ ability to recall the route and escape the maze.
The results were significant: the rats on the fructose diet took 30 percent longer to find the exit compared to those who drank plain water.
The fructose altered a wealth of biological processes in the animals’ brains after trauma. The sweetener interfered with the ability of neurons to communicate with each other, rewire connections after injury, record memories and produce enough energy to fuel basic functions.
“Our findings suggest that fructose disrupts plasticity — the creation of fresh pathways between brain cells that occurs when we learn or experience something new,” said Gomez-Pinilla, a member of the UCLA Brain Injury Research Center.
“That’s a huge obstacle for anyone to overcome — but especially for a TBI patient, who is often struggling to relearn daily routines and how to care for himself or herself.”
Prior studies have shown how fructose harms the body through its role in contributing to cancer, diabetes, obesity, and fatty liver. Gomez-Pinilla’s research is the latest in a UCLA body of work revealing the effects of fructose on brain function. Previously, his team was also the first to identify the negative impact fructose has on learning and memory.
“Our take-home message can be boiled down to this: Reduce fructose in your diet if you want to protect your brain,” Gomez-Pinilla stressed.
Made from corn starch, high fructose corn syrup is widely added as a sweetener and preservative to processed foods, soft drinks, condiments, applesauce, and baby food.
The average American consumed roughly 27 pounds of high-fructose corn syrup in 2014 — or just under eight teaspoons per day, according to the U.S. Department of Agriculture. That’s a drop from a decade ago, when Americans consumed more than 36 pounds of the syrup per year.
The findings are published in the Journal of Cerebral Blood Flow and Metabolism.