Is the American Heart Association wrong about their recommendation to avoid foods high in cholesterol and to replace saturated fats, like those found in animal foods, with polyunsaturated fats, like those found in vegetable oils? A growing number of experts think so, including a 98-year-old researcher from the University of Illinois who argues that the main cause of heart disease is not dietary cholesterol but rather oxidized cholesterol and fats—especially from too many polyunsaturated vegetable oils and fried foods.
Dr. Fred Kummerow, an emeritus professor of comparative biosciences, recently published a paper in the American Journal of Cardiovascular Disease reviewing his life’s work of 60 years on the dietary factors—especially oxidized cholesterol–that contribute to heart disease. In Dr. Kummerow’s view and the view of an increasing number of experts, the primary cause of heart disease is oxidized cholesterol and fats. When fats degrade, free radicals “steal” electrons and a free radical chain reaction mechanism ensues, leading to cell damage.
The 3 main causes of heart disease linked to oxidized cholesterol:
According to Kummerow, there are three diet and lifestyle factors that underlie the current epidemic of heart disease, each related to oxidized cholesterol and fats. They are:
- the consumption of commercially fried foods such as fried chicken and french fries
- the consumption of excess polyunsaturated fatty acids from vegetable oils
- cigarette smoking
Kummerow cites research from his own lab as well as other researchers’ findings on lipid metabolism and heart disease which reveal the underlying mechanisms linking oxidized cholesterol and fats (and trans fats) to heart disease. The three factors above, he asserts, along with the consumption of trans fatty acids from partially hydrogenated vegetable oil, are the dietary and lifestyle factors that most lead to atherosclerosis. Atherosclerosis is the process by which the arteries become hardened and build up with plaques leading to heart attacks and sudden death.
How oxidized cholesterol and fat leads to atherosclerosis
Over the years, Kummerow and his collaborators found two distinct ways in which oxidized cholesterol and fats lead to atherosclerosis: they enhance calcification of the arteries and promote the synthesis of a compound that increases blood clotting. “Oxidized lipids contribute to heart disease both by increasing deposition of calcium on the arterial wall, a major hallmark of atherosclerosis, and by interrupting blood flow, a major contributor to heart attack and sudden death,” writes Kummerow in his review.
One of Kummerow’s main contributions to the growing body of research on oxidized cholesterol has to do with a compound called sphingomyelin. Kummerow found that people with heart disease have higher levels sphingomyelin in the walls of their arteries, especially at the branch points of the arteries that supply blood to the heart, which is where the most blockages occur. They also have significantly more oxidized cholesterol in their blood and tissues than people without heart disease. The researchers found that the more oxidized cholesterol in the blood, the more sphingomyelin in the walls of the arteries. And the more sphingomyelin, the more arteries become calcified.
While other studies have also demonstrated a link between higher sphingomyelin levels and the calcification of coronary arteries, Kummerow’s team discovered the mechanism by which this occurred. They noted that lipids like sphingomyelin develop a negative charge in the presence of certain salts, explaining the attraction of positively charged calcium to the arterial wall when high amounts of sphingomyelin are present.
How to avoid oxidized cholesterol and heart disease
According to the U.S. Department of Agriculture, we have switched from the consumption of saturated fats to polyunsaturated fats, which are now in almost everything that is consumed. Kummerow states in his conclusion, “Vegetables oils, partially hydrogenated fats, and fried foods are responsible for the persistently high rate of heart disease. The most effective way to prevent coronary heart disease and sudden death according to these conclusions is to eat fewer commercially fried foods, fewer polyunsaturated fats and to avoid partially hydrogenated fats. Conversely, we should eat more vegetables and fruit as a source of antioxidants.”
Learn more about the importance of oxidized cholesterol here:
- Cholesterol: Getting to the Heart of the Matter
- 4 Big Cholesterol Myths
- Natural Cholesterol Control: Achieve Healthy Cholesterol Levels without Drugs
This article was originally published in 2013 and has been updated.