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Prevention of Chronic Disease
Much of the research discussed at the seminar had to do with addressing pathologies after they are well established in the body, but at least two of the scientists spoke passionately about their research on ways to prevent, or at least delay the onset of disease.
Walter Willett, Fredrick John Stare Professor of Epidemiology and Nutrition at Harvard School of Public Health, noted that cardiovascular disease continues to be the leading cause of death in the United States. For the last 20 years, the rates at which people died of stroke and heart disease have remained unchanged. However, with proper diet, Willett said, 82 percent of the heart disease identified in a large-scale study of female nurses could have been prevented.
In the 1960s, improved treatment, and initial changes in diet due to the discovery that saturated fats increased cholesterol and that poly-unsaturated fats helped decrease it, were responsible for an initial decline in the incidence of heart disease. But, Willett says, that trend has flattened out as people responded to advice from their doctors and from the federal government, which recommended low levels of fat in diet and large quantities of carbohydrates. Some fats, though, such as the Omega-3 fatty acid found in canola and soybean oils play an important protective role.
"Fat was the nutritional demon of the 90s," said Willett. "Without any evidence to support it, the advice was to eat lots of starch."
The focus on carbohydrates has been partly responsible for the epidemic of obesity in the United States, Willett said. Large scale studies such as the Nurses' Health Study, which has followed 121,700 women for 25 years, have established that the trans-fats used in processed foods are the most damaging to the circulatory system, and that women who consumed salad dressings with Omega-3 oils most days of the week, "had reduced risk" of sudden death due to heart disease.
Willett noted that Americans spend $20 billion a year on medication to lower cholesterol. "If all of them followed lifestyle guidelines, the amount would be much lower," Willett said. "We have been on the wrong path."
Bruce Ames, Professor of Biochemistry and Molecular Biology at the University of California, Berkeley, noted that, "to have your biochemistry tuned up, you need about 40 inputs," essential minerals and vitamins that the body needs to function properly.
He cited his work and that of other researchers, who have looked at the impact of vitamin and mineral deficiencies at the cellular level. "Too little iron is a disaster," he said. "It destroys your mitochondria and you get DNA damage." Too little folic acid leads to breaks in the chromosomes that resemble the impact of radiation on the body. Not enough zinc throws off the cellular mechanism for repairing DNA.
"Why not take a vitamin?" Ames asked. "Nutritionists do not like this, for fear that people won't eat their fruits and vegetables. But I say that vitamins are cheap, and they can't hurt."
Ames is studying the impact of two dietary supplements on human longevity, acetyl-L-carnitine and an antioxidant, alpha-lipoic acid. Earlier studies of older rats treated with the supplements had demonstrated improvements in cognitive ability as well as energy levels.
"This makes old rats peppy," Ames said, adding that new research will eventually allow humanity to extend its average life span.
"Life expectancy will get longer every year because a lot of good scientists are working on it," Ames said.
15 October 2003
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