Early atherogenesis and visceral fat in obese adolescents

 

Early atherogenesis and visceral fat in obese adolescents

A H Slyper, H Rosenberg, A Kabra, M J Weiss, B Blech, S Gensler and M Matsumura

Abstract

Background/Objectives:

 

Little information is available as to the cause of increased thickening of the intima-media of the carotid artery (cIMT) in the pediatric population. Therefore, cIMT was compared in obese adolescents and normal-weight controls, and associations between cIMT and lipid and non-lipid cardiovascular risk factors were assessed.

Subjects/Methods:

 

Subjects included 61 obese non-diabetic male and female volunteers aged 12–18 years inclusive with a body mass index (BMI) >95th percentile for age and 2-h blood glucose <200 class="mb" span=""> 

mg dl⁻¹ matched to 25 normal-weight control volunteers with normal glucose levels. Each subject underwent a 2-h glucose tolerance test and measurement of hemoglobin A1c, ultrasensitive C-reactive protein, fasting insulin, blood lipids, visceral, subcutaneous abdominal and hepatic fat, and cIMT.

Results:

 

Maximum cIMT was 0.647±0.075 mm in the obese subjects versus 0.579±0.027 mm in normal-weight controls (P<0 .001="" 2-h="" and="" assessment="" between="" bmi="" cholesterol="" cimt="" correlations="" difference="" fasting="" female="" glucose="" hdl="" high-density="" homeostasis="" in="" insulin="" ldl="" lipoprotein="" low-density="" male="" maximum="" model="" no="" significant="" sub="" subjects.="" there="" total="" very="" was="" were="" z-score="">2

cholesterol, HDL₃ cholesterol, triglycerides, remnant lipoprotein cholesterol, intermediate-density lipoprotein cholesterol, lipoprotein(a), apoprotein B100, abdominal subcutaneous fat volume, visceral fat volume and hepatic phase difference. On multiple regression analysis, visceral fat was the most significant predictor of maximum cIMT. Two-hour blood glucose, HOMA and systolic blood pressure were also significant predictors of maximum cIMT.

Conclusions:

 

cIMT was increased in the obese adolescents compared with the normal-weight-matched controls. Visceral fat was a key predictor of arterial wall thickening in these subjects. The results suggest that the focus of cardiovascular disease prevention in the adolescent obese should be visceral obesity, and not blood lipids or lipid subclasses.

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International Journal of Obesity (23 January 2014) | doi:10.1038/ijo.2014.11

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So is niacin a dead drug? Dayspring

Commentary on Niacin’s Effect on Lp(a) in AIM HIGH

Here are my thoughts as a clinical lipidologist (By: Thomas Dayspring, MD, FACP, FNLA, NCMP)

We must get apoB (LDL-P) to goal in all at-risk patients. Lifestyle therapies and statins are the mainstay of therapy. However residual risk is high if apoB (LDL) remains elevated despite at-goal LDL-C, non-HDL-C), any level of HDL-C or if Lp(a) mass is elevated.

So I would have no hesitancy in adding niacin to high and very high risk patients who have not achieved apoB (LDL-P) goals with whatever therapies they are using or using niacin as a monotherapy in those intolerant of other apoB lowering meds.

Data from HPS THRIVE 2 (discussed in a recent commentary) suggested statin plus ezetimibe was better at event reduction than statin plus niacin [9]. In view of that and the very significant side effects reported in HPS THRIVE 2 [bleeding (GI, intracranial, other) in the niacin group: 326 (2.5%) to 238 (1.9%) and infection 1031(8%) to 853 (6.6%)] [3] makes niacin a tertiary or quaternary add-on drug (some may prefer the bile acid sequestrant colesevelam as an apoB lowering medication).
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Niacin’s Effect on Lp(a) in AIM HIGH - Dayspring

Commentary on Niacin’s Effect on Lp(a) in AIM HIGH
    

By: Thomas Dayspring, MD, FACP, FNLA, NCMP

 

In 2013 we have already published two commentaries on niacin (Commentary on Niacin vs Ezetimibe as add on to Statin) and (Examination of the Recently Announced Preliminary Results of the HPS2-THRIVE Study), specifically extended release available as Niaspan, a seemingly potent lipid- and lipoprotein-modulating drug that dates back to the 1960’s. Initially it was used to reduce elevated cholesterol levels but eventually it was found to also raise HDL-C which for a variety of reasons was assumed to be very desirable (thought being that if low HDL-C is a strong CV risk factor, then raising it must be beneficial).  Also of interest was niacin’s ability to significantly reduce lipoprotein (a) mass [Lp(a)]. Indeed, a group entitled European Atherosclerosis Society Consensus Panel issued a statement strongly advising niacin be used for CV benefits in patients with elevated Lp(a) [1]. Interestingly that panel noted there was virtually no clinical trial support for this recommendation other than the fact that niacin does indeed reduce Lp(a) mass. Most lipidologists agreed with the belief that even if reducing Lp(a) does not matter, niacin would at least reduce apolipoprotein B (apoB) which is seemingly always desirable. NCEP ATP-III simply advocated achieving LDL-C goals in persons with risk related to Lp(a) issues. 

 

 

 

 

Recent trials [The Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes (AIM HIGH) and large Heart Protection Study 2: Treatment of HDL to Reduce the Incidence of Vascular Events  (HPS THRIVE 2)] have not shown additional event reduction in well-treated patients with stable CHD related to adding niacin to a statin or statin/ezetimibe regimen [2,3]. To say the results of those studies were a shock to the lipidology community is an understatement. AIM HIGH (all of the patients had low HDL-C at baseline) was published first and for those who believed niacin’s benefit was related to raising HDL-C, the results were a punch to the jaw. Despite a substantial (25%) HDL-C increase (remember the old well accepted but never proven caveat that for every 1% rise in HDL-C there is a 3% event reduction) there was no CV outcome improvement. The usual side effects associated with niacin were present including a questionable nonsignificant rise in ischemic stroke. Then along came the still not published HPS THRIVE 2 (baseline HDL-C was not an enrollment criteria) where again the addition of niacin to a statin or statin/ezetimibe regimen provided no additional outcome benefit. Common to both AIM HIGH and HPS THRIVE 2 was the fact that the lifestyle with statin or statin/ezetimibe had normalized LDL-C, non-HDL-C and apoB. Thus niacin was being added to patients who were at those goals (keeping in mind that there is no NCEP ATP-III goal for HDL-C). Should we really have expected niacin, whose primary mechanism of action is to lower apoB (or its lipid surrogates) to do anything to CV events in persons with normal apoB?  The answer is yes if raising HDL-C or lowering Lp(a) mass is critical to event reduction (well accepted concepts that have never ever been proven in any type of trial). Well we may have those answers now and at this point one has to reasonably conclude the evidence is strong that in patients on LDL-receptor inducing drugs (statins or statin + ezetimibe) raising HDL-C (note – niacin also raises apoA-I, but not apoA-II or total HDL-P) [4] or reducing Lp(a) mass with niacin provides no benefit in folks who are at apoB (LDL-C, non-HDL-C) goal.

 

In AIM HIGH baseline apoB and apoA-I levels were low and baseline Lp(a) was elevated at 33.8 nmol/L [using Caucasian adult data from Framingham as a comparator, Lp(a) averaged 20 nmol/L]. Nearly 30% of AIM HIGH patients had severe Lp(a) elevations > 100 nmol/L compared to 20% of Framingham cohort. The addition of niacin to statin or statin + ezetimibe raised HDL-C by 25%, apoA-I by 7% and reduced LDL-C by 12%, TG by 30% and apoB by 13%. [5]

 

Lp(a) as expected was significantly associated with CV events despite the fact that LDL-C was at goal and thus elevated Lp(a) is associated with residual risk. A one standard deviation of Lp(a) was associated with a 21% increase in CV risk. There was a 21% overall reduction [but with a 20%, 39% and incredible 64% decreases in patients at the 50^th, 75^th and 90^th percentile cut points] in Lp(a) in the niacin group compared to 6% in placebo group. So the higher the Lp(a) level, the more dramatic was niacin’s ability to lower it.  Here is the shocker: there was no difference in event rate between those on or not on niacin (remember all were statin or statin + ezetimibe) DESPITE GREATER DECREASES in Lp(a) for those using niacin. Even in those in the highest Lp(a) quartile (> 125 nmol/L) there was no reduction in events when niacin was added.

