Tag Archives: cholesterol

Saturated fat, does it matter?

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Recommendations to reduce saturated fat consumption have pervaded our media since the AHA published its first dietary guidelines for the American public in 1961. The AMA at first opposed the recommendations but the AHA pushed on. The guidelines encouraged substitution of polyunsaturates for saturated fat. The guidelines were presented in a two page report with 1/2 page of references. A subsequent independent review of those references revealed that 1/2 of them did not support the recommendations, details, details.

My last blog looked at a meta-analysis of the major studies subsequently published on this topic and found that implementation of that recommendation does not reduce heart attacks or cardiac deaths and in fact there was a trend (not statistically significant) for worse outcomes associated with substituting PUFA (polyunsaturated fatty acids, primarily linoleic acid) for SFA (saturated fatty acids).

Please note that we are talking hard endpoints here, death and heart attack. So much of the literature that consumes this issue only looks at the effect on so called risk factors. When you actually look at the clinical outcomes (death, heart attack, stroke)  there is no benefit demonstrated when saturated fats are reduced.

In 1966 the makers of Mazola Corn Oil and Mazola Margarine sponsored publication of Your Heart Has Nine Lives, a book advocating the substitution of vegetable oils for butter and other “artery clogging” saturated fats.

The history of this campaign to demonize SFA and glorify PUFA is well described in Gary Taubes Good Calories, Bad Calories, as well as in Mary Enig’s essay The Oiling of America. I would encourage you to read both.  The latter is available on line as is Gary Taubes’ famous essay What if its all a big fat lie?

http://www.westonaprice.org/know-your-fats/the-oiling-of-america

In 2010 a highly respected lipid research group published what should have been a wake-up call study for the medical profession.

Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease.

The data included 5 to 23 years follow up on 347,747 subjects. 11,006 developed coronary heart disease or stroke. Intake of saturated fat was not associated with an increased risk of coronary heart disease (CHD), stroke, or  cardiovascular disease (CVD =CHD plus stroke).

“there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”

To be clear, association (statistical correlation) does not prove or disprove causation, but if such a large amount of data from prospective studies shows no statistically significant correlation, than a causative theory should be rejected until and unless randomized controlled clinical trials suggest otherwise.

This study should have created a tsunami in the media and in the medical community but it hardly caused a ripple in the pond. Michael Eades explains why in an excellent post here.

http://www.proteinpower.com/drmike/lipid-hypothesis/eat-less-move-die-anyway/

The editors of the journal published a scathing rebuke of the authors but could not find anything wrong with the data and conclusions except that the data refuted their belief system. Busy physicians tend to read the editorials and place more credence in an editorial than in a study that questions or refutes a major thesis.

Lets look at some other studies that considered hard clinical endpoints.

Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial.

The objective of this study was:

“To test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk.”

This study was a randomized controlled trial of 48,835 postmenopausal women aged 50-79 years of diverse backgrounds and ethnicity.

“RESULTS: By year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d).”

Did this decrease heart attacks or strokes? NO

“The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05).”

Now lets look at a study where women were followed after a heart attack to see if reducing saturated fat helped.

Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr. 2004 Nov;80(5):1175-84.

In this study quantitative coronary angiography was performed at baseline and after mean follow up of 3.1 years. 2243 coronary artery segments in 235 women were studied.

Here is what they found.

  • a higher saturated fat intake was associated with a smaller decline in mean minimal coronary diameter (P = 0.001) and less progression of coronary stenosis (P = 0.002) during follow-up
  • Carbohydrate intake was positively associated with atherosclerotic progression (P = 0.001), particularly when the glycemic index was high
  • Polyunsaturated fat intake was positively associated with progression (of coronary atherosclerosis) when replacing other fats (P = 0.04) but not when replacing carbohydrate or protein
  • Monounsaturated and total fat intakes were not associated with progression. (extra virgin olive oil and macadamia nuts are rich in monounsaturated fat)

The P values cited demonstrate unequivocal statistical significance for all of these associations.

