Implausible discussions in saturated fat ‘research’; definitive solutions won’t come from another million editorials (or a million views of one) (original) (raw)
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Systematic Reviews
Background The health effects of dietary fats are a controversial issue on which experts and authoritative organizations have often disagreed. Care providers, guideline developers, policy-makers, and researchers use systematic reviews to advise patients and members of the public on optimal dietary habits, and to formulate public health recommendations and policies. Existing reviews, however, have serious limitations that impede optimal dietary fat recommendations, such as a lack of focus on outcomes important to people, substantial risk of bias (RoB) issues, ignoring absolute estimates of effects together with comprehensive assessments of the certainty of the estimates for all outcomes. Objective We therefore propose a methodologically innovative systematic review using direct and indirect evidence on diet and food-based fats (i.e., reduction or replacement of saturated fat with monounsaturated or polyunsaturated fat, or carbohydrates or protein) and the risk of important health out...
Restricting Saturated Fat May Not Be Required to Reduce Risk of Cardiovascular Disease
Topics in Clinical Nutrition, 2019
The purpose of this review was to determine whether the recommendation to reduce saturated fatty acid (SFA) consumption to treat or prevent cardiovascular disease (CVD) is relevant in the context of current peer-reviewed, evidence-based literature. A literature review regarding SFA and CVD was conducted using articles from 2011 to 2018 through PubMed. Three hundred seventy-four articles were found, of which 211 were excluded. The remainder included 37 primary research articles and 21 reviews. All of the publications were examined using the Evidence Analysis Library Quality Criteria. Existing evidence supporting a reduction in SFA to treat/prevent CVD is limited and conflicting.
Saturated fat –a never ending story?
Food & Nutrition Research
Science has no clear message regarding health effects of saturated fats, it seems. Different RCTs, prospective cohort studies and meta-analysis have led to contrasting conclusions. The aim of the present commentary is to discuss some possible reasons for an apparently never-ending fat controversy. They are of a purely scientific nature, which is important to recognize, but unfortunately hard to overcome. First is the placebo problem. In pharmaceutical science, evidence-based medicine is often synonymous with data on verified medical events from long-lasting double-blind randomized placebo controlled trials. In nutritional science the lack of double-blind design and lack of placebo food generate less conclusive data than those achieved in pharmaceutical science. Some scientists may apply the same type of scientific criteria used to evaluate the effects of drugs for foods. This leaves an impression of insufficient data since in this respect the fundamental criteria for evidence based medicine are not present. The next scientific problem is the energy balance equation. In contrast to pharmaceuticals, nutrients contain energy. An increased intake of one nutrient will lead to a decreased intake of another. The effect of change in only one nutrient is then difficult to isolate. Lastly, in nutritional science, generalizability is difficult compared to pharmaceutical science. Food culture interferes with lifestyle and food habits change over time. In conclusion, all available knowledge, from molecular experiments to population studies, must be taken in to account, to convert scientific data into dietary recommendations.
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...
American Journal of Clinical Nutrition, 2011
Current dietary recommendations advise reducing the intake of saturated fatty acids (SFAs) to reduce coronary heart disease (CHD) risk, but recent findings question the role of SFAs. This expert panel reviewed the evidence and reached the following conclusions: the evidence from epidemiologic, clinical, and mechanistic studies is consistent in finding that the risk of CHD is reduced when SFAs are replaced with polyunsaturated fatty acids (PUFAs). In populations who consume a Western diet, the replacement of 1% of energy from SFAs with PUFAs lowers LDL cholesterol and is likely to produce a reduction in CHD incidence of ≥2-3%. No clear benefit of substituting carbohydrates for SFAs has been shown, although there might be a benefit if the carbohydrate is unrefined and has a low glycemic index. Insufficient evidence exists to judge the effect on CHD risk of replacing SFAs with MUFAs. No clear association between SFA intake relative to refined carbohydrates and the risk of insulin resistance and diabetes has been shown. The effect of diet on a single biomarker is insufficient evidence to assess CHD risk. The combination of multiple biomarkers and the use of clinical endpoints could help substantiate the effects on CHD. Furthermore, the effect of particular foods on CHD cannot be predicted solely by their content of total SFAs because individual SFAs may have different cardiovascular effects and major SFA food sources contain other constituents that could influence CHD risk. Research is needed to clarify the role of SFAs compared with specific forms of carbohydrates in CHD risk and to compare specific foods with appropriate alternatives.
Dietary Saturated Fats and Health: Are the U.S. Guidelines Evidence-Based?
Nutrients
The last decade has seen nearly 20 papers reviewing the totality of the data on saturated fats and cardiovascular outcomes, which, altogether, have demonstrated a lack of rigorous evidence to support continued recommendations either to limit the consumption of saturated fatty acids or to replace them with polyunsaturated fatty acids. These papers were unfortunately not considered by the process leading to the most recent U.S. Dietary Guidelines for Americans, the country’s national nutrition policy, which recently reconfirmed its recommendation to limit saturated fats to 10% or less of total energy intake, based on insufficient and inconsistent evidence. Continuation of a cap on saturated fat intake also fails to consider the important effects of the food matrix and the overall dietary pattern in which saturated fatty acids are consumed.
Global Journal of Health Science, 2018
Background: Coronary heart disease (CHD) is a leading cause of death worldwide. Saturated fats were known as a risk factor for CHD and dietary guidelines restrict the daily consumption of SFs. However, the association between SFs and higher risk of CHD is not clear. This systematic review includes 14 high-quality prospective cohort studies which reported the association between CHD and SFs. Objective: This systematic review aims to examine the association between SFs intake and higher risk of CHD among prospective cohort studies. Design: A systematic review was conducted for published literaure in Scopus and ProQuest during the period 2000 to 2017. Studies included if they have a prospective cohort design with follow-up more than 4 years, published in English, and provide information about the association of interest. Data were extracted and summarised into three tables. Results: A total number of 14 prospective cohort studies were included in this review in which all from developed countries and half of them were from the USA. The total number of participants ranging from 501 to 344,696 in follow-up period from 4.8 to 30 years where 26,322 events of CHD and 629 CHD deaths were reported. The highest positive association HR (95%CI) was 5.17 (1.64-16.36) for CHD mortality and 1.36 (0.98-1.88) for CHD incidence. In contrast, the highest inverse association was found 0.73 (0.53-1.01) for CHD mortality and 0.62 (0.35-1.11) for CHD incidence. Conclusion: This systematic review suggests that SFs intake was not associated with higher incidence or mortality of CHD.
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
The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.
Journal of the American Heart Association, 2016
Background Saturated fat ( SFA ), ω‐6 (n‐6) polyunsaturated fat ( PUFA ), and trans fat ( TFA ) influence risk of coronary heart disease ( CHD ), but attributable CHD mortalities by country, age, sex, and time are unclear. Methods and Results National intakes of SFA , n‐6 PUFA , and TFA were estimated using a Bayesian hierarchical model based on country‐specific dietary surveys; food availability data; and, for TFA , industry reports on fats/oils and packaged foods. Etiologic effects of dietary fats on CHD mortality were derived from meta‐analyses of prospective cohorts and CHD mortality rates from the 2010 Global Burden of Diseases study. Absolute and proportional attributable CHD mortality were computed using a comparative risk assessment framework. In 2010, nonoptimal intakes of n‐6 PUFA , SFA , and TFA were estimated to result in 711 800 (95% uncertainty interval [UI] 680 700–745 000), 250 900 (95% UI 236 900–265 800), and 537 200 (95% UI 517 600–557 000) CHD deaths per year wor...