 

So where do we stand with niacin? There is no level one evidence anywhere supporting the use of niacin to reduce clinical events: The Coronary Drug Project (CDP) is often quoted as proof of niacin’s efficacy but few realize that niacin monotherapy (high dose of immediate release preparation) had no impact on the primary endpoint of the study (mortality): thus the benefit of reducing non-fatal myocardial infarction (a secondary endpoint) makes this benefit hypothesis generating [6].Of course there is the famous 15 year follow up of CDP which encompassed 6 years of the trial where niacin was used and then a subsequent 9 year period off niacin. Mortality was significantly reduced in that post hoc analysis (data derived not from examination or in person review but questionnaires sent to participants): this is the weakest data imaginable [7]. So this supposedly late benefit of niacin is in fact analysis of post hoc follow data up from a trial where niacin failed to reduce the primary endpoint. If niacin was a new drug, it would have no prayer of gaining FDA approval based on the CDP. Several subsequent trials using angiographic or CIMT endpoints showed niacin monotherapy or combination with bile acid sequestrants or statins showed imaging benefit. One small (~500 patients) open-label outcome trial (Stockholm Ischemic Heart Disease Secondary Prevention Trial), combining clofibrate and IR niacin did reduce clinical events with statistical significance [8].

 

In my opinion niacin became a major lipid drug because of its ability to raise HDL-C and to lower Lp(a) and not for what is likely its real mechanism of action, namely lowering LDL-C and apoB and LDL-P. After extended-release niacin (Niaspan) hit the market, it was also heavily promoted because of its ability to increase both HDL and LDL size. KOS made a fortune by promulgating those messages as it seemingly made so much sense. Of course over time, we have learned that influencing LDL or HDL particle size or raising HDL-C and apoA-I has no effect on outcomes. Looking at lipid/lipoprotein risk factors in 2013 the outcome evidence only supports lowering apoB (LDL-P) or perhaps raising total HDL-P. At this time unfortunately, there is no support for reducing Lp(a) with niacin: admittedly the Lp(a) data from the much larger HPS THRIVE 2 study of 25,000 patients is pending.  

 

So is niacin a dead drug? Here are my thoughts as a clinical lipidologist: We must get apoB (LDL-P) to goal in all at-risk patients. Lifestyle therapies and statins are the mainstay of therapy. However residual risk is high if apoB (LDL) remains elevated despite at-goal LDL-C, non-HDL-C), any level of HDL-C or if Lp(a) mass is elevated. So I would have no hesitancy in adding niacin to high and very high risk patients who have not achieved apoB (LDL-P) goals with whatever therapies they are using or using niacin as a monotherapy in those intolerant of other apoB lowering meds. Data from HPS THRIVE 2 (discussed in a recent commentary [ADD LINK]) suggested statin plus ezetimibe was better at event reduction than statin plus niacin [9]. In view of that and the very significant side effects reported in HPS THRIVE 2 [bleeding (GI, intracranial, other) in the niacin group: 326 (2.5%) to 238 (1.9%) and infection 1031(8%) to 853 (6.6%)] [3] makes niacin a tertiary or quaternary add-on drug (some may prefer the bile acid sequestrant colesevelam as an apoB lowering medication).

 

What about our patients with elevated Lp(a) mass or Lp(a)-P? The only therapy that has so far shown an inkling of success is LDL apheresis. For now we should all try to lower apoB (LDL-P as aggressively as possible and that often requires multiple combination therapies. What about future drugs: just published is the  data the PCSK9 monoclonal antibody AMG 145 reduces Lp(a) by 32% in patients on statins [10]. There is also promising data that the remaining CETP inhibitors also reduce Lp(a) but the reality is that until such reductions by these drugs are linked to outcome benefit they are of hypothetical interest. Hopefully in the future there will also be development of an apoprotein (a) antisense oligonucleotide inhibitor. 

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References:

[1] European Atherosclerosis Society Consensus Panel. Lipoprotein(a) as a cardiovascular risk factor: current status. European Heart Journal 2010;31:2844–2853.

[2] The AIM-HIGH Investigators Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy. N Engl J Med 2011;365:2255-67.
[3] Presentation by Jane Armitage on behalf of the HPS2 THRIVE group to the National Lipid Association Annual Scientific sessions, Las Vegas NV June 2013.

[4] Otvos, JD.The surprising AIM-HIGH results are not surprising when viewed through a particle lens. Journal of Clinical Lipidology (2011) 5, 368–370.

[5] John J. Albers, et al. Relationship of Apolipoproteins A-1 and B, and Lipoprotein (a) to Cardiovascular Outcomes in the AIM-HIGH Trial in press JACC 10.1016/j.jacc.2013.06.051

[6] Coronary Drug project group. Clofibrate and Niacin in Coronary Heart Disease. JAMA 1975;231:360-381.
[7] Fifteen Year Mortality in Coronary Drug Project Patients: Long Term Benefit with Niacin. JACC 1986;8:1245-55.
[8] Reduction of Mortality in the Stockholm Ischaemic Heart Disease Secondary prevention Study by Combined Treatment with Clofibrate and Nicotinic Acid. Acta Med Scand 1988;223:405-418.[9] Masana, A. Cabré, N. Plana. HPS2-THRIVE results: Bad for niacin/laropiprant, good for ezetimibe? Atherosclerosis 2013;229:449-450.

[9] Masana, A. Cabre, N. Plana. HPS2-THRIVE results: Bad for Niacin/laropiprant, good for ezetimibe? Atherosclerosis 2013; 229:449-450.

[10] Nihar R. Desai, et al. AMG145, a Monoclonal Antibody Against Proprotein Convertase Subtilisin Kexin Type 9, Significantly Reduces Lipoprotein(a) in Hypercholesterolemic Patients Receiving Statin Therapy. (Circulation. 2013;128:962-969.)

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Dietary Fats and Health - Lawrence

Dietary Fats and Health: Dietary Recommendations in the Context of Scientific Evidence¹

Glen D. Lawrence^* Department of Chemistry and Biochemistry, Long Island University, Brooklyn, NY

*To whom correspondence should be addressed. E-mail: lawrence@liu.edu.

 

Abstract

Although early studies showed that saturated fat diets with very low levels of PUFAs increase serum cholesterol, whereas other studies showed high serum cholesterol increased the risk of coronary artery disease (CAD), the evidence of dietary saturated fats increasing CAD or causing premature death was weak. Over the years, data revealed that dietary saturated fatty acids (SFAs) are not associated with CAD and other adverse health effects or at worst are weakly associated in some analyses when other contributing factors may be overlooked. Several recent analyses indicate that SFAs, particularly in dairy products and coconut oil, can improve health. The evidence of ω6 polyunsaturated fatty acids (PUFAs) promoting inflammation and augmenting many diseases continues to grow, whereas ω3 PUFAs seem to counter these adverse effects. The replacement of saturated fats in the diet with carbohydrates, especially sugars, has resulted in increased obesity and its associated health complications. Well-established mechanisms have been proposed for the adverse health effects of some alternative or replacement nutrients, such as simple carbohydrates and PUFAs. The focus on dietary manipulation of serum cholesterol may be moot in view of numerous other factors that increase the risk of heart disease. The adverse health effects that have been associated with saturated fats in the past are most likely due to factors other than SFAs, which are discussed here. This review calls for a rational reevaluation of existing dietary recommendations that focus on minimizing dietary SFAs, for which mechanisms for adverse health effects are lacking.

