March 23, 2014
I’ve been asked by viewers to comment on a couple recently published journal articles which have received undeserved attention from the media. These articles are a major meta-analysis examining associations between dietary and circulating fatty acids with coronary disease (Chowdhury, 2014) and yet another editorial proclaiming that we’ve been wrong all along about saturated fat (DiNicolantonio, 2014). If you’ve watched enough of my videos you should know by now what tactics are commonly utilized to keep us all ignorant and confused about cholesterol and heart disease. The present blog post will show you that these two articles are just more of the same. Because I’m so busy nowadays, I’m giving these two a very cursory treatment here just to give you a sense of what’s going on in them. Bear in mind that the first article is the product of a professional collaboration of many researchers who were paid for their efforts. I am but one person taking advantage of a brief chunk of free time. I’ll post corrections in my Errata if I see that that becomes necessary.
Let’s start with the Chowdhury meta-analysis. Dr. Chowdhury has admitted to a half dozen errors in his paper that he says do not affect his conclusions. This was partly in response to the comments of Walter Willett, Frank Sacks, and Meir Stampfer, who called his conclusions about MUFAs and PUFAs “seriously misleading.”
This paper is quite like the 2010 meta-analysis of Siri-Tarino, et al (Siri-Tarino, 2010), which I have previously discussed. Only a weak subset of the literature on heart disease is examined, excluding the most convincing evidence for Diet-Heart, yet an incautious and unsupportable conclusion is offered in its abstract, in this case proclaiming that “Current evidence does not clearly support cardiovascular guidelines that encourage … low consumption of total saturated fats.” This statement suggests to the naïve reader that the most important evidence in Diet-Heart has been considered and rejected in this paper, but that impression would be false. A few examples of what I consider strong evidence are presented together at the end of this video. These are mostly ignored by Chowdhury.
To understand why I consider Chowdhury and company’s evidence to be weak, have a look at some of the studies they thought were good enough to be included in their analysis (I’ve added the boldface, references found in the online supplement 1).
1.) Referenced as EUROASPIRE. Relative risk: 1.00 for dietary SFA. (Erkkilä, 2003).
“The analyses were adjusted for sex, age, diagnostic category (CABG or PTCA compared with AMI or AMIS), education (< 12 compared with ≥ 12 y), serum cholesterol concentration, serum triacylglycerol concentration, body mass index, and diabetes, and models that included nutrient or food intakes were also adjusted for energy intake.”
"Virtually all the patients were taking cardiovascular drugs, and this could have confounded the observed associations." (quoting the authors of the paper)
2.) Referenced as IIHD. Relative risk: 0.90 for dietary SFA. (Goldbourt, 1993).
“A curvilinear increase in fatal CHD risk with increasing total cholesterol was observed.”
3.) Referenced as Caerphilly. Relative risk: 0.92 for dietary SFA. (Fehily, 1993).
“An alternative explanation which has been suggested (Rose, 1985) is that, in populations where the majority have a high fat intake, factors other than fat become important in determining why some individuals develop IHD and others do not.”
4.) Referenced as LURIC. Relative risk: 0.81 for circulating palmitic acid. (Pilz, 2007).
“In detail, we adjusted for age, sex, body mass index, systolic and diastolic blood pressure, hypertension, HOMA-IR, type 2 diabetes, triglycerides, low-density lipoprotein and high-density lipoprotein cholesterol, homocysteine, creatinine, smoking status (current and active smoker: yes/no), CAD, left bundle branch block, C-reactive protein, use of beta-blockers, ACE-inhibitors and statins, NT-pro-BNP, noradrenaline, and LV function.”
“Our study shows that elevated plasma FFAs are an independent risk factor for future SCD in patients referred to coronary angiography.” (SCD: sudden cardiac death).
Note: “Current ketogenic diets are all characterized by elevations of free fatty acids” (Veech, 2004).
5.) Referenced as JELIS. Relative risk: 0.85 for circulating palmitic acid. (Yokoyama, 2007).
“Patients were randomly assigned to receive EPA with statin (EPA group) or statin alone (controls).”
In short, based on the few that I reviewed, many of the studies they selected have similar defects to those used in the Siri-Tarino paper, and in fact, it seems from quick inspection that they used some of the very same studies. The above are given equal weight to another study, one which observed a cohort in which real contrasts in the dietary habits might give us a better chance of learning something interesting.
Referenced as Oxford Vegetarian. Relative risk: 2.77 for dietary SFA (Mann, 1997).
“A gradient of risk is apparent with increasing intake of total animal fat, saturated fat, and dietary cholesterol as well as some of the major food sources of these nutrients.”
