Additional research on saturated fats

Following is additional research with citations on some common assumptions about saturated fats.

Sound Consumer | October 2010

by Cherie Calbom, M.S.

(October 2010)

Assumption #1. “It has been a settled question for years that unsaturated fats in the diet reduce the incidence of cardiovascular disease, while a diet high in saturated fats increases the incidence of cardiovascular disease.”

This question is anything but settled. The fact that we continue on the same old path with loss of so many lives is completely unsettling. Many studies now are pointing to a flawed lipid hypothesis.

An article appeared April 27, 2010, in Scientific American suggesting it may be refined carbs rather than saturated fat that threatens the heart. Melinda Moyer writes, “But while Americans have dutifully reduced the percentage of daily calories from saturated fat since 1970, the obesity rate during that time has more than doubled, diabetes has tripled, and heart disease is still the country’s biggest killer. Now a spate of new research, including a meta-analysis of nearly two dozen studies, suggests a reason why: investigators may have picked the wrong culprit. Processed carbohydrates, which many Americans eat today in place of fat, may increase the risk of obesity, diabetes and heart disease more than fat does — a finding that has serious implications for new dietary guidelines expected this year. [1]

“In March the American Journal of Clinical Nutrition published a meta-analysis — which combines data from several studies — that compared the reported daily food intake of nearly 350,000 people against their risk of developing cardiovascular disease over a period of five to 23 years. The analysis, overseen by Ronald M. Krauss, director of atherosclerosis research at the Children’s Hospital Oakland Research Institute, found no association between the amount of saturated fat consumed and the risk of heart disease.” [2]

“The finding joins other conclusions of the past few years that run counter to the conventional wisdom that saturated fat is bad for the heart because it increases total cholesterol levels. That idea is ‘based in large measure on extrapolations, which are not supported by the data,’ Krauss says. [1]

“One problem with the old logic is that 'total cholesterol is not a great predictor of risk,' according to Meir Stampfer, professor of nutrition and epidemiology at the Harvard School of Public Health. Stampfer co-authored a study in 2008 in the 'New England Journal of Medicine' that monitored 322 obese people for two years as they followed one of three diets: 1) a low-fat, calorie-restricted diet based on American Heart Association guidelines, 2) a Mediterranean, restricted-calorie diet rich in vegetables and low in red meat, and 3) a low-carbohydrate, nonrestricted diet. Results showed that although people on the low-carb diet ate the most saturated fat, they ended up with the healthiest ratio of HDL to LDL cholesterol and lost twice as much weight as their low-fat-eating counterparts.” [1]

“Nobody is advocating that people start gorging themselves on saturated fats, and some monounsaturated and polyunsaturated fats, such as those in fish and olive oil, can help protect against heart disease. Some high-fiber carbohydrates also undoubtedly are good for the body.” [1]

David Ludwig, director of the obesity program at Children’s Hospital Boston, explains, “If you reduce saturated fat and replace it with high glycemic-index carbohydrates, you may not only not get benefits — you might actually produce harm.” He says the next time you eat a piece of buttered toast, consider that “butter is actually the more healthful component.” [1]

Assumption #2. “The higher the ratio of unsaturated to saturated fats in the diet the more anti-atherogenic and cardio-protective the diet is.”

Studies show that unsaturated fats show up in large quantities in the plaque of blood vessels. As mentioned in my article, a study conducted at the Wynn Institute for Metabolic Research in London (Lancet, 1994) examined the composition of human aortic plaques.

It found in the people studied that the artery-clogging fats in those who died from heart disease were composed of 26 percent saturated fat and 74 percent polyunsaturated fatty acids (PUFAs). They determined no association with saturated fats but rather implicated PUFAs, such as those found in polyunsaturated vegetable oils, as the primary contributors to aortic plaque formation and suggested that people avoid these oils completely. [3]

In January, 2008, the New York Times reported: "For decades, the theory that lowering cholesterol is always beneficial has been a core principle of cardiology. It has been accepted by doctors and used by drug makers to win quick approval for new medicines to reduce cholesterol. But now some prominent cardiologists say the results of two recent clinical trials have raised serious questions about that theory.

