Diet-Heart: A Problematic Revisit

In 2010, Jeremiah Stamler published the editorial 4 Perhaps the cholesterol skeptics attain non portion Stamler’s involvement of saving lives, explaining why they induce got chosen to refrain from informing their audience of Stamler’s findings. 

Another shortcoming of the Siri-Tarino et al. meta-analysis newspaper was the lack of acknowledgement inwards the assessments in addition to conclusions that major cross-population studies amongst a prospective (future looking) design, such every bit the Seven Countries Study found that saturated fatty was associated amongst a significantly increased remove a opportunity of fatal coronary pump illness (Fig. 1).5 Consistent amongst the tendency of the findings from the Seven Countries Studies, the nomadic Kirghiz plainsmen who subsist on a diet of enormous amounts of organic grass-fed milk in addition to meat sense severe vascular illness at a rattling immature age [reviewed previously].

Figure 1. Saturated fatty every bit % of calories in addition to fatal coronary pump illness inwards sixteen cohorts from the Seven Countries Study

In this serial of posts I volition review the diet-heart hypothesis in addition to the arguments against the hypothesis raised past times known cholesterol skeptics. Note that inwards this review the diet-heart hypothesis refers to the hypothesis that dietary change, such every bit the exchange of private dietary fats for refined saccharify influences serum (blood) lipids (including serum full in addition to LDL cholesterol), in addition to hence at the rattling to the lowest degree indirectly influences the remove a opportunity of developing coronary pump disease.

Stephan Guyenet, the writer of the Whole Health Source weblog has produced around rattling informative posts dispelling Gary Taubes’s misleading claims regarding refined saccharify metabolism, insulin in addition to obesity.6 Unfortunately, similar Taubes rather than embracing the preponderance of bear witness that has established the diet-heart hypothesis, Guyenet has chosen to confuse the discipline inwards a serial of weblog posts. I induce got previously commented on Guyenet’s weblog regarding i such concerning post inwards May 2011 where I raised my concerns regarding Guyenet’s arguments against the bear witness that saturated fatty raises serum cholesterol, in addition to increases the remove a opportunity of coronary pump disease.7  

One of my top dog concerns I presented inwards my comments on Guyenet’s weblog was his lack of acknowledgement that saturated fatty was associated amongst an increased remove a opportunity of fatal coronary pump illness inwards the Health Professional’s Follow-up Study in addition to inwards Stamler’s meta-analysis. Guyenet was less than appreciative of these comments, stating:

I honour it disturbing that y'all operate along to advert the Health Professionals follow-up written report to back upward your position despite the fact that at that spot was no statistically meaning association betwixt SFA intake in addition to whatsoever mensurate of CHD subsequently maximum adjustment. If at that spot were genuinely a human relationship betwixt the ii factors, y'all wouldn't induce got to advert non-significant findings to back upward your position.

In the newspaper from the Health Professional’s Follow-up Study cited past times Guyenet, for men inwards the ambit verses the lowest 5th of saturated fatty intake the relative remove a opportunity for fatal coronary pump illness was 1.72 (95% confidence interval 1.01 to 2.90) subsequently maximum adjustment.8 In other words this written report found that saturated fatty intake was associated amongst a statistically meaning 72% increased remove a opportunity of fatal coronary pump illness for high compared to depression intake. Guyenet avoided straight responding to my comments regarding the finding inwards Stamler’s meta-analysis for fatal coronary pump disease, in addition to only referred dorsum to the Siri-Tarino et al. meta-analysis which failed to address this fatal halt point.

In this item post that I commented on, Guyenet made several misleading statements inwards reference to the findings from the Siri-Tarino et al. meta-analysis: 

Nearly every high-quality (prospective) observational written report always conducted found that saturated fatty intake is non associated amongst pump assault risk. So if saturated fatty increases blood cholesterol, in addition to higher blood cholesterol is associated amongst an increased remove a opportunity of having a pump attack, in addition to so why don't people who swallow to a greater extent than saturated fatty induce got to a greater extent than pump attacks?

Apart from the failure to admit that Stamler demonstrated that the cohort studies included inwards this meta-analysis found that saturated fatty intake was genuinely associated amongst an increased remove a opportunity of fatal coronary pump disease, at that spot are several other points inwards this declaration that are problematic that volition live addressed separately.

