The anti-coronary club. A dietary approach to the prevention of coronary heart disease--a seven-year report

Dietary Transitions and Health Outcomes in Four Populations - Systematic Review

IMPORTANCE

Non-communicable chronic diseases (NCDs) such as obesity, type 2 diabetes, heart disease, and cancer were rare among non-western populations with traditional diets and lifestyles. As populations transitioned toward industrialized diets and lifestyles, NCDs developed.

OBJECTIVE

We performed a systematic literature review to examine the effects of diet and lifestyle transitions on NCDs.

EVIDENCE REVIEW

We identified 22 populations that underwent a nutrition transition, eleven of which had sufficient data. Of these, we chose four populations with diverse geographies, diets and lifestyles who underwent a dietary and lifestyle transition and explored the relationship between dietary changes and health outcomes. We excluded populations with features overlapping with selected populations or with complicating factors such as inadequate data, subgroups, and different study methodologies over different periods. The selected populations were Yemenite Jews, Tokelauans, Tanushimaru Japanese, and Maasai. We also review transition data from seven excluded populations (Pima, Navajo, Aboriginal Australians, South African Natal Indians and Zulu speakers, Inuit, and Hadza) to assess for bias.

FINDINGS

The three groups that replaced saturated fats (SFA) from animal (Yemenite Jews, Maasai) or plants (Tokelau) with refined carbohydrates had negative health outcomes (e.g., increased obesity, diabetes, heart disease). Yemenites reduced SFA consumption by >40% post-transition but men's BMI increased 19% and diabetes increased ~40-fold. Tokelauans reduced fat, dramatically reduced SFA, and increased sugar intake: obesity and diabetes rose. The Tanushimaruans transitioned to more fats and less carbohydrates and used more anti-hypertensive medications; stroke and breast cancer declined while heart disease was stable. The Maasai transitioned to lower fat, SFA and higher carbohydrates and had increased BMI and diabetes. Similar patterns were observed in the seven other populations.

CONCLUSION

The nutrient category most strongly associated with negative health outcomes - especially obesity and diabetes - was sugar (increased 600-650% in Yemenite Jews and Tokelauans) and refined carbohydrates (among Maasai, total carbohydrates increased 39% in men and 362% in women), while increased calories was less strongly associated with these disorders. Across 11 populations, NCDs were associated with increased refined carbohydrates more than increased calories, reduced activity or other factors, but cannot be attributed to SFA or total fat consumption.

United States Dietary Trends Since 1800: Lack of Association Between Saturated Fatty Acid Consumption and Non-communicable Diseases

We reviewed data on the American diet from 1800 to 2019. Methods: We examined food availability and estimated consumption data from 1800 to 2019 using historical sources from the federal government and additional public data sources. Results: Processed and ultra-processed foods increased from <5 to >60% of foods. Large increases occurred for sugar, white and whole wheat flour, rice, poultry, eggs, vegetable oils, dairy products, and fresh vegetables. Saturated fats from animal sources declined while polyunsaturated fats from vegetable oils rose. Non-communicable diseases (NCDs) rose over the twentieth century in parallel with increased consumption of processed foods, including sugar, refined flour and rice, and vegetable oils. Saturated fats from animal sources were inversely correlated with the prevalence of NCDs. Conclusions: As observed from the food availability data, processed and ultra-processed foods dramatically increased over the past two centuries, especially sugar, white flour, white rice, vegetable oils, and ready-to-eat meals. These changes paralleled the rising incidence of NCDs, while animal fat consumption was inversely correlated.

The Origins and Early Evolution of Epidemiologic Research in Cardiovascular Diseases: A Tabular Record of Cohort and Case-Control Studies and Preventive Trials Initiated From 1946 to 1976

This article serves as a ready reference guide to the pioneering formal studies in cardiovascular disease (CVD) epidemiology initiated during 3 decades of the subject's evolution into an established academic field that contributed to the public health. The article is not intended to be a history of CVD epidemiology or an editorial about its significance. The appended tables include the titles and starting dates of the early studies, the names of their principal investigators, and references to a single defining article from each. The early observational studies of CVD epidemiology provided a widely useful CVD risk-factor paradigm. The early clinical trials justified the more definitive preventive trials of the 1980s and beyond. This early research in populations, along with others in clinics and laboratories, led to greater understanding of the causes of CVD, to a vigorous practice of preventive cardiology, and to national policy and programs of health promotion, all of which were coincident with a 50-year decline in CVD mortality rates.

