December 29, 2008
Junk food high in fat, cholesterol and sugar could hasten the onset of Alzheimer's, new research suggest. Those are the findings in mice from new research out of Europe showing that the typical fast-food diet is bad for the brain.
Scientists at the Karolinska Institute, a medical university in Sweden, studied mice that were bred to develop a predisposition to a disease resembling Alzheimer's in people. The mice carried a gene that resembles the APOE-E4, for apolipoprotein E, gene in people. People who carry this gene, which regulates the transport of cholesterol in the body, have an increased risk of Alzheimer's. But carrying the gene does not guarantee that someone will become demented and many people with Alzheimer's do not have the E4 gene.
The current research showed that after nine months, the mice eating a fatty, sugar-rich diet developed brain defects that resembled those that occur in people with Alzheimer's.
"On examining the brains of these mice, we found a chemical change not unlike that found in the Alzheimer brain," said Susanne Akterin, a doctoral student at the institute's Alzheimer's Disease Research Center on whose research the findings are based.
Mice eating the fast-food diet had changes in a protein called tau in the brain. In people, the tau protein is part of the system that carries nutrients to brain cells. But once the tau protein is damaged, as in Alzheimer's, it forms rope-like bundles called tangles that leand to brain cell death.
"We now suspect that a high intake of fat and cholesterol in combination with genetic factors, such as APOE-E4, can adversely affect several brain substances, which can be a contributory factor in the development of Alzheimer's," Ms. Akterin said.
Earlier research has linked high cholesterol to an increased risk for Alzheimer's disease. A large study from Finland earlier this year, for example, showed that men and women with high cholesterol in their 40s were more likely to develop Alzheimer's than those with low cholesterol. High cholesterol has also been linked to cardiovascular disease and may damage the blood vessels that nourish the brain.
Furthermore, a super-sized, high-calorie, fast-food diet rich in fat and sugar is also likely to lead to obesity. A growing body of evidence links obesity in middle age to memory problems or Alzheimer's in old age.
Scientists also speculate that fat cells may produce harmful chemicals that promote inflammation in blood vessels throughout the body, including the brain. People who are overweight may also tend to have diets low in"good" fats, such as those found in fish, and to get less exercise than those who are of normal weight, factors that may increase Alzheimer's risk.
Experts agree that keeping cholesterol and weight at a healthy level is good for the heart -- and the brain. A diet low in animal fats and other saturated fats, but high in fiber, can help keep cholesterol levels down. Regular exercise, and keeping weight down, can also help. In addition, moderate consumption of red wine or alcohol, just one glass a day, may help the heart and brain.
More and more Americans both young and old are becoming obese and eating poorly. We must all learn to maintain healthy lifestyles as a way of preserving our brains. Learn more about risk factors for Alzheimer's disease and how to maintain your brain at www.ALZinfo.org.
Source: The Karolinska Institute, Sweden.