 

Introduction

Since the Framingham Heart Study reported that high serum cholesterol was a major risk factor for coronary heart disease (1), there has been an aggressive campaign in the medical community to decrease serum cholesterol. It has been a widely accepted belief that dietary saturated fats and dietary cholesterol cause an increase in serum total cholesterol, as well as LDL-cholesterol (LDL-C)² and thereby increase the risk of heart disease if consumed (2). Over the years, it became clear that high levels of LDL circulating in the blood are susceptible to lipid peroxidation, which results in the oxidized LDL being scavenged by macrophages lining certain arteries, particularly around the heart, leading to atherosclerosis (3). Although this mechanism provides a role for high serum LDL-C causing atherosclerosis, evidence of the involvement of saturated fats is lacking, even though it is well established that a diet high in saturated fat increases serum cholesterol and a diet high in polyunsaturated oil decreases serum cholesterol (4, 5). In fact, PUFAs are the components that are oxidized and generate antigenic substances that are recognized by immune cells for clearance of oxidized LDL in atherogenesis (6–8).

                 

Numerous reports and reviews in recent years have begun to call the perceived pernicious effects of dietary saturated fatty acids (SFAs) into question. The purpose of this review is to summarize the scientific understanding as it relates to dietary fats in health and disease, particularly with regard to the innocuous nature of SFAs and the physiological effects that have implicated PUFAs in numerous disorders and diseases. The role of dietary fats in cardiovascular disease (CVD) and many other diseases is complex, yet there is a powerful inertia that has allowed the saturated fat doctrine to endure.

Dietary fatty acids and serum cholesterol

Dietary fat studies in the mid-20th century stressed the relationship of dietary SFAs and PUFAs to serum cholesterol levels with an aim toward decreasing the likelihood of the development of coronary artery disease (CAD) and premature death (4, 5). Once lipoprotein fractions were separated in the blood, it became evident that LDL and VLDL were the carriers of cholesterol that were most closely associated with risk of heart disease (9). Later it was found that the ratio of total serum cholesterol to HDL-C was a better indicator of heart disease risk (10). By the 1990s, the mechanisms by which dietary fats and specific types of fatty acids were regulating serum cholesterol and lipoproteins were beginning to be revealed.

                    

A family of proteins known as sterol regulatory element binding proteins (SREBPs) were discovered in the early 1990s. These proteins move to the nucleus in cholesterol-depleted cells to alter transcription of several genes involved in lipid metabolism (11). When intracellular cholesterol levels are low, SREBP-1 promotes expression of genes for synthesis of cholesterol and LDL receptors that remove cholesterol from the circulation. When intracellular cholesterol levels are high, SREBP-1 is not activated by protease cleavage, and the genes for cholesterol production and LDL receptors are downregulated. SREBP-1 also activates promoters for genes involved in fatty acid synthesis and lipid storage (12). PUFAs, particularly docosahexaenoic acid and others to a lesser extent, regulate expression of the SREBP genes (13, 14). Consequently, when PUFAs are present, there is less expression of SREBPs and enzymes for cholesterol synthesis, and the serum cholesterol pool decreases.

                    

There appears to be a number of proteins that bind PUFAs and are involved in regulating gene expression, including a family of G protein–coupled receptors (15), as well as peroxisome proliferator–activated receptors-α and -γ, retinoid X receptors, and various other nuclear receptors (16). The liver uses a variety of these receptors or sensors for PUFAs to regulate storage and utilization versus oxidation of PUFAs (17). In this way, PUFAs can stimulate fatty acid oxidation in the liver to minimize their potential for free radical oxidation in the body when their levels are high in the diet. One must keep in mind that this complex array for regulation of expression of a wide range of genes is also subject to an even more complex array of responses to dietary PUFAs and other dietary factors.

                    

Single nucleotide polymorphisms in genes for many of the above factors, as well as in genes for several apolipoproteins, TNFs, glutathione peroxidases, and other proteins result in a wide range of individual responses to dietary constituents. The consequences of such genetic variation can be either little change or very large changes in serum lipids and lipoproteins in response to diet, depending on an individual’s genetic makeup (18). However, one should not lose sight of the fact that levels of many other proteins are being altered in the process, which can give rise to a wide array of physiological responses that influence susceptibility to many unhealthy conditions, such as CVD and cancer.

                    

Short-chain SFAs, such as those in dairy fat and coconut oil, can also influence gene expression via interactions with various G protein–coupled receptors that are linked to several hormonal responses, including insulin and leptin, that regulate overall energy metabolism in the body (19). It is clear that there are numerous sensors that respond to dietary PUFAs and short- or medium-chain SFAs (20).                     

Genetic factors

Brown and Goldstein (21) received the Nobel Prize in Physiology or Medicine in 1985 for their work on genetic defects in LDL receptors of people with familial hypercholesterolemia (FH). They identified several mutations that produce nonfunctional LDL receptors, resulting in death from atherosclerosis and heart disease at an early age. Individuals with FH have serum LDL-C in excess of 300 mg/dL (or 8 mmol/L), although LDL-C may be as high as 650 mg/dL (17 mmol/L) in homozygous individuals. Goldstein and Brown (22) also identified several genes that code for other proteins involved in cholesterol transport and metabolism, such as apolipoprotein B-100 (apo B), which is a component of LDL that binds to LDL receptors. There are other proteins involved in LDL synthesis, transport, and clearance that can result in a genetic predisposition to increased serum LDL cholesterol and FH (23–25).

                    

In the early 1990s, it was discovered that men with CVD tended to have smaller HDL particles than healthy controls (26). It was later found that LDL particle size was also significantly smaller in men with CAD than in case-matched controls (27), although another study showed the ratio of total serum cholesterol to HDL-C was a better predictor of CAD risk than LDL particle size (28). A prospective, population-based cohort study also found an increased risk of CAD in middle-aged men with smaller, dense LDL particles than in men with larger LDL particles, although the relationship did not show a linear dependence on particle size (29). It later became evident that LDL particle size was influenced by several factors and was not necessarily a useful predictor of heart disease risk; the nature of LDL is influenced by both dietary and genetic factors (30).

                    

Lipoprotein (a) [Lp(a)] is a complex lipoprotein that has several properties in common with LDL. Like LDL and VLDL, Lp(a) contains apo B, but also contains highly variable forms of apolipoprotein(a) that strongly influence its atherogenicity and propensity to promote heart disease (31). The wide array of apolipoprotein(a) isoforms present in the human population may have caused some confusion regarding the role of Lp(a) in atherogenesis and CVD. The association of apo B with oxidized phospholipids was found to be dependent on Lp(a) (32). The presence of oxidized phospholipids and Lp(a) tend to be proinflammatory and promote atherogenesis.

                    

Small, dense LDL particles rarely occur as an isolated condition, but are often associated with a specific phenotype that is characterized by hypertriglyceridemia, low HDL-C, abdominal obesity, insulin resistance, and other metabolic irregularities that lead to endothelial dysfunction and susceptibility to thrombosis (33). Small, dense LDL is also more susceptible to lipid peroxidation due to changes in the lipid composition, making it more atherogenic (34). LDL particles from the atherogenic phenotype contain less cholesterol and phospholipid, but more triglyceride. This phenotype is generally referred to as phenotype B and is characterized by elevated levels of apo B, which is found in LDL and VLDL (35).