Cholesterol Lowering Guidelines: From Whence We Came and Where We Are Now

Treatment guidelines have proliferated in cardiology, although most guideline recommendations are not supported by clinical trial evidence. What is considered to be a normal cholesterol level has progressively declined over the past 50 years, with the increasing realization that "normal" is far from optimal and that lower is better. The first important United States and Canadian cholesterol guidelines were published in 1988, and recommended diet for 6 months to be followed by consideration of bile acid sequestrants or nicotinic acid. Over the ensuing 25 years guidelines have changed rapidly and dramatically in response to a large number of definitive clinical trials, usually with statins. Low-density lipoprotein cholesterol targets have moved progressively lower, and in some guidelines, have been abandoned entirely. The concept of selecting patients for treatment according to the absolute risk reduction expected from treatment on the basis of clinical trial data seems to be a rational approach. For secondary prevention, some patients are still untreated or undertreated, presenting an opportunity for improving outcomes.

A network analysis of the propagation of evidence regarding the effectiveness of fat-controlled diets in the secondary prevention of coronary heart disease (CHD): Selective citation in reviews

OBJECTIVE

To examine how the first randomised controlled trials (RCTs) evaluating the efficacy of cholesterol-lowering diets in the secondary prevention of coronary heart disease were interpreted in reviews of the literature prior to the National Institutes of Health consensus conference in 1984.

DESIGN

Claim-specific citation network analysis was used to study the network of citations between reviews and RCTs over a defined period (1969-1984). RCTs were identified and classified according to whether their conclusions supported or opposed the use of dietary fat modification/restriction in the secondary prevention of coronary heart disease. Each review published in this period that cited any of the RCTs was classified as supportive, neutral, or unsupportive to the use of dietary fat modification based on a quotation analysis of its evaluation of the findings of these RCTs. Citation bias and underutilisation were detected by applying a comparative density measure, in-degree centrality, and out-degree in a series of sub-graph analyses.

RESULTS

In total, 66 unique publications were identified (four RCTs-one supportive, three unsupportive; 62 reviews-28 supportive, 17 neutral, 17 unsupportive). On average, supportive reviews underutilised the available RCTs to a greater degree than other reviews. Amongst the supportive group, citation bias was common-23 (82%) reviews cited only the one RCT that was supportive.

CONCLUSION

Most reviews that disseminated a supportive evaluation of the results of RCTs in the context of secondary prevention cited only data that supported this position.

Thematic review series: The Pathogenesis of Atherosclerosis. An interpretive history of the cholesterol controversy: part II:the early evidence linking hypercholesterolemia to coronary disease in humans

The first in this series of historical reviews dealt with the pioneering animal model work of Anitschkow, implicating blood cholesterol in the pathogenesis of atherosclerosis, and the pivotally important work of Gofman, providing evidence that lipoprotein-bound cholesterol was a major factor in the human disease. This second installment reviews the early lines of evidence linking hypercholesterolemia in humans to the progression of atherosclerosis and the risk of coronary heart disease. The argument is made that by 1970, the evidence was already strong enough to justify intervention to lower blood cholesterol levels if all the available lines of evidence had been taken into account. Yet, it would be almost two decades before lowering blood cholesterol levels became a national public health goal. Some of the reasons the "cholesterol controversy" continued in the face of powerful evidence supporting intervention are discussed.

Lipoproteins, nutrition, and heart disease

This article reviews the current status of our knowledge of lipoproteins, nutrition, and coronary heart disease (CHD). Special emphasis is placed on CHD risk assessment, dietary intervention studies, diet-gene interactions, and current dietary guidelines and the contributions of my laboratory to these areas. CHD remains a major cause of death and disability, and risk factors include age, sex, hypertension, smoking, diabetes, elevated serum LDL cholesterol, and low HDL cholesterol. Emerging independent risk factors include elevated serum concentrations of lipoprotein(a), remnant lipoproteins, and homocysteine. The cornerstone of CHD prevention is lifestyle modification. Dietary intervention studies support the concepts that restricting saturated fat and cholesterol and increasing the intake of essential fatty acids, especially n - 3 fatty acids, reduces CHD risk. The variability in LDL-cholesterol response to diet is large, related in part to APOE and APOA4 genotype. The use of antioxidants in intervention studies has not been shown to reduce CHD risk. Compliance with dietary recommendations remains a major problem, and directly altering the food supply may be the most effective way to ensure compliance. The available data indicate that the recommendation to use fats, oils, and sugars sparingly for CHD prevention should be modified to a recommendation to use animal, dairy, and hydrogenated fats; tropical oils; egg yolks; and sugars sparingly and to increase the use of vegetables, fruit, and whole grains.

