ArticleLiterature Review

Evidence from prospective cohort studies does not support current dietary fat guidelines: A systematic review and meta-analysis

Authors:
  • Hong Kong Baptist University Sport Physical Education and Health
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Abstract

Objectives National dietary guidelines were introduced in 1977 and 1983, by the US and UK governments to reduce coronary heart disease (CHD) mortality by reducing dietary fat intake. Our 2016 systematic review examined the epidemiological evidence available to the dietary committees at the time; we found no support for the recommendations to restrict dietary fat. The present investigation extends our work by re-examining the totality of epidemiological evidence currently available relating to dietary fat guidelines. Methods A systematic review and meta-analysis of prospective cohort studies currently available, which examined the relationship between dietary fat, serum cholesterol and the development of CHD, were undertaken. Results Across 7 studies, involving 89 801 participants (94% male), there were 2024 deaths from CHD during the mean follow-up of 11.9±5.6 years. The death rate from CHD was 2.25%. Eight data sets were suitable for inclusion in meta-analysis; all excluded participants with previous heart disease. Risk ratios (RRs) from meta-analysis were not statistically significant for CHD deaths and total or saturated fat consumption. The RR from meta-analysis for total fat intake and CHD deaths was 1.04 (95% CI 0.98 to 1.10). The RR from meta-analysis for saturated fat intake and CHD deaths was 1.08 (95% CI 0.94 to 1.25). Conclusions Epidemiological evidence to date found no significant difference in CHD mortality and total fat or saturated fat intake and thus does not support the present dietary fat guidelines. The evidence per se lacks generalisability for population-wide guidelines.

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... En una revisión sobre diferentes guías dietéticas se aprecia que el 43 % de los países tienen mensajes sobre la limitación de grasas saturadas, (13) a pesar de que está evidenciado que estas decisiones carecen de evidencia científica (Tabla 1). 14,15,16,17,18,19,20,21,22,23) Tabla 1 -Estudios que cuestionan las recomendaciones alimentarias del consumo de grasa saturada y su relación con enfermedades cardiovasculares Autor/Año Título Número de participantes y de estudios analizados Principales resultados ...
... Harcombe y otros (14) Evidence from prospective cohort studies does not support current dietary fat guidelines: a systematic review and meta-analysis Revisión sistemática y metaanálisis de estudios prospectivos de cohorte. Se analizaron siete estudios para un total de 89 801 participantes. ...
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Introducción: Desde sus inicios, las guías alimentarias han recomendado que el consumo de grasa saturada en la dieta no sobrepase el 10 %, con la finalidad de disminuir las enfermedades cardiovasculares. En aquel entonces, la evidencia sobre la cual se tomó dicha recomendación fue sobreestimada. Aún hoy en día se sigue recomendando dicha reducción a pesar de la gran cantidad de estudios que recomiendan que se reconsidere este límite. Objetivo: Demostrar que el consumo de grasas saturadas en la dieta no representa problemas para la salud humana y que las recomendaciones alimentarias respecto a su limitación deben ser reconsideradas. Métodos: Se realizó una búsqueda de artículos en Pubmed y Google Académico, con las palabras clave: grasas saturadas, recomendaciones dietéticas, enfermedades cardiovasculares, colesterol, evolución humana. Conclusiones: Los metaanálisis y revisiones sistemáticas presentados en este trabajo evidencian que las grasas saturadas no tienen relación con la enfermedad cardiovascular. Su reducción o sustitución con grasas poliinsaturadas omega 6 no previenen los riesgos de desarrollar enfermedades cardiovasculares.
... Others indicate lower risk of CVD when SFA is replaced by PUFA (Hamley 2017;Hooper, Martin, Abdelhamid, and Smith 2015;Jakobsen et al. 2009;Mozaffarian, Micha, and Wallace 2010;Ramsden et al. 2016;Skeaff and Miller 2009). Moreover, many of these more recent meta-analyses indicate no correlation between SFA consumption and CVD related mortality (Hamley 2017;Harcombe, Baker, and Davies 2017;Hooper, Martin, Abdelhamid, and Smith 2015;Ramsden et al. 2016). However, discrepancies highlighted by Hamley (2017) in the heterogeneous controlling variables in many of these metaanalyses, appear to originate from inadequately randomized and controlled trials and indicate a lack of beneficial or adverse effect of SFA on not only total CVD events, but CVD mortality and total mortality. ...
... In fact, most prospective and cohort studies reporting higher CVD risk associated with SFA consumption, are based on the compounded effects induced by reducing certain nutrients (most commonly PUFA) and increasing the SFA content in the diets (Hamley 2017;Hooper, Martin, Abdelhamid, and Smith 2015;Jakobsen et al. 2009;Mozaffarian, Micha, and Wallace 2010;Ramsden et al. 2016;Skeaff and Miller 2009). The remaining few meta-analyses based on the SFA in the diet have recorded no significant effect on CVD risks or CVD related mortality (Chowdhury et al. 2014;Harcombe, Baker, and Davies 2017;Siri-Tarino et al. 2010). Chowdhury et al. (2014) concluded from their review of observational studies of FAs from dietary intake, FA biomarkers as well as randomized controlled trials of FA supplementation that current evidence does not clearly support cardiovascular guidelines favoring higher consumption of PUFAs and lower consumption of total saturated fats. ...
Article
Milk fat is a high-value milk component that is processed mainly as butter, cheese, cream and whole milk powder. It is projected that approximately 35 million tonnes of milk fat will be produced globally by 2025. This surplus, enhances the need for diversification of milk fat products and the milk pool in general. Infant milk formula producers, for instance, have incorporated enzyme modified (“humanised”) milk fat and fat globule phospholipids to better mimic human milk fat structures. Minor components like mono- and di-glycerides from milk fat are increasingly utilized as emulsifiers, replacing palm esters in premium-priced food products. This review examines the chemistry of milk fat and the technologies employed for its modification, fractionation and enrichment. Emerging processing technologies such as ultrasound, high pressure processing, supercritical fluid extraction and fractionation, can be employed to improve the nutritional and functional attributes of milk fat. The potential of recent developments in biological intervention, through dietary manipulation of milk fatty acid profiles in cattle also offers significant promise. Finally, this review provides evidence to help redress the imbalance in reported associations between milk fat consumption and human health, and elucidates the health benefits associated with consumption of milk fat and dairy products.
... For total fat intake, the results from SRMAs of observational studies found that a high total fat intake did not significantly increase risk of CVD mortality (pooled RRs ranging from 0.94 (95%CI: 0.74-1.18) to 1.04 (95%CI: 0.98-1.10)) [6,47] ( Figure 4C) and CHD (pooled RR = 0.93; 95%CI: 0.84-1.03) [6] (Figure 5B). ...
... Evidence from SRMAs of RCTs also indicated that modification of the amount of total fat intake did not significantly decrease risk of all-cause mortality (pooled RRs ranging from 0.98 (95%CI: 0.86-1.12) to 0.99 (95%CI: 0.94-1.05)) [48,49] (Figure 4B Findings from two SRMAs of observational studies showed that high SFA intake was not significantly associated with risk of CVD mortality [6,47] and CHD [6] (see Figures 4B and 5B). However, one SRMA of observational studies found that a high SFA intake was significantly associated with lower risk of ischemic stroke (pooled RR = 0.89; 95%CI: 0.82-0.96) ...
Article
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Unhealthy diet is a significant risk factor for cardiovascular diseases (CVD). Therefore, this umbrella review aims to comprehensively review the effects of dietary factors, including dietary patterns, food groups, and nutrients on CVD risks. Medline and Scopus databases were searched through March 2020. Systematic reviews with meta-analyses (SRMA) of randomized controlled trials (RCTs) or observational studies measuring the effects of dietary factors on CVD risks were eligible. Fifty-four SRMAs, including 35 SRMAs of observational studies, 10 SRMAs of RCTs, and 9 SRMAs of combined RCT and observational studies, were included for review. Findings from the SRMAs of RCTs suggest the significant benefit of Mediterranean and high-quality diets for lowering CVD risk, with pooled risk ratios (RRs) ranging from 0.55 (95%CI: 0.39–0.76) to 0.64 (95%CI: 0.53–0.79) and 0.70 (95%CI: 0.57–0.87), respectively. For food nutrients, two SRMAs of RCTs found that high intake of n-3 polyunsaturated fatty acid (PUFA) significantly reduced CVD risks, with pooled RRs ranging from 0.89 (95%CI: 0.82, 0.98) to 0.90 (95%CI: 0.85–0.96), while evidence of efficacy of n-6 PUFA and combined n-3 and n-6 PUFA were inconsistent. Moreover, results from the SRMAs of RCTs did not find a significant benefit of a low-salt diet and low total fat intake for CVD prevention. For food groups, results from the SRMAs of cohort studies suggest that high intakes of legumes, nuts, and chocolate, as well as a vegetarian diet significantly reduced the risk of coronary heart disease, with pooled RRs of 0.90 (95%CI: 0.84–0.97), 0.68 (95%CI: 0.59–0.78), 0.90 (95%CI: 0.82–0.97), and 0.71 (95%CI: 0.57–0.87), respectively. Healthy dietary patterns had a significant benefit for CVD prevention. With the substitutional and synergistic interactions between different food groups and nutrients, dietary recommendations for CVD prevention should be focused more on healthy dietary patterns than single food groups or nutrients.
... Globally, cardiovascular disease is the most common cause of death. CHD accounted for more than 53% of all CVD-related deaths in 2016, and CHD-related mortality rate increased by 19.0% from 2006 to 2016 [1]. ...
... A previous study reported that high unsaturated fatty acid intake may promote oxidative stress and increase the risk of CHD [17]; further, increased intake of high-fat diet increases the risk of myocardial infarction [18]. However, the relationship remains controversial [19]; a positive association was found between frequent high-fat food consumption and CHD risk in the USA, but not in Europe or Asia [20]. This could be attributed to the different dietary patterns and social conditions, as well as ethnic differences. ...