The Problem of Overadjustment 

Guyenet’s proposition that the Siri-Tarino et al. meta-analysis should induce got found a positive association betwixt saturated fatty in addition to coronary pump illness if saturated fatty raises serum cholesterol in addition to serum cholesterol increases the remove a opportunity of coronary pump illness is misleading. One of the close serious flaws inwards this meta-analysis was the inclusion of overadjustments for serum lipids in addition to dietary lipids, which would induce got obscured this diet-cholesterol-heart human relationship that Guyenet referred to. Stamler addressed this flaw inwards the editorial:5 Another strength of the Seven Countries Study is that dietary intake was assessed betwixt groups of individuals which has been shown to resultant inwards less measurement mistake than assessing dietary intakes betwixt individuals every bit was done inwards the cohort studies included inwards the Siri-Tarino et al. meta-analysis.11 Another employment that could induce got potentially obscured the findings inwards these studies, peculiarly those that lasted into the statin era is that participants amongst higher serum cholesterol every bit a resultant of a high saturated fatty intake maybe to a greater extent than probable to induce got received aggressive medical intervention inwards companionship to preclude cardiovascular disease. It should live emphasized hither that Stamler found inwards a meta-analysis that saturated fatty was associated amongst a 32% increased remove a opportunity of fatal coronary pump illness despite such problems.reviewed previously].24

Siri-Tarino et al. excluded cohort studies of type II diabetics patients from the meta-analysis which should live addressed. Two such studies found a rattling strong association betwixt saturated fatty in addition to cardiovascular disease, including the Nurses’ Health Study which too found a meaning association for dietary cholesterol in addition to the Keys score.Part I in addition to Part II of a review addressing blood pressure, blood cholesterol, diet in addition to the remove a opportunity of stroke, which too addresses the Northern Manhattan Study which found that saturated fatty was associated amongst a tendency towards an increased remove a opportunity of ischemic stroke that was excluded from the Siri-Tarino et al. meta-analysis despite evidently coming together the requirements for the inclusion criteria.31

The Problem of Reductionism

The illness promoting properties of saturated beast fatty cannot live ascribed purely to the exchange of saturated fatty for other macronutrients, but too to other nutritional factors including the content of dietary cholesterol, ruminant trans-fat and the lack of dietary fiber in addition to other phytonutrients. For example, a written report on an evidently wellness witting population included inwards the Siri-Tarino meta-analysis found that land saturated fatty was associated amongst 2.77 bend increased remove a opportunity of coronary pump illness which was the value used inwards the meta-analysis, the association for beast fatty was fifty-fifty stronger, a 3.29 bend increased risk.32

In the pooled analysis of eleven large cohort studies, compared to saturated fat, monounsaturated fats which was predominantly derived from beast fatty was associated amongst the greatest increased remove a opportunity of coronary events out of all the studied macronutrients. Furthermore this pooled analysis adjusted for dietary fiber, dietary cholesterol in addition to perchance ruminant trans-fat, which too needs to live taken into consideration every bit this could induce got potentially underestimated the adverse effects of increasing saturated beast fatty intake at the expense of whole flora foods.43 

This was unfortunately non the concluding fourth dimension that the researchers of an manufacture influenced written report would release a newspaper that has the potential to jeopardize the wellness of so many. What is too unfortunate is that many cholesterol skeptics induce got too chosen to exploit these findings inwards an endeavor to advocate illness promoting diets to an uninformed audience. Follow-up posts inwards this serial volition critically examine other lines of bear witness of the diet-heart hypothesis that cholesterol skeptics induce got chosen to misinterpret in addition to exploit inwards an endeavor to confuse the full general population. 

Diet-Heart Posts

Part II - Diet-Heart: Saturated Fat in addition to Blood Cholesterol

Part III - Diet-Heart: The Role of Vegetarian Diets inwards the Hypothesis
Part IV - Cracking Down on Eggs in addition to Cholesterol
Part V - Cracking Down on Eggs in addition to Cholesterol: Part II


Please post whatsoever comments inwards the Discussion Thread. 

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