Diet and coronary heart disease: clinical trials

Dietary intervention trials using coronary heart disease (CHD) mortality and morbidity as endpoints have demonstrated that restriction of dietary total and saturated fat or replacement of the latter with polyunsaturated fatty acids (PUFAs), in particular n-3 PUFAs, is of great benefit with respect to CHD risk. This is likewise the case for intervention trials using angiographic endpoints, with many studies showing that such diets not only retard progression of coronary atherosclerosis but can cause regression as well. The role that antioxidants, such as vitamin E, may play in the development and progression of CHD is less clear. The results of large-scale clinical trials evaluating the effect of vitamin E supplementation on CHD risk do not support the concept that this agent is cardioprotective. The purpose of this report is to review dietary intervention trials that support a direct relationship between diet, lipoproteins, and CHD risk.

Dose-dependent effect of hydroxymethylglutaryl-coenzyme A reductase inhibitor on serum cholesterol with limited dietary restrictions: a case study

Hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor (pravastatin sodium) can selectively inhibit cholesterol biosynthesis in the liver and may lower serum cholesterol concentrations even where there are no particular dietary restrictions. A 72-year old housewife with non-insulin-dependent diabetes mellitus complicated by hyperlipaemia type IIb, who did not follow directions for diet therapy or kinesitherapy, was administered HMG-CoA reductase inhibitor. The initial dose of 10 mg/day HMG-CoA reductase inhibitor was increased by 10 mg/day every 4 weeks to 30 mg/day, maintained at 30 mg/day for 8 weeks and then reduced gradually until discontinuation after a further 27 weeks. Test results showed the changes in low-density lipoprotein cholesterol and apoprotein B to be dose-dependent. The findings represent the first clinical evidence that hypercholesterolaemia can be adequately managed by the use of HMG-CoA reductase inhibitor, even when no specific dietary restrictions are imposed, and may contribute to improvements in the quality of daily life for many patients suffering from hyperlipaemia type IIb.

Influence of dietary fat, apolipoprotein E phenotype, and sex on plasma lipoprotein levels

BACKGROUND

The "Western" diet, sex, and apolipoprotein (Apo) E polymorphism have been implicated as codeterminants of lipid levels.

METHODS AND RESULTS

In a retrospective analysis, we evaluated the combined impact of dietary fat, sex, and Apo E phenotype on lipoprotein levels in 67 subjects fed two contrasting, metabolically controlled diets: one a "Western" diet, with a low polyunsaturated to saturated (P:S) fatty acid ratio and the other a "therapeutic" diet, with a high P:S ratio. The high P:S diet compared with P:S diet exerted a far stronger predictive influence on lipoprotein concentrations than Apo E phenotype, sex, or the latter two factors combined. Apo E phenotype alone was associated with a stepwise increase in low density lipoprotein cholesterol (LDL-C), such that 3/2 less than 3/3 less than 4/3 on either the low or the high P:S diets. On the low P:S diet only, sex was shown to be a significant predictor of high density lipoprotein cholesterol (HDL-C) levels, with women greater than men, and the associated LDL/HDL ratio with men greater than women. On the high P:S diet, women displayed a dramatic fall in HDL-C, effectively raising the LDL/HDL ratio to equivalency with men and obliterating the sex influence seen with the low P:S diet. Controlled for dietary fat, Apo E and sex exerted independent, additive effects on lipoprotein levels on the low P:S diet only. Only the Apo E phenotype remained predictive on the high P:S diet.

CONCLUSIONS

Women of the Apo E 3/2 phenotype stand to benefit the least from a high P:S diet because of reduction in the more "protective" HDL-C, whereas men of the 4/3 phenotype showed the greatest improvement in the LDL/HDL ratio.