Article
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Background and aim Coronary heart disease (CHD) is a chronic complex disease caused by a combination of factors such as lifestyle behaviors and environmental and genetic factors. We conducted this study to evaluate the risk factors affecting the development of CHD in Xinjiang, and to obtain valuable information for formulating appropriate local public health policies. Method We conducted a nested case-control study with 277 confirmed CHD cases and 554 matched controls. The association of the risk factors with the risk of CHD was assessed using the multivariate Cox proportional hazard model. Multiplicative interactions were evaluated by entering interaction terms in the Cox proportional hazard model. The additive interactions among the risk factors were assessed by the index of additive interaction. Results The risk of CHD increased with frequent high-fat food consumption, dyslipidemia, obesity, and family history of CHD after adjustment for drinking, smoking status, hypertension, diabetes, family history of hypertension, and family history of diabetes. We noted consistent interactions between family history of CHD and frequent high-fat food consumption, family history of CHD and obesity, frequent high-fat food consumption and obesity, frequent high-fat food consumption and dyslipidemia, and obesity and dyslipidemia. The risk of CHD events increased with the presence of the aforementioned interactions. Conclusions Frequent high-fat food consumption, family history of CHD, dyslipidemia and obesity were independent risk factors for CHD, and their interactions are important for public health interventions in patients with CHD in Xinjiang.
... One meta-analysis of prospective cohort studies by Jakobsen et al. [2] found that replacing 5% of calories from SFA with polyunsaturated fatty acids (PUFA) was associated with a 13% reduced risk of heart disease. Similar results were found in a later meta-analysis by Farvid et al. [3], but other meta-analyses found no associations with SFAs [4][5][6]. These observations are backed up by some meta-analyses of RCTs [7][8][9], but a number of other meta-analyses of RCTs find little evidence that replacing SFA with PUFAs could reduce the risk of heart disease [10][11][12]. ...
Article
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Purpose Saturated fat has long been associated with cardiovascular disease in multiple prospective studies, and randomized controlled trials. Few studies have assessed the relative associations between saturated fat and other macronutrients with hypertension, a major risk factor for cardiovascular disease. The aim of this study was to assess the relative associations between saturated fat, other macronutrients such as monounsaturated and polyunsaturated fat, proteins, and carbohydrates, and incident hypertension in a large prospective cohort of French women. Methods This study used data from the E3N cohort study, including participants free of hypertension at baseline. A food frequency questionnaire was used to determine dietary intakes of saturated fat (SFA), monounsaturated fat (MUFA), polyunsaturated fat (PUFA), animal protein (AP), vegetable protein (VP), carbohydrates (CH) and various foods. Cases of hypertension were based on self-report, validated by drug reimbursement data. Covariates were based on self-report. Cox proportional hazard models were used to estimate the relative associations between different macronutrients and hypertension risk, using the ‘substitution’ framework. Bootstrapping was used to generate 95% confidence intervals. Results This study included 45,854 women free of hypertension at baseline. During 708,887 person-years of follow-up, 12,338 incident cases of hypertension were identified. Compared to saturated fat, higher consumption of all other macronutrients was associated with a lower risk of hypertension (HRMUFA = 0.74 [0.67: 0.81], HRPUFA = 0.84 [0.77: 0.92], HRCH = 0.83 [0.77: 0.88], HRAP = 0.91 [0.85: 0.97], HRVP = 0.93 [0.83: 1.03]). Conclusion This study finds that relative to other macronutrients such as monounsaturated or polyunsaturated fat, higher intake of saturated fat is associated with a higher risk of hypertension among women.
... This article also allowed a reassessment of the current guideline recommendations regarding food intake and suggested some proposals for their modification. The authors emphasized that the US dietary guidelines [3] recommend limiting the intake of saturated fatty acid (SFA) to <10% of total calories in order to reduce cardiovascular disease, despite evidence that a number of foods containing saturated fat, including dairy products such as yogurt, dark chocolate and unprocessed meat, are not associated with an increased risk of cardiovascular disease or diabetes [4][5][6][7]. The authors concluded that there was no solid evidence that the limits on saturated fat consumption, currently recommended by the U.S. guidelines, are able to prevent cardiovascular diseases or reduce mortality [2]. ...
Article
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Dietary habits have major implications as causes of death globally, particularly in terms of cardiovascular disease, cancer and diabetes, but to precisely define the role of the single components of diet in terms of cardiovascular risk is not an easy task, since current epidemiological cohorts do not include sufficient information regarding all the confounding factors typical of nutritional associations. As an example, complex and multifactorial are the possible nutritional or detrimental effects of dietary fats, due to the huge variety of lipid metabolites originating from either the enzymatic or non-enzymatic oxidation of polyunsaturated fatty acids, cholesterol and phospholipids. The area of research that has allowed the benefit/risk profile of a dietary supplement to be tested with controlled studies is that of omega-3 fatty acids. Omega-3 fatty acids have showed a potential therapeutic role only in secondary cardiovascular prevention, while controlled studies in primary prevention have consistently produced neutral results. Despite some favorable evidence in patients with chronic heart failure; a treatment with n-3 PUFA in this clinical context is presently overlooked. The potential risk of atrial fibrillation, especially when n-3 PUFA are used in high doses, is still under scrutiny.
... Observándose deficiencias en la población de estos y otros macronutrientes en quienes no consumen productos de origen animal (Larpin et al., 2019;Rocha et al., 2019;Chong et al., 2020) Es preciso señalar que en estudios médicos y de nutrición humana los ensayos aleatorizados controlados son considerados como la forma más fiable de evidencia científica, porque eliminan mayormente las formas de sesgo. Como se señaló anteriormente este tipo de estudios señala que no existe relación alguna entre consumo de grasas saturadas y enfermedades cardiovasculares, ni tampoco con la mortalidad total (Teicholz, 2015;Harcombe et al., 2017b). En efecto las carnes rojas contribuyen con ácidos grasos beneficiosos para la salud, destacando aquellos que se observan en animales provenientes de sistemas pastoriles (McAfee et al., 2010), como es el caso chileno. ...
... Dietary fat or fatty acid intake in relation to cardiovascular disease (CVD) and stroke. Results of meta-analyses published between 2012 and 2017 (see Annex Table S1) [377,379,381,382,[388][389][390][391][392][393][394][395][396][397][398][399][400][401][402][403][404][405] Consumption of total fat and saturated fat (in % of energy intake) is not clearly associated with cardiovascular morbidity and mortality. A small but potentially important benefit regarding cardiovascular risk results from the (total/partial) replacement of saturated fat with polyunsaturated fat. ...
Technical Report
Given the limited amount of current evidence linking total water intake to health outcomes, further data would be needed to guide evidence-based recommendations on water intake. In particular, scientific evidence on the levels of long-term water intake needed to reduce the risk of common chronic diseases is currently limited.
... The inclusion of only empirical articles is due to the inclusion of statistically validated factors that determine GBE. This approach is used in the literature in the PRISMA method when applying SLR to areas, such as medicine [86,[94][95][96][97], management [88,98], consumer behavior [99], tourism [100], and others [81,85,90]. Work-in-progress papers and editorials; -Practice guidelines; -Book chapters and reviews; -Conference publications, including proceedings, posters, and abstracts. ...
Article
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Our study aims to analyze factors determining the green brand equity (GBE) based on a systematic literature review (SLR) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. We posed 3 research questions and searched five databases (Scopus, Web of Sciences, Google Scholar, EBSCO, and Elsevier) for studies containing the term ‘green brand equity’ and the combination of two terms: ‘brand equity’ and ‘green’. Additionally, the backward and forward snowballing methods were applied. In our SLR, we included empirical studies published between 2006 and 2021 as peer-reviewed papers in English. Exclusion criteria included studies with theoretical models, studies describing brand equity not related to GBE, Ph.D. thesis, short reports, workshop papers, practice guidelines, book chapters, reviews, and conference publications. Finally, 33 articles were analyzed as part of the SLR in two fields: general information (authorship, year of publication, type of study, research country or location, sample size, and product categories), and research specifications (factors or variables, number and type of hypotheses, scale or measurement items, type of statistical analysis, and selected indicators of statistical methods). Image, trust, value, satisfaction, and loyalty appeared to be the most studied determinants of GBE. Less frequently analyzed were quality, awareness, attributes, particular promotional activities, and the fact of purchase. The results obtained are important in practical terms, showing what to consider when creating GBE in different categories of products and services.
... weder mit kardiovaskulärer Sterblichkeit noch mit Gesamtsterblichkeit assoziiert ist [7,17,75]. Metaanalysen haben die Studien zusammenhängend gewichtet und bewertet [76][77][78][79][80][81][82] und die fehlende Assoziation zwischen SFA-Konsum und KHK bestätigt. Auch zwischen der Blutkonzentration an SFA und KHK konnte kein Zusammenhang beobachtet werden [79], was auch bei einer deutschen Kohorte in der LURIC(Ludwigshafen Risk and Cardiovascular Health)-Studie bestätigt wurde [83]. ...
Article
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Zusammenfassung Die „Fetthypothese der koronaren Herzkrankheit“, derzufolge „gesättigte Fettsäuren“ („saturated fatty acids“, SFA) die LDL(„low-density lipoprotein“)-Cholesterin-Konzentration (LDL-C) steigern und folglich das Risiko für kardiovaskuläre Erkrankungen erhöhen, prägte die Ernährungsempfehlungen der letzten 60 Jahre, zunächst in den USA und später auch in Europa. Über die Jahre mehrte sich Evidenz aus Epidemiologie und kontrollierten klinischen Studien, dass der Konsum von SFA per se nicht mit einem erhöhten kardiovaskulären Risiko einhergeht bzw. die Einschränkung des Konsums von SFA keine präventive Wirkung zeigt. Die Fokussierung auf den SFA-Gehalt negiert die biologisch heterogenen und zum Teil biologisch günstigen Wirkungen unterschiedlicher SFA. Zudem wird hierbei außer Acht gelassen, dass SFA in intakten Lebensmitteln in unterschiedliche komplexe Matrizes eingebunden sind, die aus Dutzenden Nährstoffen mit unterschiedlicher Struktur und Begleitstoffen bestehen und damit jeweils unterschiedliche biologische Antworten und metabolische Effekte auslösen. Entsprechend sind solche nährstoffbasierten Empfehlungen prinzipiell wenig zielführend und zudem schlecht umsetzbar. Hinzu kommt, dass LDL‑C kein geeigneter Marker ist, um den Effekt von Lebensstilintervention wie der Ernährung oder aber der körperlichen Aktivität auf das globale kardiovaskuläre Risiko zu beurteilen.