“The idea that you're just going to lower LDL and people are going to get better, that's too simplistic, much too simplistic,'’ said Dr. Eric J. Topol, a cardiologist and director of the Scripps Translational Science Institute in La Jolla, Calif. “Because the link between excessive LDL cholesterol and cardiovascular disease has been so widely accepted, the FDA generally has not required drug companies to prove that cholesterol medicines actually reduce heart attacks before approval...." [4]

Dr. George Mann, M.D. Professor of Medicine & Biochemistry, Vanderbilt University, stated, "A generation of research on the diet-heart question has ended in disarray. The official line since 1950 for management of the epidemic of coronary heart disease has been a dietary treatment. Foundations, scientists and the media, both lay and scientific, have promoted low fat, low cholesterol, polyunsaturated diets, and yet the epidemic continues unabated, cholesteremia in the population is unchanged, and clinicians are unconvinced of efficacy. Saturated fat and cholesterol in the diet are NOT the cause of coronary heart disease. The 'diet-heart' idea is the greatest scientific deception of this century, perhaps any century. Never in the history of science have so many costly experiments failed so consistently. Fearing to lose their soft money funding, the academicians who should speak up and stop this wasteful anti-science are strangely quiet. Their silence has delayed a solution for coronary heart disease by a generation." [5]

In 1994, Dr. Harlan Krumholz of the Department of Cardiovascular Medicine at Yale University reported that old people with low cholesterol died twice as often from a heart attack as did old people with high cholesterol. The researchers stated, “Elevated total serum cholesterol level, low HDL-C, and high total serum cholesterol to HDL-C ratio were not associated with a significantly higher rate of all-cause mortality, coronary heart disease mortality, or hospitalization for myocardial infarction or unstable angina after adjustment for cardiovascular risk factors.” [6]

If, as we have been told, heart disease results from the consumption of saturated fats, one would expect to find a corresponding increase in animal fat in the American diet. Actually, the reverse is true.

During the 60-year period from 1910 to 1970, the proportion of traditional animal fat in the American diet declined from 83 percent to 62 percent, and butter consumption plummeted from 18 pounds per person per year to four.

During the past 80 years, dietary cholesterol intake has increased only 1 percent. During the same period the percentage of dietary vegetable oils in the form of margarine, shortening and refined unsaturated oils increased about 400 percent, while the consumption of sugar and processed foods increased about 60 percent.

The Framingham Heart Study is often cited as proof of the lipid hypothesis. This study began in 1948 and involved some 6,000 people from the town of Framingham, Massachusetts. Two groups were compared at five-year intervals—those who consumed little cholesterol and saturated fat and those who consumed large amounts. After 40 years, the director of this study, Dr. William Castelli, published in a major, peer-reviewed journal the following statement: “In Framingham, the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the persons' serum cholesterol.” [7]

The Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT), which cost 150 million dollars, is the study most often cited by the experts to justify low-fat diets. Actually, dietary cholesterol and saturated fat were not tested in this study, as all subjects were given a low-cholesterol, low-saturated-fat diet. Instead, the study tested the effects of a cholesterol-lowering drug. Their statistical analysis of the results implied a 24 percent reduction in the rate of coronary heart disease in the group taking the drug compared with the placebo group. However, non-heart disease deaths in the drug group increased — deaths from cancer, stroke, violence and suicide. [8]

Assumption #3. “Oxidized saturated fats accumulate in the plaque of blood vessels and unsaturated fats do not.”

It is widely accepted that oxidized cholesterol is implicated in heart disease, rather than general LDL. Most often we just hear about general cholesterol without distinguishing that is the oxidized cholesterol and fats that are damaging.

