Causes of heart disease (original) (raw)

The Questionable Role of Saturated and Polyunsaturated Fatty Acids in Cardiovascular Disease

Journal of Clinical Epidemiology, 1998

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

Nutritional mechanisms that influence cardiovascular disease

The American Journal of Clinical Nutrition, 2006

Current evidence suggests that most significant risk factors for heart disease have been identified. Although age, sex, and genetics are important unmodifiable risk factors, most new cases of acute myocardial infarctions today can be predicted by the presence and level of 9 risk (or cardioprotective) factors that can easily be assessed and, most importantly, modified. These risk factors are the same in almost every geographic region and in every racial/ethnic group worldwide and are consistent in men and women. Eight of these 9 risk factors are influenced by diet, and most act by promoting atherogenesis, which is the most important background condition for cardiovascular disease. Dietary interventions mostly affect atherogenesis by modulating, at the cellular level, proinflammatory processes that initiate and perpetuate endothelial dysfunction, plaque formation, and, eventually, plaque rupture. For example, there is now enough evidence, both epidemiologic and clinical, of the beneficial effects of nҀ3 fatty acids. Either as part of a normal low-fat diet or as supplements, these fatty acids are now recommended to prevent cardiovascular disease. This review will summarize the mechanisms by which diet may influence atherogenesis through the early inception, progression, and clinical emergence of atherosclerosis, with a special focus on nҀ3 fatty acids.

Saturated Fat and Cardiovascular Disease

This article highlights the relationship between saturated fat intake and its association with cardiovascular diseases through available literature. Saturated fat intake has been believed to be one of the causable factors of cardiovascular disease due its association with the increase level of the blood cholesterol and other lipoproteins. But available case control studies, systematic reviews and Meta-analysis of prospective cohort studies, and randomised trail studies are still not sufficient to provide strong evidence on direct relationship of saturated fat intake and cardiovascular disease and death rate. The lack of strong association and fully depicted mechanism of the cholesterol and lipoprotein such LDL, total to HDL cholesterol to cause cardiovascular disease still generate uncertainty to support recommendation of reduction of dietary saturated fat has beneficial effect on prevention and reduction of cardiovascular disease risk

Saturated fat, carbohydrates and cardiovascular disease

The Netherlands journal of medicine, 2011

The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in observational cohorts, while replacing SAFA with polyunsaturated fatty acids (PUFA) is associated with reduced CVD risk. However, replacing a combination of SAFA and trans-fatty acids with n-6 PUFA (notably linoleic acid) in controlled trials showed no indication of benefit and a signal toward increased coronary heart disease risk, suggesting that n-3 PUFA may be responsible for the protective association between total PUFA and CVD. High CHO intakes stimulate hepatic SAFA synthesis and conservation of dietary SAFA . Hepatic de novo lipogenesis from CHO is also stimulated during eucaloric dietary substitution of SAFA by CHO with high glycaemic index in normo-insulinaemic subjects and during h...

Fatty acids linked to cardiovascular mortality are associated with risk factors

International journal of circumpolar health, 2015

Although saturated fatty acids (FAs) have been linked to cardiovascular mortality, it is not clear whether this outcome is attributable solely to their effects on low-density lipoprotein cholesterol (LDL-C) or whether other risk factors are also associated with FAs. The Western Alaskan Native population, with its rapidly changing lifestyles, shift in diet from unsaturated to saturated fatty acids and dramatic increase in cardiovascular disease (CVD), presents an opportunity to elucidate any associations between specific FAs and known CVD risk factors. We tested the hypothesis that the specific FAs previously identified as related to CVD mortality are also associated with individual CVD risk factors. In this community-based, cross-sectional study, relative proportions of FAs in plasma and red blood cell membranes were compared with CVD risk factors in a sample of 758 men and women aged ≥35 years. Linear regression analyses were used to analyze relations between specific FAs and CVD r...

Dietary fatty acids and cardiovascular disease: An epidemiological approach

Progress in Lipid Research, 2008

The quality of dietary fat in relation to cardiovascular disease forms the basis of the diet-heart hypothesis. Current recommendations on dietary fat now emphasise quality rather than quantity. The focus of this review is to summarise the results from prospective cohort studies on dietary fat and cardiovascular disease outcomes. Relatively few prospective cohort studies have found an association between dietary fat quality and cardiovascular disease, partly because of limitations in estimating dietary intake. Saturated and trans fatty acids have increased cardiovascular risk in several studies. Both nÀ6 and nÀ3 polyunsaturated fatty acids have been associated with lower cardiovascular risk. Within the nÀ6 series, linoleic acid seems to decrease cardiovascular risk. Within the nÀ3 series the long-chain fatty acids (eicosapentaenoic and docosahexaenoic acids) are associated with decreased risk for especially fatal coronary outcomes, whereas the role of a-linolenic acid is less clear. Dietary fat quality also influences the activity of enzymes involved in the desaturation of fatty acids in the body. Serum desaturase indices have been consistently associated with adverse cardiovascular outcomes. Data from metabolic and clinical studies reinforce findings from observational studies supporting recommendations to replace saturated and trans fat with unsaturated fat in the prevention of cardiovascular disease.

Saturated fatty acids and coronary heart disease risk: the debate goes on

Current opinion in clinical nutrition and metabolic care, 2015

Recently published meta-analyses of cohort studies and randomized controlled trials (RCTs) have challenged the link between saturated fatty acid (SFA) intake and coronary heart disease (CHD) risk. This review considers the outcome of these studies in the context of other evidence. Recent meta-analyses of cohort studies suggest that reducing SFA intakes has little impact on CHD risk when replaced by carbohydrates. The evidence for benefits on CHD risk of replacing SFA with unsaturated fatty acids in cohort studies is stronger and is also supported by data from a recent Cochrane analysis of RCTs of dietary SFA reduction and CHD risk. This review highlights the challenges of cohort studies involving diet because of the changing patterns of dietary behaviour and other multifactorial risk factors. The studies included are normally conducted over many years and are often dependent on a single measurement of dietary intake. The link between SFA intake, plasma cholesterol, and CHD risk is b...