                    

There have been a host of proteins linked to lipoprotein metabolism and transport and a wide range of genetic variations identified that result in alterations of those proteins. Many are associated with HDL and larger HDL particle size, which is consistently associated with a decreased risk of CAD (36). HDL is important in reverse-cholesterol transport, bringing cholesterol from arterial deposits to the liver for processing, where it is converted to useful metabolites and eventually cleared from the body via bile secretions. A family of lipoprotein lipases, including hepatic lipase and endothelial lipase, are intimately involved in HDL metabolism. Endothelial lipase is upregulated during inflammation, a condition that increases LDL oxidation and atherogenesis (37). Genetic variation in apolipoprotein A-I, a major protein component of HDL, can result in larger but less stable HDL particles and decreased levels of circulating HDL (38). Cholesteryl ester transfer protein is generally considered to be protective, although this protein may transfer lipids from HDL to other lipoproteins that result in a less desirable serum lipid profile (39). HDL is emerging as a fascinating lipoprotein with a complex array of functions that involve both protein and lipid components. HDL has been found to influence immune function, vascular inflammation, glucose metabolism, and platelet function as well as other physiological phenomena unrelated to CVD (40).

                    

Paraoxonase 1 (PON1) is another protein associated with HDL that exhibits esterase and lactonase enzyme activity, including metabolism of toxic organophosphorus pesticides and oxidized lipids in oxidized LDL particles. The levels of PON1 activity varies tremendously among humans, which depends to a large degree on genetic variation. However, environmental factors, such as dietary antioxidant consumption, alcohol consumption, and certain drugs can also influence PON1 activity (41). Dietary olive oil can increase levels of serum PON1 in some individuals, which is genotype dependent (42), whereas MUFAs and PUFAs can inhibit PON1 enzymatic activity (43). SFAs (palmitic and myristic) had virtually no effect on PON1 enzymatic activity. A recent study found that HDL isolated from patients with CAD lacks endothelial anti-inflammatory properties, has lower PON1 enzyme activity, and does not promote endothelial nitric oxide production (44), all of which are most likely tied to genetic rather than dietary factors.

Fatty acids involved in atherogenesis and CVD

Linoleic acid makes LDL more susceptible to lipid peroxidation and subsequent deposition of the oxidized LDL in macrophages lining the arteries (45). Several lipid peroxidation products have been shown to trigger transformation of circulating monocytes to macrophages that line the arteries and ultimately become foam cells (46, 47). Lipid peroxidation products also signal cells in the arterial intima to encapsulate foam cells by surrounding them with extracellular matrix proteins and eventually calcify the matrix (48). It would stand to reason that a greater abundance of PUFAs, relative to SFAs and MUFAs, during conditions of oxidative stress would provoke atherogenesis. The fibrous cap that is formed over fatty deposits makes them inaccessible to apolipoproteins such as apolipoprotein A-I or E, which are components of HDL, the lipoprotein that removes cholesterol from these deposits (49). The protein cap is characteristic of advanced atherosclerotic plaque and erosion of this protective cap by extracellular metalloproteases can release collagen and collagen-like fragments that trigger blood platelets to initiate a blood clot, which results in myocardial infarction or stroke (3).

                    

Because saturated fats are not susceptible to lipid peroxidation, they have not been found to be involved in these mechanisms. This begs the question of how dietary polyunsaturated oils seem to lower the risk of CAD, even though many studies have shown no such effect. One important consideration is that foods that are considered sources of predominantly saturated fats, such as meats, are often cooked at high temperatures, which can induce lipid peroxidation in the minor amounts of PUFAs present in those animal products (50–52). Oxidative stress and lipid peroxidation products are known to promote heart disease, cancer, and several other chronic diseases (53, 54). High-temperature cooking can also oxidize carbohydrates, producing a range of toxic oxidation products that promote oxidative stress, type 2 diabetes, and CVD (55). The preparation and cooking methods used for foods that are traditionally classified as saturated fat foods may be producing substances from PUFAs and carbohydrates in those foods that are promoting disease.

                    

Human food preferences tend to favor foods with both fats and sugar (56), which complicates any attempts to correlate saturated fats with disease. Sugars readily undergo oxidation, with fructose generally getting oxidized many times faster than glucose, whereas sucrose is relatively resistant to oxidation (57). The oxidation products of these monosaccharides include glyoxal, methylglyoxal, and formaldehyde. Methylglyoxal has been shown to promote endothelial dysfunction as well as hypercholesterolemia in rats (58). Methylglyoxal is also associated with increased atherosclerosis and hypertension in humans (59). Formaldehyde and methylglyoxal have been implicated in endothelial injury, oxidative stress, and angiopathy (60).

                    

Many clinical studies show that there are fewer coronary events when polyunsaturated oils replace saturated fats in the diet (61). However, a recent meta-analysis found that interventions using mixed ω3 and ω6 PUFAs resulted in a significant (22%) decrease in CAD events compared with control diets with fewer PUFAs. However, interventions that used ω6 polyunsaturated oils with no ω3 PUFAs showed ∼16% more cardiovascular events compared with the control diets, although the increased number was not statistically significant (62). It would seem that even moderate amounts of ω3 PUFAs in the diet result in attenuation of inflammatory responses that are reflected in the significant reduction in coronary events observed with increasing dietary PUFAs. Of the common vegetable oils, soy oil contains ∼7% ω3 PUFAs and canola oil as much as 10% ω3 PUFAs, whereas corn, safflower, and sunflower oils generally contain <1 a="" class="xref-bibr" href="http://advances.nutrition.org/content/4/3/294.long#ref-63" id="xref-ref-63-1" pufas="">63

). Another systematic review found insufficient evidence to support an association (positive or negative) between CAD and several dietary factors, including SFAs or PUFAs, α-linolenic acid, total fat, meat, eggs, and milk (64).

Lipid peroxidation and inflammation

Lipid peroxidation is invoked as a mechanism for numerous adverse health effects, such as aging, cancer, atherosclerosis, and tissue necrosis. The greater in vivo susceptibility of ω6 PUFAs relative to the ω3 PUFAs, has placed the spotlight on these fatty acids as contributing to or exacerbating many ailments (68). The metabolism of arachidonic acid to bioactive eicosanoids is responsible for many of the biological processes that lead to inflammation. Indeed, steroidal and nonsteroidal anti-inflammatory drugs suppress inflammation by blocking the release of arachidonic acid from membranes or its subsequent metabolism to eicosanoids.

                    

Studies of inflammation in rats have found that dietary manipulation of relative amounts of ω6 PUFA precursors can have profound effects on the degree of inflammation. Predominantly SFAs in the diet result in far less inflammation than diets with either ω3 (69) or ω6 PUFAs (70). Several studies have shown that dietary supplementation with ω3 PUFAs can reduce inflammation and make patients less dependent on drug therapy to manage the pain and stiffness of arthritis (71–73). Patients should be advised to minimize their intake of ω6 oils when attempting ω3 supplementation as a therapeutic approach to reduce the inflammation of arthritis and other inflammatory syndromes (74, 75). Small amounts of ω3 supplements in a sea of dietary ω6 oils would have relatively little chance of changing the course of an inflammatory response. Because dietary saturated fats do not promote inflammation, it may be wiser to minimize ω6 PUFAs and consume more SFAs to reduce various types of inflammation; most sources of MUFAs contain significant amounts of PUFAs as well. There have been few scientific studies along these lines because of the misguided concern that saturated fats, even those from vegetable sources such as palm and coconut oil, would be detrimental to one’s health.