Cholesterol is oxidized when it is exposed to sunlight, oxygen, or heat. Cholesterol in the body also can be oxidized by free radical reactions when we consume rancid oils, toxins, or pollutants. Rancid oils are produced when polyunsaturated oils (PUFAs), in particular, oxidize.

I noted PUFAs in particular because they have more than one double bond, which can be broken rather easily when exposed to heat, sunlight and oxygen, and thus have the greatest propensity to oxidize. Oxidation can happen in the processing of these oils. These oils are deodorized, which means that we don’t know (can’t smell) when they are rancid. Free radicals are produced in the process and they are one of the primary causes of oxidized cholesterol. This process is accelerated with heat.

There are studies that show heart disease can be caused by unsaturated oils in the diet. Polyunsaturated fatty acids have been found in high quantity in artery plaque. (See the Wynn Institute Study referred to below.)

A report published in Food Service Research International (June, 2006) says, “considerable evidence has accumulated over the past two decades that heated cooking oils, especially polyunsaturated oils, may pose several types of health risks to consumers.”[9] It lists cardiovascular disease as one of those risks attributed to lipid oxidation. It points out that heat degrades polyunsaturated fatty acids to toxic compounds.

Assumption #4. “The American medical community emphasizes the 'Mediterranean Diet' — olive oil-based and high in unsaturated fats — as a healthy diet for prevention of cardiovascular disease.”

Yes, the Mediterranean diet includes olive oil, but just as or more important, it is rich in fresh fruit, fresh vegetables, fish, beans, seeds, nuts, butter, and yogurt in modest amounts. It’s a great diet. Fried foods, processed foods, and polyunsaturated oils are not common. But remember, oxidized oils are the culprit in contributing to heart disease.

Olive oil is healthy oil and I highly recommend it. It tends to be more shelf stable, like coconut and palm oil, than polyunsaturated oils. Cold-pressed, unrefined virgin olive oil, like the Mediterranean people eat, is ideal for raw foods, salad dressings, and light sautéing — but it’s not good for medium to high-heat cooking because it has a lower smoke point (305 to 320° F) and will oxidize more easily with heat. High quality olive oil stands out also as an antioxidant/free radical fighter. In my article, I named fats and oils that are good choices.

Saturated fats don’t have double bonds that can be broken easily and they don’t tend to oxidize (turn rancid) as easily as the polyunsaturated fats. Using them in small amounts has not been shown to be harmful. I note in the article what has been shown to be harmful.

We need an open mind

If we fail to allow dialogue about this issue but consider it “settled,” we may never get to the truth about what causes heart disease and why we have not significantly reduced its incidence with decades of promoting low-fat and unsaturated fat diets. We must be aware that politics and money have suppressed truth and swayed public opinion. Please consider:

  • Saturated fat was a mainstay of the human diet for thousands of years; atherosclerosis was not a problem until the twentieth century when man-made oils and other foods were introduced.
  • Dr. Mary Enig, Ph.D. (a noted expert on fats and oils) says, “The theory — called the lipid hypothesis — that there is a direct relationship between the amount of saturated fat and cholesterol in the diet and the incidence of coronary heart disease was proposed by a researcher named Ancel Keys in the late 1950’s. Numerous subsequent studies have questioned his data and conclusions. Nevertheless, Keys’ articles received far more publicity than those presenting alternate views. The vegetable oil and food processing industries, the main beneficiaries of any research that found fault with competing traditional foods, began promoting and funding further research designed to support the lipid hypothesis.”[10]