... [ [47][48][49][50][51][52][53][54] Reach a low n-6:n-3 ratio ...
Article
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Research coupling human nutrition and sustainability concerns is a rapidly developing field, which is essential to guide governments' policies. This critical and comprehensive review analyzes indicators and approaches to "sustainable healthy diets" published in the literature since this discipline's emergence a few years ago, identifying robust gauges and highlighting the flaws of the most commonly used models. The reviewed studies largely focus on one or two domains such as greenhouse gas emissions or water use, while overlooking potential impact shifts to other sectors or resources. The present study covers a comprehensive set of indicators from the health, environmental and socio-economic viewpoints. This assessment concludes that in order to identify the best food option in sustainability assessments and nutrition analysis of diets, some aspects such as the classification and disaggregation of food groups, the impacts of the rates of local food consumption and seasonality, preservation methods, agrobiodiversity and organic food and different production systems, together with consequences for low-income countries, require further analysis and consideration.
... The most researched was the effect of SFAs via cohort studies and its manipulation with unsaturated fatty acids in RCTs. Cohort studies provided conflicting evidence, more frequently finding no association with cardiovascular outcomes(Cheng et al. 2016;Chowdhury et al. 2014;Harcombe, Baker, and Davies 2017; Muto, Momoko and Osamu 2018; Siri-Tarino et al. 2010; Te Morenga and Montez 2017; Zhu, Bo, and Liu 2019). SLRs of RCTs that manipulated the ratio of fatty acid categories show strong evidence for the replacement of SFAs with PUFA, and potentially MUFA. ...
Article
Dietary guidelines for many Western countries base their edible oil and fat recommendations solely on saturated fatty acid content. This study aims to demonstrate which nutritional and bioactive components make up commonly consumed edible oils and fats; and explore the health effects and strength of evidence for key nutritional and bioactive components of edible oils. An umbrella review was conducted in several stages. Food composition databases of Australia and the United States of America, and studies were examined to profile nutrient and bioactive content of edible oils and fats. PUBMED and Cochrane databases were searched for umbrella reviews, systematic literature reviews of randomized controlled trials or cohort studies, individual randomized controlled trials, and individual cohort studies to examine the effect of the nutrient or bioactive on high-burden chronic diseases (cardiovascular disease, type 2 diabetes mellitus, obesity, cancer, mental illness, cognitive impairment). Substantial systematic literature review evidence was identified for fatty acid categories, tocopherols, biophenols, and phytosterols. Insufficient evidence was identified for squalene. The evidence supports high mono- and polyunsaturated fatty acid compositions, total biophenol content, phytosterols, and possibly high α-tocopherol content as having beneficial effects on high-burden health comes. Future dietary guidelines should use a more sophisticated approach to judge edible oils beyond saturated fatty acid content.
... Although the ratio of SFA to MUFA and PUFA is nutritionally suitable (approximately 1:1), its negative effects on blood lipids (e.g., undesired increase in TAG, total and LDL-C levels, and/or decreased HDL-C levels) are continuously discussed due to its high SFA content (Marangoni et al. 2017). On the other hand, when analyzed, the literature demonstrated that there is no clear consensus on some oil types containing SFAs and CVD to date (Harcombe, Baker, and Davies 2017). Likewise, a comprehensive review including large meta-analyses has also reported that reducing SFAs did not have any beneficial effect on mortality and CVDs. ...
Article
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The public health debate about fats and human health has been ongoing for a long time. Specifically, the fat types commonly used in the food industry and the techniques used in extracting them are remarkable in terms of human health. Among these, palm oil, which is mainly associated with cardiovascular disease (CVD), is a vegetable oil type that is widely used in the food industry. Moreover, the fractionation of palm oil has become quite common in the food industry when compared to other culinary oils and fats. Fractional crystallization, which has been recently regarded as an alternative to hydrogenization and interesterification methods, has become more popular in edible oil technology, even though it is an ancient method. The main fractions of palm oil are palm olein and palm stearin. Palm oil fractions, which have some pros and cons, are used in edible oils, such as margarine/shortening, as well as bread and cake-like pastry production. Since the fatty acid composition of palm oil, palm kernel oil, and their fractions is different, each type of oil needs to be evaluated separately with regards to their CVD effects and food preparation applications. However, the effects of the fractionation method and the fractional palm oil produced on health are controversial in the literature. In this review, the use of palm oil produced via the fractional crystallization method in the food industry and its potential CVD effects were evaluated.
... In the past 2 decades, there were numerous of evidence from well-designed metabolic studies, prospective cohorts, and randomized clinical trials. Several meta-analysis of prospective cohort studies find no evidence that reduction of SFA may reduce CVD incidence (Harcombe et al., 2017;Siri-Tarino et al., 2010). Last month, a prospective cohort study involved 2,731 participants showed that higher levels of γ-linolenic acid, a type of n-6 polyunsaturated fatty acid (PUFA), were associated with higher type 2 diabetes incidence (Miao et al., 2020). ...
... One major shift in nutritional thinking has been with respect to the role of fat. Indeed, there is evidence that restricting total fat intake leads to higher carbohydrate intake, resulting in increases in obesity and diabetes (Harcombe, Baker & Davies, 2017). In a systematic review and metaanalysis across low-, middle-, and highincome countries, Sartorius et al. (2018) concluded that a high-carbohydrate diet, or an increased percentage of total energy intake in the form of carbohydrates, correspondingly increased the odds of obesity. ...
Article
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Overweight and obesity in Malaysia pose serious threats to health. Prevalence has escalated to alarming levels in recent decades despite a multitude of public health dietary messages geared towards obesity prevention and health promotion. Gaps between health messages, messengers, and the public must be identified and closed to effectively combat obesity and overweight. This review article aims to examine public health dietary messages, guidelines, and programmes for the prevention of obesity in Malaysia, and explore potential reasons for the continued rise in its prevalence. Public health dietary communication in Malaysia has progressed and improved substantially over the years. However, most messages have been designed for the general audience, with little consideration of differences in physical, social, cultural, and environmental backgrounds, and varying levels of comprehension. We offer several recommendations to increase the effectiveness of public health dietary messages in fighting the obesity epidemic, based on a cross sectoral, place-based approach that recognise the complexity of the underlying causes of obesity. Keywords: Public health dietary messaging; obesity; Malaysia; place-based approach; cross-sectoral approaches
... 89,800 participants) found epidemiological research that pointed to no significant difference in CHD mortality and total fat or saturated fat intake. These findings do not support the present dietary fat guidelines [63]. Therefore, further research is needed and, at the same time, action to improve public health is important. ...
Article
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The main aim of this study was to identify the sources of energy and 25 nutrients in fats and oils in the average Polish diet. We analyzed energy, total fat, saturated fatty acids (SFAs), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), cholesterol, protein, carbohydrates, nine minerals, and nine vitamins. We included five sub-groups: butter, vegetable oils, margarine and other hydrogenated vegetable fats, olive oil, and other animal fats. The basis for our analysis was data from the 2016 household budget survey, conducted on a representative sample of the Polish population (36,886 households, n = 99,230). We used the cluster analysis to assess the impact of socio-demographic and economic factors on the volume of fats and oil consumption and on the share of particular products in the supply of energy and nutrients. Our findings indicated that fats and oils contributed 32.9% of the total fat supply, which placed these products in first position among main food groups. Meat and its products ranked second (30.8%) in the total fat supply, while milk and dairy products, including cream (13.4%), were the third food group. The second position in the total fat supply was taken by meat and its products (30.8%), and the third place was taken by milk and dairy products, including cream (13.4%). The supply of fatty acids from fats and oils varied and ranged from 45.6% for PUFA to 31.5% for MUFA to 27.8% for SFA. The supply of cholesterol was at the level of 8.3%. Our research has proven that fats and oils are an important source of vitamin E, providing almost half of the daily supply of this vitamin to the average Polish diet. The supply of vitamin A and D equaled 16–18% of their total daily intake. In the cluster analysis, we identified five clusters that differed in the consumption of butter, oils, margarine and other vegetable fats, olive oil, and other animal fats. The variables with most differentiating clusters were: education level, income (in quintile groups of households), degree of urbanization of the place of household residence, and socio-economic type of the household. Our results indicate a high share of fats and oils in the total fat supply and should be used to evaluate the diets from a nutritional and health point of view.
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Purpose of Review This narrative review summarizes the current peer-reviewed literature and mechanisms surrounding the cardiovascular health impact of coconut oil. Recent Findings No randomized controlled trials (RCTs) and/or prospective cohort studies have investigated the effect or association of coconut oil with cardiovascular disease. Evidence from RCTs indicated that coconut oil seems to have less detrimental effects on total and LDL-cholesterol compared to butter, but not compared to cis-unsaturated vegetable oils, such as safflower, sunflower, or canola oil. The isocaloric replacement (by 1% of energy intake) of carbohydrates with lauric acid (the predominant fatty acid in coconut oil) increased total cholesterol by 0.029 mmol/L (95% CI: 0.014; 0.045), LDL-cholesterol by 0.017 mmol/L (0.003; 0.031), and HDL-cholesterol by 0.019 mmol/L (0.016; 0.023). Summary The current evidence from shorter term RCTs suggests that replacement of coconut oil with cis-unsaturated oils lowers total and LDL-cholesterol, whereas for the association between coconut oil intake and cardiovascular disease, less evidence is available.