                    

The efficacy of ω3 supplements for inflammatory syndromes other than rheumatoid arthritis are less persuasive, although study designs are questioned regarding whether patients are advised to reduce their ω6 fatty acid intake (76). Fish oil supplements improved pulmonary function in some asthmatics (responders) but not in others (nonresponders). A relatively high ratio (10:1) of dietary ω6 to ω3 PUFAs resulted in diminished respiratory function in methacholine-provoked asthmatics, whereas a lower ratio (2:1) produced significant improvement in >40% of the study participants (77). A study in Japan showed beneficial effects of ω3 supplements in asthmatic children in a controlled hospital ward environment (78). A comparison of dietary saturated fats with polyunsaturated oils was not found in the literature for asthma studies. Such an approach would be logical for this life-threatening condition, in view of the benign nature of saturated fats and the fact that carbohydrates, especially sugars, may actually be augmenting the incidence of asthma (79).

Are low-fat, low-saturated fat diets healthier?

Studies with laboratory animals have shown that high-fat diets promote chemically induced cancers (80, 81). A study of chemically induced mammary tumors in rats found that ω6 PUFAs promoted tumor proliferation, whereas saturated fats or ω3 PUFAs did not promote tumors as much or even suppressed tumors, depending on what one uses as a reference (82, 83). Although 1 review and meta-analysis found that linoleic acid, the predominant ω6 fatty acid in vegetable oils, is not a risk factor for breast, colorectal, and prostate cancers in humans (84), there is evidence to the contrary that high intake of ω6 relative to ω3 PUFAs increases cancer risks (85–87). There are multiple processes by which ω6 fatty acids can promote carcinogenesis; production of bioactive eicosanoids from arachidonic acid is 1 mechanism (88, 89). Nonsteroidal anti-inflammatory drugs as well as cyclooxygenase-2 inhibitors can suppress tumors by inhibiting production of prostaglandins, particularly those of the ω6 variety (90). Lipid peroxides are also known to promote chemically induced tumors (91), and PUFAs are highly susceptible to lipid peroxidation.

                    

Investigators often seem to have a particular bias against saturated fats. One report showed that red meat alone was not significantly associated with colorectal cancer, although there was some increase in colorectal cancers with higher red meat intake [HR = 1.17 for highest vs. lowest intakes (95% CI = 0.92–1.49, P_-trend = 0.08)]. Processed meats were significantly associated [HR = 1.42 (95% CI = 1.09–1.86, P_-trend = 0.02)]. The authors then combined the data for red meat and processed meat to give a significant association and concluded that red and processed meat are positively associated with colorectal cancer (92). When specific types of meat were analyzed, significant risk was associated with pork [HR = 1.18 (95% CI = 0.95–1.48, P_-trend = 0.02)] and lamb [HR = 1.22 (95% CI = 0.96–1.55, P_-trend = 0.03)], but not with beef/or veal [HR = 1.03 (95% CI = 0.86–1.24, P_-trend = 0.76)]. It is interesting to note that in 1 study, beef had a much lower ratio of PUFAs to SFAs than pork, but nearly the same ratio of PUFAs to SFAs as sheep (93). The ratio of MUFAs to SFAs in beef also varies, as it does in most meats, with the ratio ranging from ∼0.8 to 1.8, depending on breed and feeding practices (94).

                    

Nitrite used in the preservation of many processed meats is known to form a carcinogen with secondary amines under acidic conditions that would prevail in the stomach (95). Others have found no association of red meat and only a very weak association of processed meat with breast cancer (96) and prostate cancer (97). Most studies find no differences in cancer risk with different types of fat, but do find associations with high levels of fat in the diet (81).

                    

A recent meta-analysis (98) reviewed 20 studies with >1 million subjects and found that red meat was not associated with CAD events [RR = 1.00 (95% CI = 0.81–1.23, P_-trend = 0.36)]. In contrast, processed meats were associated with increased incidence of CAD [RR = 1.42 (95% CI = 1.07–1.89, P_-trend = 0.04)]. This indicates that saturated fat per se is not increasing CAD events, but other factors are, such as preservatives used in processed meats or other dietary substances that are being consumed in conjunction with processed meats. It is important to keep in mind that meats generally contain as much MUFA as SFA. Others are beginning to challenge the saturated fat hypothesis with closer analyses of past studies (99–103).

                    

Campaigns were waged against tropical oils (palm and coconut oils) in the early 1980s because of their high levels of SFAs, even though palm oil contains about as much MUFAs acids as SFAs and has an ample amount of PUFAs to keep serum cholesterol low. In fact, 2 studies showed that the higher ratio of SFAs to MUFAs in palm oil (1.1:1) compared with olive oil (0.22:1) had no effect on serum lipids in healthy volunteers (104, 105). Palm oil and olive oil have similar amounts (∼10%) of PUFAs. SFAs in coconut oil increase serum HDL-C more than LDL-C to give a more favorable lipid profile relative to dietary carbohydrates (10). Claims that tropical oils with a high SFA content increase the risk of CAD lack clear scientific evidence to that effect. Indeed, countries with high intake of tropical oils have some of the lowest rates of heart disease in the world (106).

                    

Many of the shorter chain fatty acids found in milk fat and coconut oil have beneficial health effects. The shorter chain SFA in milk (C4–C12) are not only metabolized rapidly for energy in infants, but have been found to have important antiviral, antimicrobial, antitumor, and immune response functions (107). Lauric acid, which is present in milk and the most abundant fatty acid in coconut oil, is effective in preventing tooth decay and plaque buildup (108). Diets rich in coconut oils have also been shown to lower other risk factors for CAD, such as tissue plasminogen activator antigen and Lp(a) (109). The medium-chain SFAs in coconut oil and butterfat (milk) increase total serum cholesterol, but their positive effects on HDL-C are protective in many ways. There is also evidence that proteins, fats, and calcium in milk are beneficial in lowering blood pressure, inflammation, and the risk of type 2 diabetes (110, 111). Indeed, these constituents of milk have clear beneficial effects against metabolic syndrome, which is a major factor in promoting heart disease, as well as premature death from a variety of causes (112).

                    

There has been a spate of recent publications in the biomedical literature that question the negative perception that dairy fats are bad for health. One meta-analysis showed that participants in prospective studies with the highest consumption of dairy products had a lower RR for all-cause mortality as well as for CAD, stroke, and diabetes compared with the lowest intake of dairy products (113). Many of the studies included in the analysis started before low-fat milk was available on the market. Another review arrived at the same conclusion that consumption of dairy products is not associated with higher risk of CVD (100). Although prospective cohort studies often find a significant reduction in the incidence of CAD with a larger ratio of PUFAs to SFAs in the diet (114), there are often many other factors related to overall health that correlate with the unsaturated to SFA ratio, such as exercise, a healthier lifestyle, and more fiber and less sugar in the diet.

Less fat generally means more carbohydrate

It should not be surprising that substitution of carbohydrates (starches) for saturated fats in the diet has relatively little effect on serum lipids. Excess carbohydrates are converted to fats for efficient energy storage, and the human body synthesizes primarily SFAs from excess carbohydrates, although MUFAs are also formed. Consequently, from a physiological viewpoint, there is no reason to believe that replacing fat in the diet with carbohydrate at a constant caloric intake will improve the serum lipid profile significantly. Indeed, a low-fat, high-carbohydrate diet causes an increase in serum triglycerides and small, dense LDL particles (115), which are more strongly associated with CAD than serum total cholesterol or LDL-C. When dietary fat is replaced by carbohydrate without changing the fatty acid composition of the fat, there is no change in LDL-C or HDL-C, but there is an increase in serum triglycerides (116). However, if there is a higher percentage of PUFAs and lower SFAs in a low-fat diet, serum total cholesterol and LDL-C will decrease (117).

