Posted by dj on February 20, 2001, at 17:54:29
February 20, 2001
Fatheads indeed: Study says junky diet clogs brain
Tom Arnold
National Post
People on high-fat diets are not only increasing their risk of heart disease, they might also be damaging the learning and memory areas of their brain.A study by researchers at the University of Toronto and the Baycrest Centre for Geriatric Care compared the cognitive function of rats fed a high-fat diet -- similar to what humans consume if they do not eat nutritiously -- with rats on a lower-fat diet. After three months, the high-fat rats showed severe impairment on a wide range of learning and memory tasks. The findings also showed that giving glucose to the high-fat rats significantly improved their memory.
The findings are published in the March issue of Neurobiology of Learning and Memory.
"More and more, there are indications from a human perspective that chronic intake of high-fat diets is associated with cognitive deficits," said one of the authors, Dr. Carol Greenwood, a nutritional sciences professor at the University of Toronto and a research scientist at Baycrest Centre. "Our brain needs glucose in order to function. When glucose metabolism is impeded by saturated fatty acids, it's like clogging the brain and starving it of energy."
People may want to reconsider one of the most popular weight-loss programs today, a high-fat, low-carbohydrate diet, she said. The diet encourages people to eat bacon, pork, steak, butter, cheese, nuts and other high-fat, high-protein foods, and to avoid carbohydrates, including pasta, breads, cereal, sweets, some starchy vegetables and many fruits.
"What this data is showing is that, from a cognitive perspective, that is probably not an ideal diet," she said.
Chronic consumption of a high- fat diet affects declarative memory, or one's ability to consciously recall facts, such as remembering a telephone number, she said.
In a high-fat diet, fat normally comprises about 40% of 2,000 consumed calories a day. It is equivalent to 90 grams of fat.
A single container of regular yogourt contains eight grams of fat, as does a cup of homogenized milk. About two teaspoons of butter or margarine -- the average for two pieces of toast -- amounts to 10 grams of fat. A bag of 12 potato chips, two chocolate-chip cookies, a quarter of a box of Kraft Dinner or a single serving of microwave popcorn with butter each contains 10 grams of fat. One cup of a cream chowder soup or one-half cup of ice cream contains 15 grams of fat. A serving of peanut butter, about two tablespoons, totals 18 grams of fat.
Dr. Greenwood encourages a lower intake of fat for Canadians, to about 30% of 2,000 calories a day, or 65 grams of fat.
Dr. Greenwood completed the research with Dr. Gordon Winocur, a psychology professor at the University of Toronto and also a senior scientist at Baycrest Centre.
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