Presentation on theme: "Saturated Fat and The Dietary Guidelines Richard David Feinman Department of Cell Biology SUNY Downstate Medical Center Brooklyn, NY"— Presentation transcript:
Saturated Fat and The Dietary Guidelines Richard David Feinman Department of Cell Biology SUNY Downstate Medical Center Brooklyn, NY
Look at the problem by analogy with legal system...
...Saturated fat on trial
A criminal indictment: Panel's Conclusions Elevated blood cholesterol level is a major cause of coronary artery disease. It has been established beyond a reasonable doubt that lowering definitely elevated blood cholesterol levels (specifically blood levels of low-density lipoprotein cholesterol ) will reduce the risk of heart attacks due to coronary heart disease...the blood cholesterol level of most Americans is undesirably high, in large part because of our high dietary intake of calories, saturated fat, and cholesterol.... There is no doubt that appropriate changes in our diet will reduce blood cholesterol levels. The Report of the Dietary Guidelines Advisory Committee concurs...
A critical health issue related to dietary fat is the quality of fat in the American diet. The consumption of certain fats, such as saturated fatty acids (SFA) and trans fatty acids, is associated with a poor lipid/lipoprotein profile and increased risk of cardiovascular disease (CVD).
1923 Frye v. United States. Frye appealed a conviction on the grounds that he had passed a lie-detector test, at the time, a simple blood- pressure machine. The Supreme Court upheld the decision since the methodology did not have general acceptance. Opponents of Frye...claimed somewhat improbably, that it would tend to exclude novel, far-sighted testimony by modern-day Galileos. There is no record of this happening once, let alone often. Furthermore, even if a modern-day Galileo did not make into court at first, that fact should not stop him from prevailing in the scientific community. Beyond Frye: Similar viewpoints at American Heart Association, American Diabetes Association, etc.
Rule 702. Testimony by Experts If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case. So, where do the ideas about saturated fat come from?
Keys A: Atherosclerosis: a problem in newer public health. J Mt Sinai Hosp N Y 1953, 20(2): Yerushalmy J, Hilleboe HE: Fat in the diet and mortality from heart disease; a methodologic note. N Y State J Med 1957, 57: le grand paradoxe The six country study.
Keys A: Atherosclerosis: a problem in newer public health. J Mt Sinai Hosp N Y 1953, 20(2): Yerushalmy J, Hilleboe HE: Fat in the diet and mortality from heart disease; a methodologic note. N Y State J Med 1957, 57: Okay, seven countries... the testimony is based upon sufficient facts or data
Professor Aravanis confirmed (Aravanis C, personal communication) that, in the 1960s, 60% of the study participants were fasting during the 40 days of Lent, and strictly followed all fasting periods of the church according to the Greek Orthodox Church dietary doctrines. These mainly prescribe the periodic abstention from meat, fish, dairy products, eggs and cheese, as well as abstention from olive oil consumption on certain Wednesdays and Fridays. However, it is indeed the case that this was not noted in the study, and no attempt was made to differentiate between fasters and non-fasters. In our view this was a remarkable and troublesome omission. the witness has applied the principles and methods reliably to the facts of the case
Although there is no discernible relationship between reported diet intake and serum cholesterol levels in the Framingham Diet Study group, it is incorrect to interpret this finding to mean that diet has no connection with blood cholesterol, Dr. William B. Kannel, director of the Framingham Heart Study has stated. Principle: You cannot be found innocent.