So intake of carbohydrate and polyunsaturated fat was positively associated with progression of coronary atherosclerosis. Conversely, saturated fat intake was associated with less progression of coronary stenosis.  Again, I must point out that association does not prove or disprove causation. Nevertheless, there have been no prospective studies that demonstrate an association between saturated fat consumption and cardiovascular events (real clinical endpoints). Here we have data that show a negative association with saturated fat but positive association with carbohydrate and polyunsaturated fat consumption.

The logic has always been that substituting PUFA for SFA reduces cholesterol levels (short term studies) and therefore it should reduce heart attacks and strokes. But if you search the medical literature you find that the overwhelming body of data shows no reduction in hard clinical outcomes by reducing saturated fat, in fact just the opposite is true as in the two Ramsden studies cited in my previous post.

Uffe Ravnskov has pointed out that the proponents of the dietary  saturated fat-cholesterol theory often times misrepresent the data from published studies and cite those studies in support of the theory when in fact the data actually refute the theory. (as was the case for the AHA’s first dietary recommendations demonizing saturated fat in 1961) Uffe’s letters to the editor have been a nuisance to the proponents of that theory for decades.

An exhaustive review of the literature by Ravnskov was published in 1996. The summary deserves a complete quotation here.

J Clin Epidemiol. 1998 Jun;51(6):443-60.

The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease.

Source

uffe.ravnskov@swipnet.se

Abstract

A fat diet, rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA), is said to be an important cause of atherosclerosis and cardiovascular diseases (CVD). The evidence for this hypothesis was sought by reviewing studies of the direct link between dietary fats and atherosclerotic vascular disease in human beings. The review included ecological, dynamic population, cross-sectional, cohort, and case-control studies, as well as controlled, randomized trials of the effect of fat reduction alone. The positive ecological correlations between national intakes of total fat (TF) and SFA and cardiovascular mortality found in earlier studies were absent or negative in the larger, more recent studies. Secular trends of national fat consumption and mortality from coronary heart disease (CHD) in 18-35 countries (four studies) during different time periods diverged from each other as often as they coincided. In cross-sectional studies of CHD and atherosclerosis, one group of studies (Bantu people vs. Caucasians) were supportive; six groups of studies (West Indians vs. Americans, Japanese, and Japanese migrants vs. Americans, Yemenite Jews vs. Yemenite migrants; Seminole and Pima Indians vs. Americans, Seven Countries) gave partly supportive, partly contradictive results; in seven groups of studies (Navajo Indians vs. Americans; pure vegetarians vs. lacto-ovo-vegetarians and non-vegetarians, Masai people vs. Americans, Asiatic Indians vs. non-Indians, north vs. south Indians, Indian migrants vs. British residents, Geographic Study of Atherosclerosis) the findings were contradictory. Among 21 cohort studies of CHD including 28 cohorts, CHD patients had eaten significantly more SFA in three cohorts and significantly less in one cohort than had CHD-free individuals; in 22 cohorts no significant difference was noted. In three cohorts, CHD patients had eaten significantly more PUFA, in 24 cohorts no significant difference was noted. In three of four cohort studies of atherosclerosis, the vascular changes were unassociated with SFA or PUFA; in one study they were inversely related to TF. No significant differences in fat intake were noted in six case-control studies of CVD patients and CVD-free controls; and neither total or CHD mortality were lowered in a meta-analysis of nine controlled, randomized dietary trials with substantial reductions of dietary fats, in six trials combined with addition of PUFA. The harmful effect of dietary SFA and the protective effect of dietary PUFA on atherosclerosis and CVD are questioned.

That was published in 1998, since then the evidence remains as Uffe described it 15 years ago. More studies show no relationship between saturated fat consumption and cardiovascular death, heart attack, or stroke.

Finally, multiple autopsy studies around the world have been conducted to investigate an association between diet and atherosclerosis. None of these studies have demonstrated a positive association between degree of atherosclerosis and saturated fat intake.

Yet the AHA continues to recommend lower levels of saturated fat consumption while showing little concern for the problem of sugar and refined carbohydrates.

In my next post I will discuss why sugar and refined carbohydrates are major players in the physiology of atherosclerosis. Future posts will address the China Study, Forks Over Knives, the Ornish Diet and related topics. Additionally I will discuss why an egg a day keeps the doctor away.

Go in peace.

Bob Hansen MD.