Article
Background: Previous meta-analyses included abundant cross-sectional studies, and/or only assessed high versus low categories of UPF consumption. We conducted this meta-analysis based on prospective cohort studies to estimate the dose-response associations of UPF consumption with the risk of cardiovascular events (CVEs) and all-cause mortality among general adults. Methods: PubMed, Embase, and Web of Science were searched for relevant articles published up to August 17, 2021, and newly published articles between August 17, 2021 and July 21, 2022 were re-searched. Random-effects models were used to estimate the summary relative risks (RRs) and confidence intervals (CIs). Generalized least squares regression was used to estimate the linear dose-response associations of each additional serving of UPF. Restricted cubic splines were used to model the possible nonlinear trends. Results: Eleven eligible papers (17 analyses) were finally identified. The pooled effect size for the highest versus lowest category of UPF consumption showed positive associations with the risk of CVEs (RR = 1.35, 95% CI, 1.18-1.54) and all-cause mortality (RR = 1.21, 95% CI, 1.15-1.27). For each additional daily serving of UPF, the risk increased by 4% (RR = 1.04, 95% CI, 1.02-1.06) for CVEs and 2% (RR = 1.02, 95% CI, 1.01-1.03) for all-cause mortality. With increasing UPF intake, the risk of CVEs reflected a linear upward trend (Pnonlinearity = 0.095), while all-cause mortality reflected a nonlinear upward trend (Pnonlinearity = 0.039). Conclusion: Our findings based on prospective cohorts suggested that any increased level of UPF consumption was linked to higher CVEs and mortality risk. Thus, the recommendation is to control the intake of UPF in daily diet.
Article
Background Reducing the intake of total fat, saturated fatty acids (SFA) and dietary cholesterol was a cornerstone of dietary guidance in past decades. This emphasis shifted recently from lowering the intake of total fat to focusing on the quality of dietary fat intake, the avoidance of industrial trans-fatty acids (TFA), and the substitution of SFA with unsaturated fatty acids. There is also a trend towards investigating diet-disease associations of fatty foods rather than nutrients. Scope and approach We aimed to summarize comprehensively the currently available evidence for total dietary fat, fat quality, and fatty foods such as butter, vegetable oils, nuts and seeds on risk of non-communicable diseases including cardiovascular disease (and its risk factors), cancer, type 2 diabetes, and neurodegenerative diseases. Key findings and conclusions The findings from systematic reviews of prospective observational studies, which often compared extreme intake categories, found mainly no association of total fat, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and SFA with risk of non-communicable diseases. Systematic reviews of randomized controlled trials indicate that SFA and/or TFA substitution with MUFA and/or PUFA improves blood lipids and markers of glycemic control (observed only for SFA replacement), with the effect of PUFA being more pronounced. A higher intake of total TFA was associated increased risk of cardiovascular disease. In line with current dietary guidelines, the available published evidence deems it reasonable to recommend replacement of SFA with MUFA and PUFA and avoidance of consumption of industrial TFA.
Article
Background Cardiovascular disease (CVD) is the leading global cause of death. For decades, the conventional wisdom has been that the consumption of saturated fat (SFA) undermines cardiovascular health, clogs the arteries, increases risk of CVD and leads to heart attacks. It is timely to investigate whether this claim holds up to scientific scrutiny. Objectives The purpose of this paper is to review and discuss recent scientific evidence on the association between dietary SFA and CVD. Methods PubMed, Google scholar and Scopus were searched for articles published between 2010 and 2021 on the association between SFA consumption and CVD risk and outcomes. A review was conducted examining observational studies and prospective epidemiologic cohort studies, RCTs, systematic reviews and meta analyses of observational studies and prospective epidemiologic cohort studies and long-term RCTs. Results Collectively, neither observational studies, prospective epidemiologic cohort studies, RCTs, systematic reviews and meta analyses have conclusively established a significant association between SFA in the diet and subsequent cardiovascular risk and CAD, MI or mortality nor a benefit of reducing dietary SFAs on CVD rick, events and mortality. Beneficial effects of replacement of SFA by polyunsaturated or monounsaturated fat or carbohydrates remain elusive. Conclusions Findings from the studies reviewed in this paper indicate that the consumption of SFA is not significantly associated with CVD risk, events or mortality. Based on the scientific evidence, there is no scientific ground to demonize SFA as a cause of CVD. SFA naturally occurring in nutrient-dense foods can be safely included in the diet.
Article
Background Reducing the intake of total fat, saturated fatty acids (SFA) and dietary cholesterol was a cornerstone of dietary guidance in past decades. This emphasis shifted recently from lowering the intake of total fat to focussing on the quality of dietary fat intake, the avoidance of industrial trans-fatty acids (TFA), and the substitution of SFA with unsaturated fatty acids. There is also a trend towards investigating diet-disease associations of fatty foods rather than nutrients. Scope and approach We aimed to summarize comprehensively the currently available evidence for total dietary fat, fat quality, and fatty foods such as butter, vegetable oils, nuts and seeds on risk of non-communicable diseases including cardiovascular disease (and its risk factors), cancer, type 2 diabetes, and neurodegenerative diseases. Key findings and conclusions The findings from systematic reviews of prospective observational studies, which often compared extreme intake categories, found mainly no association of total fat, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and SFA with risk of non-communicable diseases. Systematic reviews of randomized controlled trials indicate that SFA and/or TFA substitution with MUFA and/or PUFA improves blood lipids and markers of glycemic control (observed only for SFA replacement), with the effect of PUFA being more pronounced. A higher intake of total TFA was associated increased risk of cardiovascular disease. In line with current dietary guidelines, the available published evidence deems it reasonable to recommend replacement of SFA with MUFA and PUFA and avoidance of consumption of industrial TFA.
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Introducción: Desde sus inicios, las guías alimentarias han recomendado que el consumo de grasa saturada en la dieta no sobrepase el 10 %, con la finalidad de disminuir las enfermedades cardiovasculares. En aquel entonces, la evidencia sobre la cual se tomó dicha recomendación fue sobreestimada. Aún hoy en día se sigue recomendando dicha reducción a pesar de la gran cantidad de estudios que recomiendan que se reconsidere este límite. Objetivo: Demostrar que el consumo de grasas saturadas en la dieta no representa problemas para la salud humana y que las recomendaciones alimentarias respecto a su limitación deben ser reconsideradas. Métodos: Se realizó una búsqueda de artículos en Pubmed y Google Académico, con las palabras clave: grasas saturadas, recomendaciones dietéticas, enfermedades cardiovasculares, colesterol, evolución humana. Conclusiones: Los metaanálisis y revisiones sistemáticas presentados en este trabajo evidencian que las grasas saturadas no tienen relación con la enfermedad cardiovascular. Su reducción o sustitución con grasas poliinsaturadas omega 6 no previenen los riesgos de desarrollar enfermedades cardiovasculares. Palabras clave: grasa saturada; recomendaciones dietéticas; evolución.
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Introduction: We conducted a scoping review of dietary guidelines with the intent of developing a position paper by the "IUNS Task force on Dietary Fat Quality" tasked to summarize the available evidence and provide the basis for dietary recommendations. Methods: We systematically searched several databases and Web sites for relevant documents published between 2015 and 2019. Results: Twenty documents were included. Quantitative range intake recommendations for daily total fat intake included boundaries from 20 to 35% of total energy intake (TEI), for monounsaturated fat (MUFA) 10-25%, for polyunsaturated fat (PUFA) 6-11%, for saturated-fat (SFA) ≤11-≤7%, for industrial trans-fat (TFA) ≤2-0%, and <300-<200 mg/d for dietary cholesterol. The methodological approaches to grade the strength of recommendations were heterogeneous, and varied highly between the included guidelines. Only the World Health Organization applied the GRADE approach and graded the following recommendation as "strong": to reduce SFA to below 10%, and TFA to below 1% and replace both with PUFA if SFA intake is greater than 10% of TEI. Conclusion: Although the methodological approaches of the dietary guidelines were heterogeneous, most of them recommend total fat intakes of 30-≤35% of TEI, replacement of SFA with PUFA and MUFA, and avoidance of industrial TFA.
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Background Dietary guidelines recommend limiting red meat intake because it is a major source of medium- and long-chain SFAs and is presumed to increase the risk of cardiovascular disease (CVD). Evidence of an association between unprocessed red meat intake and CVD is inconsistent. Objective The study aimed to assess the association of unprocessed red meat, poultry, and processed meat intake with mortality and major CVD. Methods The Prospective Urban Rural Epidemiology (PURE) Study is a cohort of 134,297 individuals enrolled from 21 low-, middle-, and high-income countries. Food intake was recorded using country-specific validated FFQs. The primary outcomes were total mortality and major CVD. HRs were estimated using multivariable Cox frailty models with random intercepts. Results In the PURE study, during 9.5 y of follow-up, we recorded 7789 deaths and 6976 CVD events. Higher unprocessed red meat intake (≥250 g/wk vs. <50 g/wk) was not significantly associated with total mortality (HR: 0.93; 95% CI: 0.85, 1.02; P-trend = 0.14) or major CVD (HR: 1.01; 95% CI: 0.92, 1.11; P-trend = 0.72). Similarly, no association was observed between poultry intake and health outcomes. Higher intake of processed meat (≥150 g/wk vs. 0 g/wk) was associated with higher risk of total mortality (HR: 1.51; 95% CI: 1.08, 2.10; P-trend = 0.009) and major CVD (HR: 1.46; 95% CI: 1.08, 1.98; P-trend = 0.004). Conclusions In a large multinational prospective study, we did not find significant associations between unprocessed red meat and poultry intake and mortality or major CVD. Conversely, a higher intake of processed meat was associated with a higher risk of mortality and major CVD.
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Introduction: We conducted a scoping review of systematic reviews (SRs) on dietary fat intake and health outcomes in human adults within the context of a position paper by the "International Union of Nutritional Sciences Task force on Dietary Fat Quality" tasked to summarize the available evidence and provide dietary recommendations. Methods: We systematically searched several databases for relevant SRs of randomized controlled trials (RCTs) and/or prospective cohort studies published between 2015 and 2019 assessing the association between dietary fat and health outcomes. Results: Fifty-nine SRs were included. The findings from SRs of prospective cohort studies, which frequently compare the highest versus lowest intake categories, found mainly no association of total fat, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and saturated fatty acid (SFA) with risk of chronic diseases. SRs of RCTs applying substitution analyses indicate that SFA replacement with PUFA and/or MUFA improves blood lipids and glycemic control, with the effect of PUFA being more pronounced. A higher intake of total trans-fatty acid (TFA), but not ruminant TFA, was probably associated with an increased risk of mortality and cardiovascular disease based on existing SRs. Conclusion: Overall, the available published evidence deems it reasonable to recommend replacement of SFA with MUFA and PUFA and avoidance of consumption of industrial TFA.