                    

Young children who consumed more fruit juice than their peers were shorter in stature and had greater BMI than their peers who drank less fruit juice (118). A trend of increased fruit juice consumption by infants and children in recent years has coincided with a decrease in milk consumption (119). The rates of childhood obesity have skyrocketed since the introduction of low-fat milk, although high fructose corn syrup (HFCS) became omnipresent in foods at the same time and is more strongly associated with obesity than dietary fat (120, 121). As stated previously, the short-chain SFAs in milk provide valuable antibacterial and antiviral activities, which would result in healthier children. The short-chain SFAs found in milk act as signaling agents in the immune system (122). Infections in children also correlated with higher levels of atherogenic oxidized LDL, as well as lower levels of HDL (123). It is possible that oxidized LDL and low HDL impart increased susceptibility to infection, although the combination of infections and an adverse serum lipid profile may both result from an undesirable diet, i.e., more sugar and fewer healthy fats.

                    

Food processors generally add large amounts of sugar to fat-free or low-fat foods to make them more palatable to consumers. Fructose is 1 dietary constituent that is consistently found to have adverse health consequences, and the larger the proportion of fructose is in the diet, the more formidable the effect. The adverse effects of fructose that have been documented include increased serum triglycerides, particularly in men (124, 125); increased serum uric acid, which is associated with gout and hypertension (126); increased lipid peroxidation (57) and increased oxidation of LDL (127); increased oxidative stress in animal models (128); greater risk of the development of metabolic syndrome, including obesity, insulin resistance, hypertension, and CVD risk (129, 130); increased nonalcoholic fatty liver disease (131); and increased systemic inflammation and associated renal disease (132).

                    

There are clearly many established physiological mechanisms by which fructose increases CVD and several other diseases. Whether the source of dietary fructose is sucrose or HFCS would seem irrelevant, although sucrose is 50% fructose, whereas the most common dietary source of HFCS (soft drinks) is generally 55% fructose and ∼43% glucose. Solutions of fructose are also highly susceptible to autoxidation, producing a host of toxic products (57), whereas sucrose is highly resistant to oxidation. The toxic products from fructose oxidation include formaldehyde and α-dicarbonyls. Although saturated fats have been implicated in many of the adverse health effects attributed to fructose, there is no scientific evidence to support a role for saturated fats in the physiological mechanisms. On the other hand, plausible mechanisms are proposed for all of the unhealthy conditions promoted by high fructose intake mentioned earlier.

                    

It turns out that a high level of fructose in the diet increases plasma triglycerides, which leads to not only increased levels of VLDL and small, dense LDL particles, but increased levels of oxidized LDL, insulin resistance, and other metabolic consequences linked to metabolic syndrome and dyslipidemia (133). The mechanisms by which fructose promotes inflammation and elevated levels of uric acid and several cytokines have been reviewed (132).                       

Conclusions

Saturated fats are benign with regard to inflammatory effects, as are the MUFAs. The meager effect that saturated fats have on serum cholesterol levels when modest but adequate amounts of polyunsaturated oils are included in the diet, and the lack of any clear evidence that saturated fats are promoting any of the conditions that can be attributed to PUFA makes one wonder how saturated fats got such a bad reputation in the health literature. The influence of dietary fats on serum cholesterol has been overstated, and a physiological mechanism for saturated fats causing heart disease is still missing.

                 

Various aldehydes produced in the oxidation of PUFAs, as well as sugars, are known to initiate or augment several diseases, such as cancer, inflammation, asthma, type 2 diabetes, atherosclerosis, and endothelial dysfunction. Saturated fats per se may not be responsible for many of the adverse health effects with which they have been associated; instead, oxidation of PUFAs in those foods may be the cause of any associations that have been found. Consequently, the dietary recommendations to restrict saturated fats in the diet should be revised to reflect differences in handling before consumption, e.g., dairy fats are generally not heated to high temperatures. It is time to reevaluate the dietary recommendations that focus on lowering serum cholesterol and to use a more holistic approach to dietary policy.

 

Acknowledgments

The sole author had responsibility for all parts of the manuscript.

 

Footnotes

• ↵1 Author disclosure: G. D. Lawrence, no conflicts of interest.
• ↵2 Abbreviations used: apo B; apolipoprotein B-100; CAD, coronary artery disease; CVD, cardiovascular disease; FH, familial hypercholesterolemia; HDL-C, HDL cholesterol; HFCS, high fructose corn syrup; LDL-C, LDL cholesterol; Lp(a), lipoprotein(a); PON1, paraoxonase 1; SFA, saturated fatty acid; SREBP, sterol regulatory element binding protein.

• © 2013 American Society for Nutrition

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Read the complete article here.

                        

Total cholesterol doesn’t matter...Cohen

Dear Pharmacist,

 

I saw Dr. Oz interview a doctor on television about cholesterol. The guest said your total cholesterol doesn’t matter and I read that in your book 6 years ago. Suzy, I take a statin, and do a “Lipid Profile” annually. Is this okay? –M.D., Austin, Texas
 

Answer: No, it’s not okay, and I’m about to shock everyone, unless you’ve read my books, then this will be review.
 

Recently I wrote a column about LDL and that we should not necessarily strive to lower it. We need to know the type and number of LDL particles. For example, Lipoprotein A or “Lp(a)” and another called apolipoprotein B or “Apo B” are two subtypes of LDL particles. These particular scores directly affect your cardiovascular risk. Do you have those numbers on your lab test? I bet you don’t.
 

In my first book, The 24-Hour Pharmacist from 2007 and many syndicated columns I’ve explained that statins are not very effective in reducing LDL particle number or Apo B and usually do not increase the size of your LDL particles, that’s why I don’t encourage them.
 

It’s confusing for consumers (and physicians who unwittingly accept drug propaganda) because studies conclude statins reduce total LDL. And yes, they do reduce “total” LDL, they are also excellent anti-inflammatories so they are not completely without merit. But I’m bent on you reducing Lp(a) and Apo B, the dangerous subtypes of LDL known to raise risk for heart attack and stroke. One day I’ll tell you which vitamin reduces those bad boys, since drugs can’t, but now, back to this testing dilemma.

I’ll never submit myself for a routine “Lipid Profile” because it would waste my money. Half the people who have heart attacks have normal total cholesterol. If your results shows a low LDL (considered the bad particle), then you may assume you’re okay but you see, a low total LDL score doesn’t say much. Your triglycerides might be through the roof! You may have a huge concentration of dangerous Lp(a) and Apo B, subtypes of LDL that are never measured in that basic lipid profile.
 

Likewise, you may be happy with your high HDL cholesterol score, (HDL is considered a good cholesterol), but what if you have the wrong kind of HDL particles? Yeah, some HDL is bad, you didn’t know that?! You’re still at very high risk. These basic “Lipid Profiles” don’t provide the crucial details. It’s like a car mechanic who you hire to fix your engine, but you only let him look at the hood of your car, he can’t open the hood to see inside!
 

The better tests, sometimes covered by insurance measure particle size, type and sometimes the actual number of LDL and HDL particles. I urge you to ask your physician to order tests from Berkeley HeartLab, a leader in this field. There’s also another one called the “VAP Test” by Atherotec Diagnostics and finally, the “NMR Lipoprofile” by LipoScience.
 

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Read the complete atricle here.

I Wish I Had Lipoprotein(a)!

Posted on August 8, 2012 by Dr. Davis

 

Why would I say such a thing? Well, a number of reasons. People with lipoprotein(a), or Lp(a), are, with only occasional exceptions:

–Very intelligent. I know many people with this genetic pattern with IQs of 130, 140, even 160+.

–Good at math–This is true more for the male expression of the pattern, only occasionally female. It means that men with Lp(a) gravitate towards careers in math, accounting, financial analysis, physics, and engineering.

–Athletic–Many are marathon runners, triathletes, long-distance bicyclists, and other endurance athletes. I tell my patients that, if they want to meet other people with Lp(a), go to a triathlon.

–Poor at hydrating. People with Lp(a) have a defective thirst mechanism and often go for many hours without drinking water. This is why many Lp(a) people experience the pain of kidney stones: Prolonged and repeated dehydration causes crystals to form in the kidneys, leading to stone formation over time.

