Friday, December 20, 2013
Wednesday, December 18, 2013
'In 1957, a fledgling nutrition scientist at the University of Illinois persuaded a hospital to give him samples of arteries from patients who had died of heart attacks….
It would be more than three decades before those findings were widely accepted — and five decades before the Food and Drug Administration decided that trans fats should be eliminated from the food supply, as it proposed in a rule issued last month.
In the past two years, he has published four papers in peer-reviewed scientific journals, two of them devoted to another major culprit he has singled out as responsible for atherosclerosis, or the hardening of the arteries: an excess of polyunsaturated vegetable oils like soybean, corn and sunflower — exactly the types of fats Americans have been urged to consume for the past several decades.
The problem, he says, is not LDL, the "bad cholesterol" widely considered to be the major cause of heart disease. What matters is whether the cholesterol and fat residing in those LDL particles have been oxidized. (Technically, LDL is not cholesterol, but particles containing cholesterol, along with fatty acids and protein.)
"Cholesterol has nothing to do with heart disease, except if it's oxidized," Dr. Kummerow said. Oxidation is a chemical process that happens widely in the body, contributing to aging and the development of degenerative and chronic diseases. Dr. Kummerow contends that the high temperatures used in commercial frying cause inherently unstable polyunsaturated oils to oxidize, and that these oxidized fatty acids become a destructive part of LDL particles. Even when not oxidized by frying, soybean and corn oils can oxidize inside the body.
If true, the hypothesis might explain why studies have found that half of all heart disease patients have normal or low levels of LDL.
"You can have fine levels of LDL and still be in trouble if a lot of that LDL is oxidized," Dr. Kummerow said.
This leads him to a controversial conclusion: that the saturated fat in butter, cheese and meats does not contribute to the clogging of arteries — and in fact is beneficial in moderate amounts in the context of a healthy diet (lots of fruits, vegetables, whole grains and other fresh, unprocessed foods).
Dr. Robert H. Eckel, an endocrinologist and former president of the American Heart Association, agreed that oxidized LDL was far worse than nonoxidized LDL in terms of creating plaque.
But he disputed Dr. Kummerow's contention that saturated fats are benign and that polyunsaturated vegetable oils promote heart disease. "There are studies that clearly show a substitution of saturated fats with polyunsaturated fats leads to a reduction in cardiovascular disease," said Dr. Eckel, a professor at the University of Colorado…
His early research on trans fats was "resoundingly criticized and dismissed," said Dr. Walter Willett, the chairman of the nutrition department at the Harvard School of Public Health, who credited Dr. Kummerow with prompting his desire to include trans fats in the Nurses' Health Study. A 1993 finding from that study, which showed a direct link between the consumption of foods containing trans fats and heart disease in women, was a turning point in scientific and medical thinking about trans fats.
"He had great difficulty getting funding because the heart disease prevention world strongly resisted the idea that trans fats were the problem," Dr. Willett continued. "In their view, saturated fats were the big culprit in heart disease. Anything else was a distraction from that."'