Article
SFAs play the leading role in 1 of the greatest controversies in nutrition science. Relative to PUFAs, SFAs generally increase circulating concentrations of LDL cholesterol, a risk factor for atherosclerotic cardiovascular disease (ASCVD). However, the purpose of regulatory mechanisms that control the diet-induced lipoprotein cholesterol dynamics is rarely discussed in the context of human adaptive biology. We argue that better mechanistic explanations can help resolve lingering controversies, with the potential to redefine aspects of research, clinical practice, dietary advice, public health management, and food policy. In this paper we propose a novel model, the homeoviscous adaptation to dietary lipids (HADL) model, which explains changes in lipoprotein cholesterol as adaptive homeostatic adjustments that serve to maintain cell membrane fluidity and hence optimal cell function. Due to the highly variable intake of fatty acids in humans and other omnivore species, we propose that circulating lipoproteins serve as a buffer to enable the rapid redistribution of cholesterol molecules between specific cells and tissues that is necessary with changes in dietary fatty acid supply. Hence, circulating levels of LDL cholesterol may change for nonpathological reasons. Accordingly, an SFA-induced raise in LDL cholesterol in healthy individuals could represent a normal rather than a pathologic response. These regulatory mechanisms may become disrupted secondarily to pathogenic processes in association with insulin resistance and the presence of other ASCVD risk factors, as supported by evidence showing diverging lipoprotein responses in healthy individuals as opposed to those with metabolic disorders such as insulin resistance and obesity. Corresponding with the model, we suggest alternative contributing factors to the association between elevated LDL cholesterol concentrations and ASCVD, involving dietary factors beyond SFAs, such as an increased endotoxin load from diet–gut microbiome interactions and subsequent chronic low-grade inflammation that interferes with fine-tuned signaling pathways.
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Purpose of review: There is an extensive literature on the efficacy of the low carbohydrate diet (LCD) for weight loss, and in the improvement of markers of the insulin-resistant phenotype, including a reduction in inflammation, atherogenic dyslipidemia, hypertension, and hyperglycemia. However, critics have expressed concerns that the LCD promotes unrestricted consumption of saturated fat, which may increase low-density lipoprotein (LDL-C) levels. In theory, the diet-induced increase in LDL-C increases the risk of cardiovascular disease (CVD). The present review provides an assessment of concerns with the LCD, which have focused almost entirely on LDL-C, a poor marker of CVD risk. We discuss how critics of the LCD have ignored the literature demonstrating that the LCD improves the most reliable CVD risk factors. Recent findings: Multiple longitudinal clinical trials in recent years have extended the duration of observations on the safety and effectiveness of the LCD to 2-3 years, and in one study on epileptics, for 10 years. Summary: The present review integrates a historical perspective on the LCD with a critical assessment of the persistent concerns that consumption of saturated fat, in the context of an LCD, will increase risk for CVD.
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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 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, eggs 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.
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Low-carb diets have been shown to reverse type 2 diabetes in some people. George Winter investigates the latest findings
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The UK has made significant progress in the prevention and treatment of viral hepatitis, yet the prevalence of severity of liver disease continues to rise. George Winter discusses the role of alcohol consumption and obesity in this changing epidemiology.
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The American Heart Association (AHA) recently published a meta-analysis that confirmed their 60-year-old recommendation to limit saturated fat (SFA, saturated fatty acid) and replace it with polyunsaturated fat to reduce the risk of heart disease based on the strength of 4 Core Trials. To assess the evidence for this recommendation, meta-analyses on the effect of SFA consumption on heart disease outcomes were reviewed. Nineteen meta-analyses addressing this topic were identified: 9 observational studies and 10 randomized controlled trials. Meta-analyses of observational studies found no association between SFA intake and heart disease, while meta-analyses of randomized controlled trials were inconsistent but tended to show a lack of an association. The inconsistency seems to have been mediated by the differing clinical trials included. For example, the AHA meta-analysis only included 4 trials (the Core Trials), and those trials contained design and methodological flaws and did not meet all the predefined inclusion criteria. The AHA stance regarding the strength of the evidence for the recommendation to limit SFAs for heart disease prevention may be overstated and in need of reevaluation.
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CVD remains the greatest cause of death globally, and with the escalating prevalence of metabolic diseases, including type-2 diabetes, CVD mortality is predicted to rise. While the replacement of SFA has been the cornerstone of effective dietary recommendations to decrease CVD risk since the 1980s, the validity of these recommendations have been recently challenged. A review of evidence for the impact of SFA reduction revealed no effect on CVD mortality, but a significant reduction in risk of CVD events (7–17%). The greatest effect was found when SFA were substituted with PUFA, resulting in 27% risk reduction in CVD events, with no effect of substitution with carbohydrate or protein. There was insufficient evidence from randomised controlled trials to conclude upon the impact of SFA replacement with MUFA on CVD and metabolic outcomes. However, there was high-quality evidence that reducing SFA lowered serum total, and specifically LDL-cholesterol, a key risk factor for CVD, with greatest benefits achieved by replacing SFA with unsaturated fats. The exchange of SFA with either PUFA or MUFA, also produced favourable effects on markers of glycaemia, reducing HbA1c, a long-term marker of glycaemic control. In conclusion, the totality of evidence supports lowering SFA intake and replacement with unsaturated fats to reduce the risk of CVD events, and to a lesser extent, cardiometabolic risk factors, which is consistent with current dietary guidelines.
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It is not clear whether a saturated fatty acid-rich palm olein diet has any significant adverse effect on established surrogate lipid markers of cardiovascular disease (CVD) risk. We reviewed the effect of palm olein with other oils on serum lipid in healthy adults. We searched in MEDLINE and CENTRAL: Central Register of Controlled Trials from 1975 to January 2018 for randomized controlled trials of ≥2 wk intervention that compared the effects of palm olein (the liquid fraction of palm oil) with other oils such as coconut oil, lard, canola oil, high-oleic sunflower oil, olive oil, peanut oil, and soybean oil on changes in serum lipids. Nine studies were eligible and were included, with a total of 533 and 542 subjects on palm olein and other dietary oil diets, respectively. We extracted and compared all the data for serum lipids, such as total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglyceride, and TC/HDL cholesterol ratio. When comparing palm olein with other dietary oils, the overall weighted mean differences for TC, LDL cholesterol, HDL cholesterol, triglycerides, and the TC/HDL cholesterol ratio were -0.10 (95% CI: -0.30, 0.10; P = 0.34), -0.06 (95% CI: -0.29,0.16; P = 0.59), 0.02 (95% CI: -0.01, 0.04; P = 0.20), 0.01 (95% CI: -0.05, 0.06; P = 0.85), and -0.15 (95% CI: -0.43, 0.14; P = 0.32), respectively. Overall, there are no significant differences in the effects of palm olein intake on lipoprotein biomarkers (P > 0.05) compared with other dietary oils. However, dietary palm olein was found to have effects comparable to those of other unsaturated dietary oils (monounsaturated fatty acid- and polyunsaturated fatty acid-rich oils) but differed from that of saturated fatty acid-rich oils with respect to the serum lipid profile in healthy adults.
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Objective To investigate trends in total fat and fatty acid intakes and chronic health conditions among Korean adults over nine years between 2007 and 2015. Design Cross-sectional, observational study using a stratified, multistage probability sampling design at a national level. Intakes of total fat and fatty acids were estimated from 24 h dietary recalls by sex and age groups. Trends of total fat and fatty acid intakes were determined by multiple linear regression after adjusting for covariates. Trends in age-standardized prevalence of obesity, hypercholesterolaemia and hypertriacylglycerolaemia were examined by sex. Setting Korea. Participants Population data of 47749 healthy adults (aged ≥19 years) derived from the Korea National Health and Nutrition Examination Survey between 2007 and 2015. Results Over the survey period, daily intakes of energy and total, saturated, monounsaturated, polyunsaturated, n -3 and n -6 fats (grams and percentage of energy (%E)) increased steadily. In all sex and age groups, significant increases were seen in SFA intake from 9·9 g (4·7 %E) to 12·0 g (5·3 %E) and in MUFA intake from 9·9 g (4·6 %E) to 13·3 g (5·8 %E). The prevalence of hypercholesterolaemia increased from 10·7 to 17·9 % over the same period. Conclusions In Korean adults, total fat, SFA and other fatty acids have been increasing along with the prevalence of hypercholesterolaemia. This information can help set adequate macronutrient and fatty acid distribution ranges in developing population-specific preventive strategies against diet-related illness.
Article
US public health dietary advice was announced by the Select Committee on Nutrition and Human needs in 1977 and was followed by UK public health dietary advice issued by the National Advisory Committee on Nutritional Education in 1983. Dietary recommendations in both cases focused on reducing dietary fat intake; specifically to (i) reduce overall fat consumption to 30% of total energy intake and (ii) reduce saturated fat consumption to 10% of total energy intake. The recommendations were an attempt to address the incidence of coronary heart disease. These guidelines have been reiterated in the Dietary Guidelines for Americans since the first edition in 1980. The most recent edition has positioned the total fat guideline with the use of ‘Acceptable Macronutrient Distribution Ranges’. The range given for total fat is 20%–35% and the AMDR for saturated fat is given as <10%—both as a percentage of daily calorie intake. In February 2018, the Center for Nutrition Policy and Promotion announced ‘The US Departments of Agriculture and Health and Human Services currently are asking for public comments on topics and supporting scientific questions to inform our development of the 2020–2025 Dietary Guidelines for Americans’. Public comments were invited on a number of nutritional topics. The question asked about saturated fats was: ‘What is the relationship between saturated fat consumption (types and amounts) during adulthood and risk of cardiovascular disease?’ This article is a response to that question.
