| |
 |
Cream cakes can harm brains
|
奶油蛋糕可使青少年大脑堵塞
HAMBURGERS and cream cakes do not just clog(堵塞) arteries(动脉), they also produce flabby(软弱) minds.
Two scientists at Toronto University discovered that too much fat during childhood and adolescence(青春期) impaired memory and concentration by preventing the brain taking up the glucose(葡萄糖) needed for healthy performance.
Although the study was carried out on rats, the two scientists said it had implications for adolescent humans. Gordon Winocur, a professor of psychiatry, and Carol Greenwood, a professor of nutrition, said teenagers who ate fatty(油腻的) foods might suffer permanent damage to their developing brains.
The two scientists fed one-month-old rats a diet rich in either animal or vegetable fat. This continued until they were four months old, the equivalent of late adolescence in humans. Forty per cent of the rats' intake of calories came from fat, but otherwise their diet was nutritionally complete. A group of controlled rats were fed the standard laboratory diet, in which only 10 per cent of the calories came from fat.
Once they reached four months, the rats were taught a task in which they had to learn that they would get a food pellet(丸) only if they pressed a lever every second time they were shown it.
Some rats quickly learned that pressing every time was pointless, but others were unable to remember if they had pressed the lever the last time it had appeared. The delay could be up to 80 seconds, a long time for a hungry rat. Rats on either type of high-fat diet performed much worse than the rats fed a lean diet, New Scientist reported.
“High-fat diets impair performance on virtually all our measures. It's remarkable how impaired these animals are," said Prof Winocur. “When high-fat rats were injected with glucose, their cognitive function improved."
The researchers believe the fat prevents the brain taking up glucose, possibly by interfering with the action of insulin, which helps regulate blood sugar levels. High-fat diets often cause insulin resistance and some people with signs of adult-onset diabetes, often caused by obesity, are known to have memory problems.
Many adolescent children get 40 per cent of their calories from fat, Prof Winocur added. He was concerned that developing neural pathways could be permanently damaged at that age. “And maybe the developing brain is much more susceptible than the older brain," he said.
March 1, 2001
The Daily Telegraph
|
|
|
|