–Tolerant to dehydration–Related to the previous item, people with Lp(a) can go for extended periods without even thinking about water.

–Tolerant to periods of food deprivation or starvation–More so than other people, those with Lp(a) are uncommonly tolerant to days without food, as would occur in a wild setting.

In short, people with Lp(a) are intelligent, athletic, with many other favorable characteristics that provide a survival advantage . . . in a primitive world.

So when did Lp(a) become a problem? When an individual with Lp(a) is exposed to carbohydrates, especially those from grains. When an evolutionarily-advantaged Lp(a) individual is exposed to carbohydrates, more than other people they develop:

–Excess quantities of small LDL particles–Recall that Lp(a) is a two-part molecule. One part: an apo(a) made by the liver. 2nd part: an LDL particle. When the LDL particle within the Lp(a) molecule is small, its overall behavior is worse or more atherogenic (plaque-causing).

–Hyperglycemia/hyperinsulinemia–which then leads to diabetes. Unlike non-Lp(a) people, these phenomena can develop with far less visceral fat. A Lp(a) male, for instance, standing 5 ft 10 inches tall and weighing 150 pounds, can have as much insulin resistance/hyperglycemia as a non-Lp(a) male of similar height weighing 50+ pounds more.

Key to gaining control over Lp(a) is strict carbohydrate limitation. Another way to look at this is to say that Lp(a) people do best with unlimited fat and protein intake.
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Read the complete article here.

The information and online tools for health can handily exceed the limited “wisdom” dispensed by John Q. Primary Care doctor.

Crossposted from Heart Scan Blog====================================================================
How far wrong can cholesterol be?

from Heart Scan Blog  by Dr. William Davis

Conventional thinking is that high LDL cholesterol causes heart disease. In this line of thinking, reducing cholesterol by cutting fat and taking statin drugs thereby reduces or eliminates risk for heart disease.

Here’s an (extreme) example of just how far wrong this simpleminded way of thinking can take you. At age 63, Michael had been told for the last 20 years that he was in great health, including “perfect” cholesterol values of LDL 73 mg/dl, HDL 61 mg/dl, triglycerides 102 mg/dl, total cholesterol 144 mg/dl. “Your [total] cholesterol is way below 200. You’re in great shape!” his doctor told him.

Being skeptical because of the heart disease in his family, had a CT heart scan. His coronary calcium score: 4390. Needless to say, this is high . . . extremely high.

Extremely high coronary calcium scores like this carry high likelihood of death and heart attack, as high as 15-20% per year. So Michael was on borrowed time. It was damn lucky he hadn’t yet experienced any cardiovascular events.

That’s when Michael found our Track Your Plaque program that showed him how to 1) identify the causes of the extensive coronary atherosclerosis signified by his high calcium score, then 2) correct the causes.

The solutions, Michael learned, are relatively simple:

–Omega-3 fatty acid supplementation at a dose sufficient to yield substantial reductions in heart attack.
–”Normalization” of vitamin D blood levels (We aim for a 25-hydroxy vitamin D level of 60-70 ng/ml)
–Iodine supplementation and thyroid normalization
–A diet in which all wheat products are eliminated–whole wheat, white, it makes no difference–followed by carbohydrate restriction.
–Identification and correction of all hidden causes of coronary plaque such as small LDL particles and lipoprotein(a)

Yes, indeed: The information and online tools for health can handily exceed the limited “wisdom” dispensed by John Q. Primary Care doctor.

Statins and the Cholesterol Hypothesis – Part I

Not a newly discovered article, rather one in my 'to be read' pile that I finally got to, but here it is in full (it was too hard to select just an exerpt). From Kurt G. Harris MD at his PāNu blog. There is a lot on his site I need to read.

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Statins and the Cholesterol Hypothesis – Part I


Wednesday, July 21, 2010 at 10:31AM

Reader Stephen is a young man I have corresponded with a few times on the subject of his diagnosis of FH (heterozygous Familial Hypercholesterolemia) and what he should do about it. His TC runs about 467 mg/dl and his LDL about 333 mg/dl. He has a CAC (calcium score) of 16, which is very high for a 24 year old man. This would be at about the 50th percentile for a 50 year old male on the SAD.

Stephen has of course given me permission to discuss his case here.

This is his most recent email to me:

Hi Dr. Harris,

It's been awhile since I last emailed you about any recent information regarding my heart scan. I also forgot to thank you for your last response and really appreciate the help you've given me. I recently had more lab work done and I am waiting to hear back for the results, although not much has changed since our last correspondence. However, now that I'm back in Dallas for my summer break I was able to get a proper heart scan at the Cooper Clinic. My CAC score was 16. I attended the Metabolism Society Symposium conference in Seattle a few months back and spoke with Jimmy Moore and a few others about my situation and they recommended I send Dr. Davis an email to get his advice on the matter. I recently heard back from him telling me basically that he strongly believes I go on statins while maintaining my current diet. Jimmy asked me to keep him posted about Dr. Davis' recommendations, so I emailed him, and he is now interested in posting a blog about it and asking others for suggestions since he is strongly against statin use. Anyways, I just wanted to update you, since you mentioned an interest in eventually making a post about this as well. If you're interested in having a look at the scan I can send another copy over to you as well as the results of the NMR profile I drew blood for a few days ago. If not, I completely understand as well, you have a lot on your plate as is. Let me know what you'd prefer and I'll do whatever works best for you. I look forward to hearing back from you.

Thanks again,

Stephen U.

By now you already know that I personally would avoid statins under any circumstances as they only work at all on heart attack risk via their effects on inflammation. Taking a sledgehammer to the entire cholesterol machinery has all kinds of negative knock-on effects, including promotion of cancer and interference with muscle and liver function, in addition to the accidental side benefit of reducing inflammation. It’s a crude approach, it has side effects that make all cause mortality over long periods of time likely to be worse, and the only group with any demonstrated benefit is men with established disease. The vast majority of those taking statins have no scientific basis for taking them. The rest, including those who have had an MI already, could likely accomplish far greater improvements in health with non-drug dietary measures like improved glucoregulatory control, and avoidance of the Neolithic agents of disease.

Let me summarize what we know about statins

1) A few older trials show an all-cause mortality benefit to statins in secondary prevention IN MEN (not women). The relative risk reduction is at most about 30% and the maximum absolute risk reduction is about 1% per year. (This means you still have about 70% of the relative risk of dying you had before the drug. Is it possible dietary changes could decrease your risk more substantially? I think so.) Secondary prevention means you have already had a heart attack or been proven to have coronary artery disease (CAD). If you only have high TC or LDL, this does not include you, and this does not include the majority of those now taking statins.

2) Other trials, especially more recent ones, are less likely to show a benefit, even in secondary prevention

3) For primary prevention, there is no demonstrated mortality benefit to taking statins.

4) When there are decreased deaths from cardiac events in primary prevention, there are more deaths by other causes. You may well be trading your heart attack for cancer. Because of the long lead time for cancer deaths, there are good theoretical reasons to believe that over periods of time - much longer than a few years (the length of the typical drug trial) all cause mortality could easily be higher when taking a statin for primary prevention.

5) When statins do work, they work by accident via their effects on inflammation. The side effects may be related to the lowering of LDL, but the benefits are not. Trials have failed to show the linear relationship between LDL lowering and cardiac end-points that one would expect if the effect were due to the LDL level.

I do not believe in any of the versions of the lipid hypothesis, ranging from Ancel Keys' original idea that cholesterol or dietary fat clogs the arteries, to the currently fashionable one that “small, dense” LDL particles are like microscopic rodents that are designed to burrow under the intima of your blood vessels and kill you.

Neither cholesterol nor any of the lipoproteins nor LP(a) is a "cause" of CAD (coronary artery disease). There is no evidence that “fixing” these numbers is of benefit other than by accident and there is plenty of evidence that you can kill people by trying to do so.