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Purpose of review: Despite the American public following recommendations to decrease absolute dietary fat intake and specifically decrease saturated fat intake, we have seen a dramatic rise over the past 40 years in the rates of non-communicable diseases associated with obesity and overweight, namely cardiovascular disease. The development of the diet-heart hypothesis in the mid twentieth century led to faulty but long-held beliefs that dietary intake of saturated fat led to heart disease. Saturated fat can lead to increased LDL cholesterol levels, and elevated plasma cholesterol levels have been shown to be a risk factor for cardiovascular disease; however, the correlative nature of their association does not assign causation. Recent findings: Advances in understanding the role of various lipoprotein particles and their atherogenic risk have been helpful for understanding how different dietary components may impact CVD risk. Numerous meta-analyses and systematic reviews of both the historical and current literature reveals that the diet-heart hypothesis was not, and still is not, supported by the evidence. There appears to be no consistent benefit to all-cause or CVD mortality from the reduction of dietary saturated fat. Further, saturated fat has been shown in some cases to have an inverse relationship with obesity-related type 2 diabetes. Rather than focus on a single nutrient, the overall diet quality and elimination of processed foods, including simple carbohydrates, would likely do more to improve CVD and overall health. It is in the best interest of the American public to clarify dietary guidelines to recognize that dietary saturated fat is not the villain we once thought it was.
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Introduction: The consumption of saturated fats is considered a risk factor for cardiovascular diseases. Objective: Review published papers on the role of macro-nutrient intake in cardiovascular risk. Results: Recent reports from the PURE study and several previous metaanalyses, show that the consumption of total saturated and unsaturated fat is not associated with risk of acute myocardial infarction or mortality due to cardiovascular disease. High carbohydrate intake was associated with the highest risk of total and cardiovascular mortality, while total fat consumption or of its different types was associated with a lower risk of mortality. A high consumption of fruits, vegetables and legumes was associated with lower risk of total mortality and non-cardiovascular mortality. The consumption of 100 g of legumes, two or three times a week, ameliorated deficiencies of the nutrients contained in these foods and was associated with a reduction in the risk of developing chronic noncommunicable diseases. Conclusion: A healthy diet should be balanced and varied, be composed of a proportion of complex carbohydrates rich in fibber between 50-55% of the daily energy consumed, of saturated and unsaturated fat (25-30%), animal and vegetable protein (including legumes) between 15-25%, vitamins, minerals and water. These nutrients are abundantly present in fruits, vegetables, cereals, legumes, milk and its derivatives, eggs and meats, so public policies should promote the availability and access to these nutrients within primary prevention programs to reduce the growing prevalence of cardio-metabolic diseases.
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Nutritional research and policies have been criticized for relying on observational evidence, using self-report diet assessment methods, and supposedly being unable to present a consensus on what constitutes a healthy diet. In particular, it is often asserted that for progress to occur in nutrition science, large, simple trials, which have worked well in evaluating the efficacy of drugs, need to replace most observational research and small trials in nutrition. However, this idea is infeasible, and is unlikely to advance nutritional sciences or improve policies. This article addresses some commonly held and unfounded "myths" surrounding dietary assessments, effect sizes, and confounding, demonstrating how carefully conducted observational studies can provide reliable and reproducible evidence on diet and health. Also, there is a strong consensus among nutritional researchers and practitioners about the basic elements of a healthy diet. To move forward, we should continue to improve study design and diet assessment methodologies, reduce measurement errors, and leverage new technologies. Advances in the field lie in coalescing evidence from multiple study designs, methodologies, and technologies, and translating what we already know into policy and practice, so we can improve diet quality and enhance health in an equitable and sustainable manner across the world.
Article
Background and aims: Increased arterial stiffness contributes to diabetic vascular complications. We identified dietary factors related to arterial stiffness in individuals with type 1 diabetes, a population with high risk of cardiovascular disease. Methods and results: Altogether, 612 participants (40% men, mean ± standard deviation age 45 ± 13 years) completed a validated diet questionnaire and underwent measurements of arterial stiffness. Of these, 470 additionally completed a food record. Exploratory factor analysis was applied to identify dietary patterns from the diet questionnaires, and nutrient intakes were calculated from food record entries. Arterial stiffness was measured by applanation tonometry. Of the seven dietary factors formed, the factor scores of "Full-fat cheese and eggs" and "Sweet" patterns were negatively associated with measures of arterial stiffness. In the multivariable macronutrient substitution models, favouring carbohydrates over fats was associated with higher aortic mean arterial pressure and aortic pulse wave velocity. When carbohydrates were consumed in place of proteins, higher aortic pulse pressure, aortic mean arterial pressure, and augmentation index were recorded. Replacing energy from alcohol with proteins, was associated with lower aortic pulse pressure, aortic mean arterial pressure, and augmentation index. Relative distributions of dietary fatty acids were neutral with respect to the measures of arterial stiffness. Conclusion: The macronutrient distribution of the diet is likely to affect the resilience of the arteries. Our observations suggest that reducing energy intake from carbohydrates and alcohol may be beneficial. These observations, especially those dealing with dietary patterns, need to be confirmed in a longitudinal study.
Chapter
Cardiovascular diseases (CVDs) and coronary diseases are leading causes of mortality and morbidity in developed countries. In recent years, although the incidences of these have declined among European countries and United States, it still accounts for almost half (48%) of all deaths in Europe and a third (32.8%) in US. CVD is an inflammatory disease associated with hypercholesterolemia and hypertension. Etiological studies have suggested that modified lipoproteins (e.g., oxidized) present in the arterial subendothelium plays a key role in CVD and coronary heart disease (CHD). Dietary fibers of terrestrial and marine origin are the cornerstones for CVD treatment. Cellulose, hemicellulose, gums, mucilages, pectins, oligosaccharides, lignins, etc. were reported to lower atherogenic lipoprotein levels and degree of oxidation, blood pressure, thrombogenesis, and concentrations of some relevant factors (homocysteine), thus averting CVD and CHD. In this chapter, the emphasis is specified on the therapeutic role of dietary fibers and its components in the prevention of cardiovascular and other relevant diseases. Importance is given to in vitro, in vivo, and clinical studies to bring forth the significance of dietary fibers as a nutraceutical.
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Objective The low-carbohydrate, high-fat (LCHF) diet is becoming increasingly employed in clinical dietetic practice as a means to manage many health-related conditions. Yet, it continues to remain contentious in nutrition circles due to a belief that the diet is devoid of nutrients and concern around its saturated fat content. This work aimed to assess the micronutrient intake of the LCHF diet under two conditions of saturated fat thresholds. Design In this descriptive study, two LCHF meal plans were designed for two hypothetical cases representing the average Australian male and female weight-stable adult. National documented heights, a body mass index of 22.5 to establish weight and a 1.6 activity factor were used to estimate total energy intake using the Schofield equation. Carbohydrate was limited to <130 g, protein was set at 15%–25% of total energy and fat supplied the remaining calories. One version of the diet aligned with the national saturated fat guideline threshold of <10% of total energy and the other included saturated fat ad libitum. Primary outcomes The primary outcomes included all micronutrients, which were assessed using FoodWorks dietary analysis software against national Australian/New Zealand nutrient reference value (NRV) thresholds. Results All of the meal plans exceeded the minimum NRV thresholds, apart from iron in the female meal plans, which achieved 86%–98% of the threshold. Saturated fat intake was logistically unable to be reduced below the 10% threshold for the male plan but exceeded the threshold by 2 g (0.6%). Conclusion Despite macronutrient proportions not aligning with current national dietary guidelines, a well-planned LCHF meal plan can be considered micronutrient replete. This is an important finding for health professionals, consumers and critics of LCHF nutrition, as it dispels the myth that these diets are suboptimal in their micronutrient supply. As with any diet, for optimal nutrient achievement, meals need to be well formulated.
Article
Introduction National dietary guidelines were introduced in 1977 and 1983, by the US and UK governments, with the aim of reducing coronary heart disease (CHD) mortality. The 2 specific dietary fat recommendations were to reduce total fat and saturated fat consumption to 30% and 10% of total energy intake, respectively. Methods 4 systematic reviews (3 with meta-analysis) were undertaken to examine the evidence for these dietary fat guidelines: (1) randomised controlled trial (RCT) and (2) prospective cohort (PC) evidence at the time the guidelines were introduced; and (3) RCT and (4) PC evidence currently available. This narrative review examines all evidence collated. Results The RCT and PC evidence available to the dietary committees did not support the introduction of the dietary fat guidelines. The RCT and PC evidence currently available does not support the extant recommendations. Furthermore, the quality of the evidence is so poor that it could not be relied on had it provided support. Conclusions Dietary fat guidelines have prevailed for almost 40 years. The evidence base at the time of their introduction has been examined for the first time and found lacking. Evidence currently available provides no additional support. Public health opinion differed when the guidelines were introduced. Opposition to the guidelines is becoming more strident. Substantial increases in diet-related illness over the past four decades, particularly obesity and type 2 diabetes, indicate that a review of dietary advice is warranted. © 2016 BMJ Publishing Group Ltd & British Association of Sport and Exercise Medicine.
Article
Introduction National dietary guidelines were introduced in 1977 and 1983, by the US and UK governments, with the aim of reducing coronary heart disease (CHD) mortality. The 2 specific dietary fat recommendations were to reduce total fat and saturated fat consumption to 30% and 10% of total energy intake, respectively. Methods 4 systematic reviews (3 with meta-analysis) were undertaken to examine the evidence for these dietary fat guidelines: (1) randomised controlled trial (RCT) and (2) prospective cohort (PC) evidence at the time the guidelines were introduced; and (3) RCT and (4) PC evidence currently available. This narrative review examines all evidence collated. Results The RCT and PC evidence available to the dietary committees did not support the introduction of the dietary fat guidelines. The RCT and PC evidence currently available does not support the extant recommendations. Furthermore, the quality of the evidence is so poor that it could not be relied on had it provided support. Conclusions Dietary fat guidelines have prevailed for almost 40 years. The evidence base at the time of their introduction has been examined for the first time and found lacking. Evidence currently available provides no additional support. Public health opinion differed when the guidelines were introduced. Opposition to the guidelines is becoming more strident. Substantial increases in diet-related illness over the past four decades, particularly obesity and type 2 diabetes, indicate that a review of dietary advice is warranted.