Given the considerable challenges inherent in Diet-Heart studies of free-living people in homogeneous populations, we should approach such a large meta-analysis with caution. Such an analysis can only be as good as the studies upon which it is based (Garg, 2008), so it is necessary to first assess them for their quality and winnow down the selection accordingly. It appears Dr. Chowdhury and colleagues were too permissive in their standards of inclusion to advance our understanding of Diet-Heart very much with this article. Additionally, it appears that one of the authors of this study, Dr. Dariush Mozaffarian, is misinformed about the effects of saturated fat upon lipoproteins. He told the Boston Globe that, “Saturated fat in the diet makes LDL particles bigger, but it doesn’t increase the number of LDL particles, which we now think is responsible for the increased heart risk.” Unfortunately, he is wrong about this (Zock, 1994). Please see my videos about foods that increase our production of atherogenic particles for further information. I wonder if his mistaken belief impaired his critical thinking on this issue.
Now let’s shift our attention to that opinion piece by Dr. DiNicolantonio. He begins by repeating that familiar old libel against Ancel Keys based on the highly flawed work of Yerushalmi and Hilleboe (1957). He says, “(Keys) excluded data from 16 countries that did not fit his hypothesis. Indeed, data were available at the time from 22 countries.” This assertion has been debunked by me in several videos, including this one and this one, and Keys’ arguments were later affirmed using the same data set in papers by Puffer and Verhoestraete (1958) and Joliffe and Archer (1959). The most innocent interpretation of this passage must be that Dr. DiNicolantonio has not bothered to research this matter properly. If he in fact knows the truth of this matter, that would be very troubling. The rest of his article is just another repackaging of the usual junk thought of the low-carb fringe. He asserts that “the belief that … saturated fats increase total cholesterol” is a “flawed theory” without any reference, despite the fact that hundreds of controlled trials have shown that they do (Clarke, 1997). I could go on but I don’t think that’s necessary. Just search my site and watch my videos and you’ll see how misguided he is.
Chowdhury, Rajiv, et al. "Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis."Annals of Internal Medicine 160.6 (2014): 398-406.
Clarke, Robert, et al. "Dietary lipids and blood cholesterol: quantitative meta-analysis of metabolic ward studies." Bmj 314.7074 (1997): 112.
DiNicolantonio, James J. "The cardiometabolic consequences of replacing saturated fats with carbohydrates or Ω-6 polyunsaturated fats: Do the dietary guidelines have it wrong?." Open Heart 1.1 (2014): e000032.
Erkkilä, Arja T., et al. "n− 3 fatty acids and 5-y risks of death and cardiovascular disease events in patients with coronary artery disease." The American journal of clinical nutrition 78.1 (2003): 65-71.
Fehily, A. M., et al. "Diet and incident ischaemic heart disease: the Caerphilly Study." British Journal of Nutrition 69.02 (1993): 303-314.
Garg, Amit X., Dan Hackam, and Marcello Tonelli. "Systematic review and meta-analysis: when one study is just not enough." Clinical Journal of the American Society of Nephrology 3.1 (2008): 253-260.
Goldbourt, Uri, Shlomit Yaari, and Jack H. Medalie. "Factors predictive of long-term coronary heart disease mortality among 10,059 male Israeli civil servants and municipal employees." Cardiology 82.2-3 (1993): 100-121.
Jolliffe, Norman, and Morton Archer. "Statistical associations between international coronary heart disease death rates and certain environmental factors." Journal of chronic diseases 9.6 (1959): 636-652.
Mann, Jim I., et al. "Dietary determinants of ischaemic heart disease in health conscious individuals." Heart 78.5 (1997): 450-455.
Pilz, Stefan, et al. "Elevated plasma free fatty acids predict sudden cardiac death: a 6.85-year follow-up of 3315 patients after coronary angiography."European heart journal 28.22 (2007): 2763-2769.
Puffer, Ruth R., and Louis J. Verhoestraete. "Mortality from cardiovascular diseases in various countries, with special reference to atherosclerotic heart disease: A preliminary analysis*." Bulletin of the World Health Organization19.2 (1958): 315.
Siri-Tarino, Patty W., et al. "Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease." The American journal of clinical nutrition 91.3 (2010): 535-546.
Veech, Richard L. "The therapeutic implications of ketone bodies: the effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism." Prostaglandins, leukotrienes and essential fatty acids 70.3 (2004): 309-319.)
Yerushalmy, Jacob, and Herman E. Hilleboe. "Fat in the diet and mortality from heart disease; a methodologic note." New York State journal of medicine 57.14 (1957): 2343-2354.
Yokoyama, Mitsuhiro, et al. "Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomised open-label, blinded endpoint analysis." The Lancet 369.9567 (2007): 1090-1098.
Zock, Peter L., J. H. De Vries, and Martijn B. Katan. "Impact of myristic acid versus palmitic acid on serum lipid and lipoprotein levels in healthy women and men." Arteriosclerosis, Thrombosis, and Vascular Biology 14.4 (1994): 567-575.