Studies Show Glucose and Oxygen Help Brain

April 2, 2001 -- Got writer's block or can't seem to work through your data? Reaching for sugar or even an oxygen mask could help, suggests a new study by a British neuroscientist.

Just as athletes can benefit by eating right and doping their blood to contain more oxygenated cells, the new findings suggest students can improve their performance by eating glucose or breathing pure oxygen.

"We found a dose of oxygen or glucose can improve performance on tasks that require great mental effort," says Andrew Scholey, director of the Human Cognitive Neuroscience unit at the University of Northumbria in Newcastle, England.

Hungry Brain

Past research has shown that the brain is an energy-demanding organ. While it makes up only 2 percent of the body's weight, it consumes more than 20 percent of the body's energy. But Scholey explains the brain is incapable of storing significant amounts of glucose and requires blood flow to steady its supply. As mental strain increases, so too does the brain's demand for energy in the form of oxygen and glucose.

"We measured levels of glucose and oxygen while people were doing mental tasks and found both levels fell," Scholey says.

To conduct his tests, Scholey and his team first monitored students as they played the computer game Tetris. He found when the students played the game at beginner levels, doses of oxygen and glucose did not help the their scores. But as the players reached more challenging levels, the students showed significant improvement after sucking oxygen and drinking a sweet, lemon-flavored glucose drink.

Next Scholey's team quizzed students using a "serial seven" test. In the test students are given a number and then asked to subtract seven from the number and then from each subsequent number. Scholey found those who drank glucose could accomplish between two to three times more calculations per minute than those who did not take the glucose drink.

Judith Wurtman, a cognitive scientist at the Massachusetts Institute of Technology in Boston, says the findings agree with past research. Studies done in the 1970s showed that glucose can improve brain performance, particularly if a subject is feeling depressed or angry or distracted, by increasing the organ's ability to make more of the body's mood regulator, serotonin. Serotonin is a brain chemical known to elevate a person's state of mind.

Brain Air Freshener

The glucose may have helped the students in Scholey's studies, says Wurtman, by aiding in the production of serotonin in their brains. And, she adds that the concept of oxygen boosting the brain's performance only makes sense.

"Everyone has experienced the lethargic effect of riding in a plane with poor air circulation for four hours. It makes you mentally foggy," she says. "But I don't think breathing pure oxygen is a practical solution. Who wants to go into an exam with an oxygen tank on their back?"

Rather than breathing from an oxygen mask, Wurtman suggests taking a break to walk outside for some fresh air could enhance work performance.

In his next studies, Scholey hopes to zero in on the reported effects of herbal mental enhancements such as the herbal extract gingko. Gingko is thought to boost blood flow and speed up the breakdown of glucose. In his own studies, Scholey found students who were given a single dose of the extract demonstrated better acuity for up to six hours than students operating without the herbal extract.

"We hope to understand how interventions like gingko can improve oxygen and glucose in the blood and help deliver more to the brain over a longer period," he said.