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Objectives National dietary guidelines were introduced in 1977 and 1983, by the US and UK governments, respectively, with the ambition of reducing coronary heart disease (CHD) by reducing fat intake. To date, no analysis of the evidence base for these recommendations has been undertaken. The present study examines the evidence from randomised controlled trials (RCTs) available to the US and UK regulatory committees at their respective points of implementation. Methods A systematic review and meta-analysis were undertaken of RCTs, published prior to 1983, which examined the relationship between dietary fat, serum cholesterol and the development of CHD. Results 2467 males participated in six dietary trials: five secondary prevention studies and one including healthy participants. There were 370 deaths from all-cause mortality in the intervention and control groups. The risk ratio (RR) from meta-analysis was 0.996 (95% CI 0.865 to 1.147). There were 207 and 216 deaths from CHD in the intervention and control groups, respectively. The RR was 0.989 (95% CI 0.784 to 1.247). There were no differences in all-cause mortality and non-significant differences in CHD mortality, resulting from the dietary interventions. The reductions in mean serum cholesterol levels were significantly higher in the intervention groups; this did not result in significant differences in CHD or all-cause mortality. Government dietary fat recommendations were untested in any trial prior to being introduced. Conclusions Dietary recommendations were introduced for 220 million US and 56 million UK citizens by 1983, in the absence of supporting evidence from RCTs.
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Objective To systematically review associations between intake of saturated fat and trans unsaturated fat and all cause mortality, cardiovascular disease (CVD) and associated mortality, coronary heart disease (CHD) and associated mortality, ischemic stroke, and type 2 diabetes. Design Systematic review and meta-analysis. Data sources Medline, Embase, Cochrane Central Registry of Controlled Trials, Evidence-Based Medicine Reviews, and CINAHL from inception to 1 May 2015, supplemented by bibliographies of retrieved articles and previous reviews. Eligibility criteria for selecting studies Observational studies reporting associations of saturated fat and/or trans unsaturated fat (total, industrially manufactured, or from ruminant animals) with all cause mortality, CHD/CVD mortality, total CHD, ischemic stroke, or type 2 diabetes. Data extraction and synthesis Two reviewers independently extracted data and assessed study risks of bias. Multivariable relative risks were pooled. Heterogeneity was assessed and quantified. Potential publication bias was assessed and subgroup analyses were undertaken. The GRADE approach was used to evaluate quality of evidence and certainty of conclusions. Results For saturated fat, three to 12 prospective cohort studies for each association were pooled (five to 17 comparisons with 90 501-339 090 participants). Saturated fat intake was not associated with all cause mortality (relative risk 0.99, 95% confidence interval 0.91 to 1.09), CVD mortality (0.97, 0.84 to 1.12), total CHD (1.06, 0.95 to 1.17), ischemic stroke (1.02, 0.90 to 1.15), or type 2 diabetes (0.95, 0.88 to 1.03). There was no convincing lack of association between saturated fat and CHD mortality (1.15, 0.97 to 1.36; P=0.10). For trans fats, one to six prospective cohort studies for each association were pooled (two to seven comparisons with 12 942-230 135 participants). Total trans fat intake was associated with all cause mortality (1.34, 1.16 to 1.56), CHD mortality (1.28, 1.09 to 1.50), and total CHD (1.21, 1.10 to 1.33) but not ischemic stroke (1.07, 0.88 to 1.28) or type 2 diabetes (1.10, 0.95 to 1.27). Industrial, but not ruminant, trans fats were associated with CHD mortality (1.18 (1.04 to 1.33) v 1.01 (0.71 to 1.43)) and CHD (1.42 (1.05 to 1.92) v 0.93 (0.73 to 1.18)). Ruminant trans-palmitoleic acid was inversely associated with type 2 diabetes (0.58, 0.46 to 0.74). The certainty of associations between saturated fat and all outcomes was “very low.” The certainty of associations of trans fat with CHD outcomes was “moderate” and “very low” to “low” for other associations. Conclusions Saturated fats are not associated with all cause mortality, CVD, CHD, ischemic stroke, or type 2 diabetes, but the evidence is heterogeneous with methodological limitations. Trans fats are associated with all cause mortality, total CHD, and CHD mortality, probably because of higher levels of intake of industrial trans fats than ruminant trans fats. Dietary guidelines must carefully consider the health effects of recommendations for alternative macronutrients to replace trans fats and saturated fats.
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The Scientific Report of the 2015 Dietary Guidelines Advisory Committee was primarily informed by memory-based dietary assessment methods (M-BMs) (eg, interviews and surveys). The reliance on M-BMs to inform dietary policy continues despite decades of unequivocal evidence that M-BM data bear little relation to actual energy and nutrient consumption. Data from M-BMs are defended as valid and valuable despite no empirical support and no examination of the foundational assumptions regarding the validity of human memory and retrospective recall in dietary assessment. We assert that uncritical faith in the validity and value of M-BMs has wasted substantial resources and constitutes the greatest impediment to scientific progress in obesity and nutrition research. Herein, we present evidence that M-BMs are fundamentally and fatally flawed owing to well-established scientific facts and analytic truths. First, the assumption that human memory can provide accurate or precise reproductions of past ingestive behavior is indisputably false. Second, M-BMs require participants to submit to protocols that mimic procedures known to induce false recall. Third, the subjective (ie, not publicly accessible) mental phenomena (ie, memories) from which M-BM data are derived cannot be independently observed, quantified, or falsified; as such, these data are pseudoscientific and inadmissible in scientific research. Fourth, the failure to objectively measure physical activity in analyses renders inferences regarding diet-health relationships equivocal. Given the overwhelming evidence in support of our position, we conclude that M-BM data cannot be used to inform national dietary guidelines and that the continued funding of M-BMs constitutes an unscientific and major misuse of research resources. Copyright © 2015 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.
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Background: Since 1984 UK citizens have been advised to reduce total dietary fat intake to 30% of total energy and saturated fat intake to 10%. The National Institute of Clinical Excellence [NICE] suggests a further benefit for Coronary Heart Disease [CHD] prevention by reducing saturated fat [SFA] intake to 6% -7% of total energy and that 30,000 lives could be saved by replacing SFAs with Polyunsaturated fats [PUFAs]. Methods: 20 volumes of the Seven Countries Study, the seminal work behind the 1984 nutritional guidelines, were assessed. The evidence upon which the NICE guidance was based was reviewed. Nutritional facts about fat and the UK intake of fat are presented and the impact of macronutrient confusion on public health dietary advice is discussed. Findings: The Seven Countries study classified processed foods, primarily carbohydrates, as saturated fats. The UK government and NICE do the same, listing biscuits, cakes, pastries and savoury snacks as saturated fats. Processed foods should be the target of public health advice but not natural fats, in which the UK diet is deficient. With reference to the macro and micro nutrient composition of meat, fish, eggs, and dairy foods the article demonstrates that dietary trials cannot change one type of fat for another in a controlled study. Interpretation: The evidence suggests that processed food is strongly associated with the increase in obesity, diabetes, CHD, and other modern illness in our society. The macro and micro nutrients found in meat, fish, eggs and dairy products, are vital for human health and consumption of these nutritious foods should be encouraged.
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Background: A reduction in dietary saturated fat has generally been thought to improve cardiovascular health. Objective: The objective of this meta-analysis was to summarize the evidence related to the association of dietary saturated fat with risk of coronary heart disease (CHD), stroke, and cardiovascular disease (CVD; CHD inclusive of stroke) in prospective epidemiologic studies. Design: Twenty-one studies identified by searching MEDLINE and EMBASE databases and secondary referencing qualified for inclusion in this study. A random-effects model was used to derive composite relative risk estimates for CHD, stroke, and CVD. Results: During 5-23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD. The pooled relative risk estimates that compared extreme quantiles of saturated fat intake were 1.07 (95% CI: 0.96, 1.19; P = 0.22) for CHD, 0.81 (95% CI: 0.62, 1.05; P = 0.11) for stroke, and 1.00 (95% CI: 0.89, 1.11; P = 0.95) for CVD. Consideration of age, sex, and study quality did not change the results. Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.
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Because of the pressure for timely, informed decisions in public health and clinical practice and the explosion of information in the scientific literature, research results must be synthesized. Meta-analyses are increasingly used to address this problem, and they often evaluate observational studies. A workshop was held in Atlanta, Ga, in April 1997, to examine the reporting of meta-analyses of observational studies and to make recommendations to aid authors, reviewers, editors, and readers. Twenty-seven participants were selected by a steering committee, based on expertise in clinical practice, trials, statistics, epidemiology, social sciences, and biomedical editing. Deliberations of the workshop were open to other interested scientists. Funding for this activity was provided by the Centers for Disease Control and Prevention. We conducted a systematic review of the published literature on the conduct and reporting of meta-analyses in observational studies using MEDLINE, Educational Research Information Center (ERIC), PsycLIT, and the Current Index to Statistics. We also examined reference lists of the 32 studies retrieved and contacted experts in the field. Participants were assigned to small-group discussions on the subjects of bias, searching and abstracting, heterogeneity, study categorization, and statistical methods. From the material presented at the workshop, the authors developed a checklist summarizing recommendations for reporting meta-analyses of observational studies. The checklist and supporting evidence were circulated to all conference attendees and additional experts. All suggestions for revisions were addressed. The proposed checklist contains specifications for reporting of meta-analyses of observational studies in epidemiology, including background, search strategy, methods, results, discussion, and conclusion. Use of the checklist should improve the usefulness of meta-analyses for authors, reviewers, editors, readers, and decision makers. An evaluation plan is suggested and research areas are explored.
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Dietary guidelines generally recommend avoiding a high-fat diet. However, the relationship between fat subtypes and mortality remains unclear especially in a population with a relatively low intake of fat. We aimed to prospectively examine the relationship between dietary fat intake and all-cause and cause-specific mortality in a Japanese community. In 1992, a total of 28,356 residents of Takayama, Japan, without cancer, stroke, or coronary heart disease, responded to a validated 169-item FFQ. We identified 4616 deaths during a 16-y follow-up. The HR of mortality according to the percentage of energy from the total and subtypes of fat when substituted for an isoenergic quantity of carbohydrate was calculated after controlling for potential confounders. A high intake of total fat and PUFA was associated with a decrease in all-cause mortality in men; the HR for the highest compared with the lowest quintile were 0.83 (95% CI: 0.70, 0.99; P-trend = 0.048) for total fat and 0.77 (95% CI: 0.62, 0.95; P-trend = 0.05) for PUFA. Both fats were associated with a decrease in mortality from cancer and diseases other than cardiovascular disease. In women, a higher SFA intake was associated with higher all-cause mortality [HR = 1.22 (95% CI: 0.99, 1.49; P-trend = 0.03)]. A favorable effect was suggested for total fat and PUFA intakes on mortality in men except for that from cardiovascular disease, whereas increased SFA intake may be associated with adverse health consequences in women.