HDL, particle numbers, particle sizes, LP(a) are all parameters that are more or less associated with CAD. If they respond positively to changes in diet, then they are just covariant with decreased risk of CAD or MI due to the changes you made in your diet. They are not necessarily, and not usually the direct mediators of the decreased risk.

They may track the positive changes you make in your diet, but they are not causing heart attacks any more than shoe size causes height!

You cannot decrease your stature by amputating your toes. Believing any of the lipid hypotheses or the cholesterol hypothesis is the intellectual equivalent of amputating toes to decrease height because shoe size causes stature.

Correlation is not causation. Causation can cause a correlation to occur, but proof of correlation is not sufficient to prove causation. None of the lipid hypotheses are biologically plausible, and all have failed to be proven despite decades of research and billions in expenditure.

Say you observe that the neighborhoods that have the most numbers of police on patrol have more crime. A neighborhood in downtown Milwaukee has more than 8 times the per capita police presence than in Sturgeon Bay 120 miles to the north. The crime rate in downtown Milwaukee is also more than an order of magnitude higher. Say the calculated correlation coefficient is .85 – with 0 being no correlation and 1.0 perfect correlation. Is it reasonable to propose we reduce the number of police in Milwaukee in order to effect a lower crime rate? There is a very high (and statistically significant) correlation, but if we think of mechanisms, and how police presence relates to crime, we would probably think that the police are there in response to the crime and are not likely causing it. We might go a step further and say that it might be dangerous to reduce the number of police, as for all we know the city has put them there for good reason, and the crime differential between our two towns might become even greater without them.

In the same way, although high HDL indeed correlates with lower risk of MI (heart attack or myocardial infarction) and CAD (coronary artery disease), when we understand the biology of HDL production, we might be wary of approaches that attempt to increase HDL as if HDL is the agent protecting your heart. It might well matter how we alter HDL. It might be that HDL is high in response to whatever lowers heart attack risk.

It might be (In fact I think it is) that a diet high in saturated fat protects against atherosclerosis and also affects the numerical value of HDL (most of you know it does because you see it happen to you), such that the association of HDL and lower MI risk is because they are caused by the same thing (diet) instead of because one “causes” the other.

Consider the particle du jour of LP(a). Measured Lipoprotein (a) has a correlation with MI risk. It’s not really that high as a risk factor (not even remotely close to glycated hemoglobin or calcium score), but there is a positive correlation. In an individual human, Lipoprotein (a) could be high as an adaptive response to having lots of oxidized LDL and thereby may indicate you have an atherogenic diet, like the crime ridden neighborhood that has a substantial police presence. Or you could be just born with high levels of LP (a). In the same way a somewhat paranoid and wealthy community has lots of policemen on patrol even though the crime rate is low, you might have patrol cars of LP (a) cruising around even though you do not have intimal damage occurring.

Sidenote: I admit I have a bias towards this interpretation. My Lp(a) level is 85 yet my CIMT* measurement would be normal for someone 15 years younger and my CAC score is zero. Lp(a) levels can be highly heritable, and longevity and freedom from atherosclerosis runs in my family. As Peter would say, some of us may just be born with more sticking plasters, and some of us make more sticking plasters because we have more damage. It should be noted that the best way to decrease LP (a) is increasing saturated fat intake, but also that although there is positive correlation of LP(a) with disease on a population level, there is not yet a shred of evidence that any intervention to modify your LP(a) level modifies your risk.

The point is that just by observing more police patrols or more Lp(a), even in the context of a true correlation between crime and police and Lp(a) and MI, you cannot necessarily tell why the police are there or why the Lp(a) is elevated. More importantly, the idea that reducing the number of police will reduce crime or that pharmacologically altering Lp(a) will reduce risk may be not only false, but dangerously false. Some neighborhoods need their police, and some humans may need their Lp(a), just like some humans may have more heart attacks when we “help” them by pharmacologically jacking up their HDL.

This is in fact precisely the story of torcetrapib. This drug cost Pfizer over 800 million dollars to develop. Torcetrapib is an inhibitor of CETP - cholesterol ester transfer protein. CETP facilitates the transfer of cholesterol from HLD to VLDL or LDL. Now, if you believe version 3.0 of the lipid hypothesis, there are these things called “good” and “bad” cholesterol. This is cardiologist shorthand for lipoprotein-cholesterol complexes that cause or prevent heart disease. HDL is the good one and we want it to be high, so it can hoover up the cholesterol from arterial plaque (a ridiculous idea that as Malcolm Kendrick pointed out defies physical chemistry – Ornish’s “garbage trucks”) and shrink them. LDL is the bad one and we want it to be low, as it is constantly fighting to transport cholesterol to the arterial plaque.

Cardiologists and Pfizer actually believe that LDL is trying to kill you and HDL is trying to save you at the same time. They figured, why not throw our pharmacological weight into the fight? If we inhibit CETP, the level of HDL will rise, and the level of LDL will fall. They actually combined torcetrapib with an extant statin (atorvastatin or Lipitor) to really, really get the LDL down as well as the HDL up.

So how did it work? Well, it worked spectacularly. HDL levels soared and LDL levels went down. I mean, we are talking HDL to LDL ratios that epidemiologists and cardiologists would say should reduce the risk of heart attack to zero. There was a glitch, though. Although the HDL and LDL went exactly the way they wanted, the risk of death in the group that got the torcetrapib was 60% higher. The trial was halted early.

Sidenote: We could belabor the police metaphor by saying pharmacologic elevation of HDL with torcetrapib was a bit like recruiting Alex’s droogs into the police in “Clockwork Orange”. The crime rate would go up with more police recruited from among those who are themselves criminals.

So do you think it is plausible that LDL causes heart disease and HDL saves us from it? Or is it more likely that these laboratory numbers are merely epiphenomena to the real primary process?

Is it really plausible that our bodies evolved to simultaneously create two substances that are like some perverse yin and yang, with good HDL trying to save us from the LDL that is furiously trying to clog our arteries with cholesterol?

Or is this all a bunch of biologically implausible nonsense?

Taking all the evidence in its totality, I’ve see no compelling use for statins for anyone if they have truly optimized their diet, and very little even if they haven’t. The benefits of statins are unrelated to their effects on “cholesterol” or lipoprotein levels, are small and are accidental.

The risk/benefit ratio and effect size of dietary modifications are likely to be superior to any of the current statin drugs.

I do believe there are dietary ways that we can minimize the risk of atherosclerosis and other inflammatory processes, minimize the risk of acute plaque rupture and thrombosis if we do have atherosclerosis, and minimize the risk of a fatal arrhythmia if these upstream steps fail

I don’t believe once you have taken these steps, that pharmacology targeted to “cholesterol” or lipoproteins has anything to add.

I suggest:

1) Avoidance of excess PUFA in the diet that leads to oxidized LDL and possible endothelial damage
2) Avoidance of all the causes of leaky gut that may lead to the suite of inflammatory processes known as the metabolic syndrome – avoid excess PUFA (esp. linoleic acid), wheat, and fructose
3) Plenty of saturated fat intake
4) If your glucoregulation is impaired, reduce carbohydrate consumption to whatever is necessary to minimize glycation and endothelial damage. Minimize glycated hemoglobin (Hemoglobin A1c) to the degree possible
5) Replacement of essential micronutrients that may be deficient on the SAD. Magnesium, sunshine, pastured butter for Vit K2.

Those are my general recommendations for everyone.

So what if you have FH? Are the recommendations different?

More discussion in the next post.

*CIMT is carotid intima/media thickness - easily measured noninvasively with ultrasound and a more sensitive measure of early atherosclerosis than CAC (calcium score) in men under 40 and women under 50