Dietary polyunsaturated fats of the W-6 and W-3 series reduce postprandial lipoprotein levels. Chronic and acute effects of fat saturation on postprandial lipoprotein metabolism

The chronic and acute effects of different types of dietary fat on postprandial lipoprotein metabolism were studied in eight normolipidemic subjects. Each person was placed for 25 d on each of three isocaloric diets: a saturated fat (SFA), a w-6 polyunsaturated fat (w-6 PUFA) and a w-3 polyunsaturated fat (w-3 PUFA) diet. Two vitamin A-fat loading tests were done on each diet. The concentrations in total plasma and chylomicron (Sf greater than 1,000) and nonchylomicron (Sf less than 1,000) fractions of retinyl palmitate (RP) were measured for 12 h postprandially. Compared with the SFA diet, the w-6 PUFA diet reduced chylomicron and nonchylomicron RP levels 56 and 38%, respectively, and the w-3 PUFA diet reduced these levels 67 and 53%, respectively. On further analysis, the main determinant of postprandial lipoprotein levels was the type of fat that was chronically fed, which appeared to mediate its effect by changing the concentration of the endogenous competitor for the system that catabolizes triglyeride-rich lipoproteins. However, there was a significant effect of the acute dietary fat load, which appeared to be due to a differential susceptibility to lipolysis of chylomicrons produced by SFA as opposed to PUFA fat loads. The levels of postprandial lipoproteins are determined by the interaction of these chronic and acute effects.

Intervention for the prevention and control of hypertension and atherosclerotic diseases: United States and international experience

Intervention to control hypertension and prevent coronary heart disease was initially undertaken in the United States in the late 1950s. It was conducted along three lines: randomized controlled trials, community demonstration projects, and broad public health and medical care efforts involving both the general population and its high-risk strata. This article reviews findings from the United States trials, particularly those on the primary prevention of coronary heart disease by unifactorial means (such as fat-modified diet, serum cholesterol-lowering drugs, antihypertensive drug treatment) and by multifactorial interventions. Results of unifactorial and multifactorial trials are discussed with reference to the prevention of high blood pressure. Studies in the United States are compared with research abroad, and current research needs are reviewed together with the implications for medical practice and public health. The United States population as a whole has a large high-risk segment. Since the late 1950s, significant population-wide changes have occurred in life-styles (diet, smoking, exercise habits), and this is especially true of the more educated. The proportion of persons with detected, treated, and controlled high blood pressure has risen markedly in all population strata. Consequently, a favorable shift has occurred in the population distribution of the major established risk factors: "rich" diet, hypercholesterolemia, high blood pressure, and cigarette smoking. It can be reasonably inferred that the steady and marked declines in death rates in the United States from coronary heart disease, stroke, all cardiovascular diseases, and all causes since 1968 are related to reductions in these risk factors.

Epidemiology of coronary heart disease: the Framingham study

Coronary heart disease continues to be the number one cause of death in most Northern European, North American and other industrialized Caucasian societies. By the age of 60, every fifth man and one in 17 women have some form of this disease. One in 15 men and women will eventually have a stroke. Other cardiovascular diseases related to atherosclerosis are also important. Epidemiologic (prospective) studies enable one to predict most of the potential victims of cardiovascular disease, years before they become ill. An increase in total to high-density lipoprotein cholesterol ratio, hypertension, cigarette smoking, excess weight, elevated blood sugar levels, lack of exercise, stress, electrocardiographic abnormalities, and other factors are associated with the development of these diseases. Intervention trials have generally shown that lowering "risk factors" reduces the subsequent rate of coronary heart disease, stroke, and other cardiovascular disease. Most highly susceptible subjects have problems with several risk factors. Management of one should not interfere with management of another if optimal health is sought.

Effects of a low cholesterol eating plan on plasma lipids: results of a three-year community study

In an attempt to demonstrate whether individuals with average plasma lipids would accept a diet low in saturated fat and cholesterol, members of a community organization were taught the HELP Your Heart Eating Plan. Results of 282 individuals suggest that reduced dietary cholesterol from selected foods could be sustained for up to 36 months. While both plasma cholesterol and triglycerides fell during a year of instruction, both rose to above initial values by 36 months. Overall, the results suggest that adults may be willing to accept a new style of eating temporarily but are not committed to making permanent dietary changes.

George Lyman Duff Memorial Lecture. Lifestyles, major risk factors, proof and public policy

In this report major risk factors in coronary heart disease (CHD) are reviewed, with particular emphasis on the role of nutrition. International and national epidemiologic data indicate that reducing or eliminating certain risk factors (e.g., a diet high in cholesterol and saturated fats) may reduce the risk of premature CHD. Most trends indicate that many Americans are more concerned about diet for health reasons. Preventive measures for CHD are also discussed.