    If we look back at the history of fats and oils, the increase in heart disease parallels the increased use of vegetable oils over traditional fats. Dr. Enig explains that before 1920 coronary heart disease was rare in America; so rare that when a young internist named Paul Dudley White introduced the German electrocardiograph to his colleagues at Harvard University, they advised him to concentrate on a more profitable branch of medicine. The new machine revealed the presence of arterial blockages, thus permitting early diagnosis of coronary heart disease. But in those days clogged arteries were a medical rarity, and White had to search for patients who could benefit from his new technology. During the next 40 years, however, the incidence of coronary heart disease rose dramatically, so much so that by the mid-1950s heart disease was the leading cause of death among Americans. Today heart disease causes at about 34 percent of all US deaths.[11]
  • George Mann's independent studies of the Masai in Africa convinced him that the lipid hypothesis was "the public health diversion of this century.”[12]
  • When people ingest foods prepared with processed vegetable oils – margarine, French fries, fried food, non-fat dried milk, powdered or liquid coffee creamer, many salad dressings, crackers, cookies, chips, and a plethora of other processed and convenience foods, they eat a high quantity of oxidized (rancid) oil. Processed vegetable oils have an unstable chemical structure. They are free radicals in waiting. Free radicals cause cholesterol to oxidize. They also damage cells, they trigger inflammation (a leading cause of heart disease), and they can damage blood vessels. This is the reason these unsaturated fats are so dangerous. This should be the warning given to consumers.
  • I do not recommend eating large quantities of animal fat. There are reasons not to eat very much animal fat: Toxins typically are stored in fat cells because it’s one of the safest places for a body to store them. Free radicals are produced when we are exposed to toxins (or pollutants) and we know that free radicals are implicated in creating oxidized cholesterol, the harmful substances found in artery plaque. With the exception of the fine organic pastured butter (and other organic animal products) that PCC sells, it is fairly safe to say that most other animal fat would contain a lot of toxins based on the poor quality diet that factory-farm animals are fed. It is for this reason that I don’t recommend animal fat unless a person is eating butter from organically raised, pastured and grass-fed cows. Even then, these fats should be consumed in small quantities.
  1. Carbs against Cardio: More Evidence that Refined Carbohydrates, not Fats, Threaten the Heart. Scientific American, May 2010.
  2. Patty W. Siri-Tarino, Qi Sun, Frank B. Hu, and Ronald M. Krauss. "Meta-analysis of propective cohort studies evaluating the association of saturated fat with cardiovascular disease." The American Journal of Clinical Nutrition; 91:535-546. March, 2010.
  3. Felton, C V: Crook, D : Davies, M J : Oliver, M F Dietary polyunsaturated fatty acids and composition of human aortic plaques. Lancet. 1994 Oct 29; 344(8931): 1195-6
  4. Alex Berenson, New Questions on Treating Cholesterol, New York Times, Business Section, January 17, 2008
  5. George V. Mann, M.D. Professor of Medicine & Biochemistry, Vanderbilt University. 1991; and author of "Diet-heart: End of an era". New England Journal of Medicine; 297, 644-650. 1977; and "Coronary heart disease- Doing the wrong things". Nutrition Today; July/August, p. 12-14. 1985.
  6. Harlan M. Krumholz, MD; Teresa E. Seeman, PhD; Susan S. Merrill, PhD; Carlos F. Mendes de Leon, PhD; Viola Vaccarino, MD; David I. Silverman, MD; Reiko Tsukahara, MD; Adrian M. Ostfeld, MD; Lisa F. Berkman, PhD, Lack of Association Between Cholesterol and Coronary Heart Disease Mortality and Morbidity and All-Cause Mortality in Persons Older Than 70 Years JAMA. 1994;272(17):1335-1340
  7. Castelli,William, Arch Int Med, Jul 1992, 152:7:1371-1372
  8. The Lipid Research Clinics Coronary Primary Prevention Trial Results. Reduction in Incidence of Coronary Heart Disease," JAMA, 1984, 251:359
  9. M. Grootveld, et al. The Effects of Oxidized Heated Oils Foodservice Research International 30 JUN 2006Volume 13, Issue 1, pages 41–55, October 2001
  10. Mary Enig, Know Your Fats (Silver Spring, MD: Bethseda Press; 2000
  11. Mary Enig, Know Your Fats (Silver Spring, MD: Bethseda Press; 2000
  12. Mann, G V, et al, "Atherosclerosis in the Maasai," Am J Epidemiology, 1972, 95:26-37

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