The Skeptics vs. the Preponderance of Evidence
The consumption of certain fats, such as saturated fatty acids (SFA) and trans fatty acids, is associated with a poor lipid/lipoprotein profile and increased risk of cardiovascular disease (CVD). the danger of unfair prejudice
Science and the Law: Daubert v. Merrell Dow, Inc. Jason Daubert and Eric Schuller were born with serious birth defects. They claimed that Bendectin, an anti-nausea drug taken by their mothers during pregnancy caused the birth defects. The District Court ruled that Dauberts evidence was not admissible under the Frye general acceptance idea. Ultimately the case was heard by the Supreme Court. Justice Blackmun delivered the opinion that Frye was superseded by the Federal Rules of Evidence. The court cited works of philosophers of science, particularly Karl Popper: "The criterion of the scientific status of a theory is its falsifiability, or refutability, or testability." Daubert can be succinctly described as a new two-pronged test: scientific evidence had to be reliable and relevant. Reliable meant that conclusions were derived from: hypothesis testing peer review and publication known or potential rates of error and standards controlling the techniques operation. general acceptance of the methodology in the relevant discipline Question: is the case against saturated fat falsifiable? Lets go to the NEL...
Comparison of monounsaturated fat with carbohydrates as a replacement for saturated fat in subjects with a high metabolic risk profile: studies in the fasting and postprandial states Lars Berglund, Michael Lefevre, Henry N Ginsberg, Penny M Kris-Etherton, Patricia J Elmer, Paul W Stewart, Abby Ershow, Thomas A Pearson, Barbara H Dennis, Paul S Roheim, Rajasekhar Ramakrishnan, Roberta Reed, Kent Stewart, and Katherine M Phillips for the DELTA Investigators Results: Relative to the AAD, LDL cholesterol was lower with both the CHO (-7.0%) and MUFA (-6.3%) diets... Conclusions: In the study population, who were at increased risk of coronary artery disease, MUFA provided a greater reduction in risk as a replacement for saturated fat than did carbohydrate. Am J Clin Nutr 2007;86:1611–20. reliable?
PUFA for SFA reduces risk CHO for SFA reduces risk PUFA: risk CHO: risk DGAC: replacing SFA with unsaturated fats is more effective in decreasing CVD risk than is reducing total fat intake overall. known or potential rates of error and standards controlling the techniques operation.
Exculpatory Evidence: Brady v. Maryland. Brady and an accomplice were convicted of first degree murder and were sentenced to death. The accomplice confessed to having actually committed the murder and the Supreme Court ruled that the punishment should be reduced because the prosecution had withheld the confession.... Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased A California State court ruled that a prosecutor could not avoid Brady responsibilities by looking the other way.
Question 1. What is the Effect of Saturated Fat Intake on Increased Risk of Cardiovascular Disease or Type 2 Diabetes...? Conclusion Strong evidence indicates that intake of dietary SFA is positively associated with intermediate markers and end point health outcomes for two distinct metabolic pathways: 1) increased serum total and LDL cholesterol and increased risk of CVD and 2) increased markers of insulin resistance and increased risk of T2D.
Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study Irene M Stratton, Amanda I Adler, H Andrew W Neil, David R Matthews, Susan E Manley, Carole A Cull, David Hadden, Robert C Turner, Rury R Holman on behalf of the UK Prospective Diabetes Study Group BMJ 2000;321;
Jakobsen MU, et al: Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. Am J Clin Nutr 2009, 89(5):
Conversation with Jessica A. Feinman, MD: JAF: Remember, Dad, Im a psychiatrist. We used to treat patients by sticking an ice-pick in their brain. RDF: Isnt recommending reducing saturated fat instead of carbohydrate, as bad a scandal as any in the history of medicine. Carbohydrate restriction provides immediate improvement in blood glucose and other symptoms of diabetes. Carbohydrate restriction provides long term reduction in risk of CVD. The data on saturated fat are conjectural. You may get a benefit by replacing saturated fat. Or things may get worse. Not stay the same. May get worse. Choose between immediate benefit and conjecture on long term outcome. Question 1. What is the Effect of Saturated Fat Intake on Increased Risk of Cardiovascular Disease or Type 2 Diabetes...? Conclusion Strong evidence indicates that intake of dietary SFA is positively associated with intermediate markers and end point health outcomes for two distinct metabolic pathways: 1) increased serum total and LDL cholesterol and increased risk of CVD and 2) increased markers of insulin resistance and increased risk of T2D.