The Erysichthon syndrome. Progression of coronary atherosclerosis and dietary hyperlipidemia

One hundred nineteen patients with coronary artery disease confirmed by coronary arteriograms were studied. Cine coronary arteriography confirmed progression of atherosclerosis in 106 (89%) patients (mean age 50.9 yr) and nonprogression in 13 (11%) patients (mean age 50.3 yr). Progression was defined as follows: any increase to 50% stenosis, 50% to 75% narrowing, 75% to 90%, 90% to 99%, 99% to total occlusion. Only one patient of the 106 who progressed (less than 1%) had ideal values for both cholesterol and triglyceride. Three of 13 patients (23%) who did not progress had ideal lipid values (P less than 0.005). Fifty four of 106 patients who progressed had cholesterol levels greater than or equal to 250 mg%; none of 13 patients who did not progress had such levels (P less than 0.005). Thirty-nine of 98 (40%) patients who progressed had hypertension; only one (8%) who did not progress had hypertension (P less than 0.025). Seventy-four of 96 patients who progressed were smokers (77%); two of 13 nonprogression patients smoked (15%) (P less than 0.005).

Cost/benefit analysis of treatment and prevention of myocardial infarction

The benefits resulting from introduction of coronary care units, mobile coronary care units, and a screening and intervention program to decrease the incidence of myocardial infarction (MI) are reduced to a common basis by modeling the effects of the three strategies as applied to a cohort of 10-years-olds. Published data on MI are used with a semi-Markov model of death from MI and other causes to estimate program effects on long-term survival, and cost/benefit ratios are compared for the three programs with both costs and benefits discounted over the lifetime of the cohort. Some problems of selecting a discount rate for comparing programs that incur costs and accrue benefits at widely separated times are discussed.

Diet and atherosclerosis

Because of the statistical establishment of elevated blood lipids as a risk factor in the development of atherosclerotic heart disease, most of the attempts to regulate blood lipids by diet are centered on the fat in the diet. The levels of blood lipids and the course of experimental atherosclerosis can be affected by other dietary components such as type and amount of protein, carbohydrate, and nonnutritive fiber. Interaction among the dietary components further affects serum lipids and atherosclerosis.

Primary and secondary prevention trials in coronary heart disease

Trials in primary and secondary prevention of coronary heart disease (CHD) are reviewed. The results of completed primary prevention trials suggest that dietary changes in middle-aged men may lower the incidence of CHD. Multifactorial trials may achieve an even greater reduction in CHD. Secondary prevention trials indicate that stopping smoking and the use of beta-blocking agents are effective in reducing recurrence rates.

Behavioral science applied to cardiovascular health: progress and research needs in the modification of risk-taking habits in adult populations

Epidemiological and experimental studies provide evidence that a complex of behavioral, biological and environmental factors interact in the etiology of many cardiovascular diseases. A survey of research and theory concerning training and counseling programs for adult populations is provided. Six basic behavioral recommendations are made for the maintenance of cardiovascular health. Problems in the design of mass media and interpersonal campaigns to alter the health habits of large populations are considered.

The cardiologist's responsibility for preventing coronary heart disease

The recent increase in coronary heart disease is real and the causes must mainly be environmental. Consequently the condition should largely be preventable. The application of what is already known is likely to be a far more effective way of reducing the mortality rate than all attempts at palliative treatment, but vigorous action will be necessary. Much greater sums are being expended on coronary-care units and cardiac surgery than in preventing the need for them, although there is little evidence that they have significantly lowered the over-all mortality rate. Conventional treatment is immensely expensive. Prevention could in the long run be much cheaper. Cardiologists on their own are unlikely to succeed in a program of prevention. They need the help of many others, including community nurses, nutritionists, public health workers, sociologists, and of course general practitioners, but they have responsibility for leadership and for providing background knowledge. For the detection of certain risk factors, health examinations are necessary and should be part of general practice. Also, advice is best given on an individual basis. The chief-known risk factors (hyperlipidemia, hypertension, smoking, physical inactivity) could be controlled. CHD occurs in adults but atherosclerosis starts many years before. Prevention should begin with appropriate infant feeding, whenever possible with breast milk, and continue into childhood, when habits are formed and attitudes to life can best be influenced. It should be possible to bring up children virtually free from risk factors. It may never be possible to prove the effectiveness of such a multifactorial program by prospective controlled intervention studies, but the evidence indicates strong probability. The stakes are too high to delay action any longer. Physicians daily give advice in areas where the evidence is much less certain. Such a program for the control of coronary artery disease is urgently needed and could become one of the most rewarding activities for the medical profession.

Classification of lipoproteins and lipoprotein disorders

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