Number Needed to Treat (NNT) website and Statin Drugs

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My 85 year old mother-in-law was placed on a statin drug two years ago by her primary care physician. She had no risk factors for coronary disease other than age, she had a prior completely normal cardiac catheterization (coronary angiogram) and was totally without symptoms before being placed on the statin. Within weeks she developed muscle pain and weakness, suffered fatigue and overall felt poorly. I convinced her to stop the statin and within a few weeks she felt great. I see similar scenarios frequently in the pain clinic. I personally suffered severe statin induced myopathy pain from two different statins (in the days before enlightenment) and gratefully recovered when I stopped the drug each time. I have since learned more about coronary artery disease, cholesterol metabolism, statins, and related topics.

There is a great website that analyzes data from multiple studies to estimate the number of patients needed to treat in order to help and/or harm a patient. Two such analyses on this website are the NNT with statin drugs for five years to achieve certain results. They analyze data  in patients without known coronary artery disease (primary prophylaxis) and in patients with known coronary artery disease (secondary prophylaxis).

Here is the website:

TheNNT

Here is the page for primary prophylaxis:

Statins for Heart Disease Prevention (Without Prior Heart Disease) | TheNNT

Here is the link to the page on secondary prophylaxis:

Statins for Heart Disease Prevention (With Known Heart Disease) | TheNNT

Here are the results for primary prophylaxis.

“In Summary, for those who took the statin for 5 years:

  • 98% saw no benefit
  • 0% were helped by being saved from death
  • 1.6% were helped by preventing a heart attack
  • 0.4% were helped by preventing a stroke
  • 1.5% were harmed by developing diabetes*
  • 10% were harmed by muscle damage

In Other Words:

  • None were helped (life saved)
  • 1 in 60 were helped (preventing heart attack)
  • 1 in 268 were helped (preventing stroke)
  • 1 in 67 were harmed (develop diabetes*)
  • 1 in 10 were harmed (muscle damage)”

Here are the results for secondary prophylaxis.

“In Summary, for those who took the statin for 5 years:

  • 96% saw no benefit
  • 1.2% were helped by being saved from death
  • 2.6% were helped by preventing a repeat heart attack
  • 0.8% were helped by preventing a stroke
  • 0.6% were harmed by developing diabetes*

In Other Words:

  • 1 in 83 were helped (life saved)
  • 1 in 39 were helped (preventing non-fatal heart attack)
  • 1 in 125 were helped (preventing stroke)
  • 1 in 167 were harmed (develop diabetes*)”

If anything, the side effects (harm) are understated and the authors acknowledge this because many of the studies do not adequately report side effects and complications. (The studies were funded in part or in totality by the pharmaceutical company that makes the drug and that is a problem as discussed below)

Association of funding and conclusions in randomized dr… [JAMA. 2003] – PubMed – NCBI

It is rare that this sort of analysis would be presented to a patient in the physician’s office to help a patient decide whether the risks and benefits are acceptable. (I provide patients with this data on a multi-page handout with significant narrative and explanation when I diagnose statin myopathy.)

The obsession that American physicians have with cholesterol (another topic to be addressed in future posts) creates a knee-jerk reaction to a lab value that results too often in muscle damage and pain and sometimes cognitive impairment.

My experience in the pain clinic has been that the % of elderly with statin induced muscle damage and/or muscle pain is much higher. When I suggest that the patient stop the statin drug because they are suffering disabling pain and possibly permanent muscle damage they often return at the next visit to tell me they were started on a different statin drug. Most patients who suffer this complication will have a repeat of the same complication when placed on a different statin drug. This complication can cause permanent damage.

In the medical literature, many studies presented as “primary prophylaxis” are not truly primary prophylaxis because there are some patients included that have known diagnosed coronary disease. This tainted data is then presented as if it were a true primary prophylaxis study.

A more recent study purported to demonstrate once and for all that statins in primary prophylaxis can save lives. Unfortunately, there were problems with this study as well. Here is an excerpt from a commentary in the publishing journal:

“There are reasons to be cautious about the findings of the meta-analysis by Taylor and colleagues. As the authors note, all but 1 of the trials were partly or fully funded by pharmaceutical companies. Trials funded by for-profit organizations are more likely to recommend the experimental drug than are trials funded by nonprofit organizations (4). Further, adverse event reporting in the original trials was poor, with few details about type or severity, and quality of life was rarely assessed. Some adverse events, such as cognitive impairment, are rarer and not assessed.”

Disappointingly, the commentary failed to point out that the study data again included some patients with diagnosed coronary artery disease. (up to 10%).

Here are the authors own words.

“We included randomized controlled trials of statins versus placebo or usual care control with minimum treatment duration of one year and follow-up of six months, in adults with no restrictions on total, low density lipoprotein (LDL) or high density lipoprotein (HDL) cholesterol levels, and where 10% or less had a history of CVD.”

Once again we have a “primary prophylaxis” meta-analysis that is not really a primary prophylaxis study. It never seems to end.

When drug companies fund studies the conclusions often overstate the benefit and understate the risks. If you do not look for a side effect or complication, you will not find one. Here is an excerpt from a large study that look at the issue of bias in drug company sponsored research.

“CONTEXT:

Previous studies indicate that industry-sponsored trials tend to draw proindustry conclusions.

OBJECTIVE:

To explore whether the association between funding and conclusions in randomized drug trials reflects treatment effects or adverse events.

CONCLUSIONS:

Conclusions in trials funded by for-profit organizations may be more positive due to biased interpretation of trial results. Readers should carefully evaluate whether conclusions in randomized trials are supported by data.”

Association of funding and conclusions in randomized dr… [JAMA. 2003] – PubMed – NCBI

There are many ways that authors can present data to give the appearance of success. A more recent study published in Lancet alleged to demonstrate benefit (death prevention) for statins in primary prophylaxis.

Here it is.

The effects of lowering LDL cholesterol with statin therapy in people at low risk of vascular disease: meta-analysis of individual data from 27 randomised trials : The Lancet

But when you drill down into the data you  discover a mechanism of deception. The benefits reported in the paper applied only to patients whose cholesterol dropped significantly. Looking at all patients in the study who took the statin did not result in decreased death rates. Selecting those whose cholesterol dropped 40 points did show death prevention benefit. They presented risk reduction per unit of cholesterol reduction. From a scientific point of view this is less than honest. The authors simply demonstrated that patients who responded to the drug benefited.

DUH***All previous studies that simply compared patients on statins vs. those not on statins (primary prophylaxis) showed no prevention of death. This is an important distinction, The cost implications of putting low risk individuals on statins are enormous. Statins also rarely can cause death (from rhabdomyalysis) and frequently caused harm.  One comment about this studies’ conclusions was titled “Statins for all by the age of 50 years?” That frightens me.

The mechanism of statin drug benefits are likely related to many known potentially beneficial physiologic effects, not from a reduction of cholesterol. As you will learn in future posts, cholesterol reduction in and of itself is almost meaningless. The amount of circulating cholesterol in your blood is not the problem. The problem is much more complex and relates in part to the oxidation of LDL particles, which has little to do with the amount of cholesterol carried in those particles. Other important factors include systemic inflammation and the response of the innate immune system to factors such as circulating LPS which in turn reflects intestinal permeability. I apologize for the sudden onslaught of abbreviations and medical terms but stay tuned and you will learn what they all mean.

Finally, in the secondary prophylaxis group, the benefits of statin drug use are equivalent to the benefits achieved with exercise-based cardiac rehabilitation following a heart attack. Cardiac rehab offers many benefits in addition to saving lives, produces no significant negative side effects, and improves quality of life and sense of well-being. Many patients on statins feel lousy.

Efficacy of exercise-based cardiac rehabilitation… [Am Heart J. 2011] – PubMed – NCBI

In my next post I will discuss saturated fat  and coronary artery disease. This issue represents the crux of controversy in the heart-healthy diet debate which most physicians and the AHA consider clarified (eat less saturated fat). You already know generally what I have to say about that if you have read my Manifesto page. The next post will expand on the saturated fat section in the Manifesto. Subsequent posts will discuss cholesterol, LDL cholesterol, LDL particle number, oxidized LDL and glycated LDL (the last two are referred to as modified LDL)

Bob Hansen MD