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Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
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David Moher and colleagues introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses
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Observational studies constitute an important category of study designs. To address some investigative questions in plastic surgery, randomized controlled trials are not always indicated or ethical to conduct. Instead, observational studies may be the next best method of addressing these types of questions. Well-designed observational studies have been shown to provide results similar to those of randomized controlled trials, challenging the belief that observational studies are second rate. Cohort studies and case-control studies are two primary types of observational studies that aid in evaluating associations between diseases and exposures. In this review article, the authors describe these study designs and methodologic issues, and provide examples from the plastic surgery literature.
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Over 10,000 male civil servants and municipal employees in Israel, aged 40 years and above, underwent an extensive clinical, biochemical, anthropometric, sociodemographic and psychosocial evaluation in 1963, 1965 and 1968. Follow-up for mortality was continued through 1986. Over 23 years, a number of previously established risk factors for coronary heart disease (CHD) incidence were found to predict mortality. The long-term follow-up assisted in illustrating temporal patterns. A single causal assessment of blood pressure retained high prediction for long-term mortality. Blood lipids, while significantly associated with both coronary and all-cause mortality, exhibited a small contribution to the latter, when compared to hypertension, cigarette smoking habits and diabetes. Weak associations of long-term coronary mortality with the dietary intake patterns of fatty acids, as reported at baseline, were probably fully mediated by the effect of the diet on serum cholesterol. Religious orthodoxy appeared to provide a degree of immunity, part of which was independent of life-style correlates. A number of now well-established associations in cardiovascular epidemiology were first demonstrated, or amplified, in the study. Patterns of ethnic diversity in the risk factor and prevalence rates of CHD persisted, as viewed from the angle of mortality rates, over nearly a quarter of a decade, highlighting the enigma of a migrant country as a cardiovascular melting pot.
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The Caerphilly Prospective Ischaemic Heart Disease (IHD) Study is based on a sample of 2512 men aged 45-59 years when first seen. Nutrient intakes, estimated using a self-administered semi-quantitative food frequency questionnaire, are available for 2423 men (96%). Amongst these, 148 major IHD events occurred during the first 5 years of follow-up. Associations were examined between these events and baseline diet. Incident IHD (new events) was negatively associated with total energy intake: men who went on to experience an IHD event had consumed 560 kJ (134 kcal)/d (6%) less at baseline than men who experienced no event (P = 0.01). The relative odds of an IHD event was 1.5 among men in the lowest fifth of energy intake, compared with 1.3, 1.2, 0.9 and 1.0 respectively for the other four fifths (P < 0.05). The difference in energy intake was reflected in lower intakes of every nutrient examined. When expressed as a percentage of total energy, mean intakes of men who experienced an IHD event were virtually identical to those of men who did not. There was some evidence suggesting a positive association between total fat intake and IHD risk, but the trend was not consistent and not statistically significant. There was no association for animal fat. Alcohol consumption was negatively associated with subsequent IHD, but only in men who already had evidence of IHD at baseline (P < 0.05). Dietary fibre, particularly from fruit and vegetables, was 7% lower in men who had an incident IHD event (P < 0.05), but the difference was not independent of total energy. There was a trend of increasing IHD risk with decreasing vitamin C intake, the relative odds of an IHD event being 1.6 among men in the lowest one-fifth of the vitamin C distribution, but this was not statistically significant.
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The relation of intakes of specific fatty acids and the risk of coronary heart disease was examined in a cohort of 21,930 smoking men aged 50-69 years who were initially free of diagnosed cardiovascular disease. All men participated in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and completed a detailed and validated dietary questionnaire at baseline. After 6.1 years of follow-up from 1985-1988, the authors documented 1,399 major coronary events and 635 coronary deaths. After controlling for age, supplement group, several coronary risk factors, total energy, and fiber intake, the authors observed a significant positive association between the intake of trans-fatty acids and the risk of coronary death. For men in the top quintile of trans-fatty acid intake (median = 6.2 g/day), the multivariate relative risk of coronary death was 1.39 (95% confidence interval (CI) 1.09-1.78) (p for trend = 0.004) as compared with men in the lowest quintile of intake (median = 1.3 g/day). The intake of omega-3 fatty acids from fish was also directly related to the risk of coronary death in the multivariate model adjusting also for trans-saturated and cis-monounsaturated fatty acids (relative risk (RR) = 1.30, 95% CI 1.01-1.67) (p for trend = 0.06 for men in the highest quintile of intake compared with the lowest). There was no association between intakes of saturated or cis-monounsaturated fatty acids, linoleic or linolenic acid, or dietary cholesterol and the risk of coronary deaths. All the associations were similar but somewhat weaker for all major coronary events.
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To investigate the prevalence and nature of low energy reporting in a dietary survey of British adults over 65 years of age. Randomly selected cross sectional sample of 2060 British adults over 65 years. Four day weighed food diaries and questionnaires on health, lifestyle and socioeconomic characteristics. Great Britain. 539 women and 558 men over 65 years who were free living and completed four day food diaries. A high proportion of men and women were classified as low energy reporters (LERs). Reported consumption of full fat dairy products, sugar and sweet foods, and alcoholic drinks differed most between LERs and non-LERs. Among LERs, reported protein and starch intakes were higher, fat, sugar and alcohol intakes were lower. LERs of either sex were more likely to be obese, male LERs were also more likely to belong to the manual social classes. The high level of low energy reporting probably resulted from a coalescence of factors such as the weighed diary methodology and a reluctance to report consumption of unhealthy foods. The use of validatory biomarkers such as doubly labelled water needs to be more widespread.
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A common question in clinical consultations is: “For this person, what are the likely effects of one treatment compared with another?” The central tenet of evidence based medicine is that this task is achieved by using the best evidence combined with consideration of that person's individual needs.1 A further question then arises: “What is the best evidence?” Two recent studies in the New England Journal of Medicine have caused uproar in the research community by finding no difference in estimates of treatment effects between randomised controlled trials and non-randomised trials.The randomised controlled trial and, especially, systematic reviews of several of these trials are traditionally the gold standards for judging the benefits of treatments, mainly because it is conceptually easier to attribute any observed effect to the treatments being compared. The role of non-randomised (observational) studies in evaluating treatments is contentious: deliberate choice of the treatment for each person implies that observed outcomes may be caused by differences among people being given the two treatments, rather than the treatments alone. Unrecognised confounding factors can always interfere with attempts to correct for identified differences between groups.These considerations have supported a hierarchy of evidence, with randomised controlled trials and derivatives at the top, controlled …
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Objectives National dietary guidelines were introduced in 1977 and 1983, by the USA and UK governments, respectively, with the ambition of reducing coronary heart disease (CHD) mortality by reducing dietary fat intake. A recent systematic review and meta-analysis by the present authors, examining the randomised controlled trial (RCT) evidence available to the dietary committees during those time periods, found no support for the recommendations to restrict dietary fat. The present investigation extends our work by re-examining the totality of RCT evidence relating to the current dietary fat guidelines. Methods A systematic review and meta-analysis of RCTs currently available, which examined the relationship between dietary fat, serum cholesterol and the development of CHD, was undertaken. Results The systematic review included 62 421 participants in 10 dietary trials: 7 secondary prevention studies, 1 primary prevention and 2 combined. The death rates for all-cause mortality were 6.45% and 6.06% in the intervention and control groups, respectively. The risk ratio (RR) from meta-analysis was 0.991 (95% CI 0.935 to 1.051). The death rates for CHD mortality were 2.16% and 1.80% in the intervention and control groups, respectively. The RR was 0.976 (95% CI 0.878 to 1.084). Mean serum cholesterol levels decreased in all intervention groups and all but one control group. The reductions in mean serum cholesterol levels were significantly greater in the intervention groups; this did not result in significant differences in CHD or all-cause mortality. Conclusions The current available evidence found no significant difference in all-cause mortality or CHD mortality, resulting from the dietary fat interventions. RCT evidence currently available does not support the current dietary fat guidelines. The evidence per se lacks generalisability for population-wide guidelines.
Article
Objectives National dietary guidelines were introduced in 1977 and 1983, by the USA and UK governments to reduce coronary heart disease (CHD) mortality by reducing dietary fat intake. Our 2015 systematic review examined randomised controlled trial (RCT) evidence available to the dietary committees at the time; we found no support for the recommendations to restrict dietary fat. What epidemiological evidence was available to the dietary guideline committees in 1983? Methods A systematic review of prospective cohort studies, published prior to 1983, which examined the relationship between dietary fat, serum cholesterol and the development of CHD. Results Across 6 studies, involving 31 445 participants, there were 1521 deaths from all-causes and 360 deaths from CHD during the mean follow-up of 7.5±6.2 years. The death rates were 4.8% and 1.1% from all-causes and CHD respectively. One study included men with previous heart disease. The death rate from CHD for those with, and without previous myocardial infarction was 20.9% and 1.0% respectively. None of the six studies found a significant relationship between CHD deaths and total dietary fat intake. One of the six studies found a correlation between CHD deaths and saturated dietary fat intake across countries; none found a relationship between CHD deaths and saturated dietary fat in the same population. Conclusions 1983 dietary recommendations for 220 million US and 56 million UK citizens lacked supporting evidence from RCT or prospective cohort studies. The extant research had been undertaken exclusively on males, so lacked generalisability for population-wide guidelines.
Coronary heart disease (CHD) remains as the main cause of death in most countries of the world including Puerto Rico. Due to the importance of gathering knowledge regarding the harmful effects and risk factors associated with the development of CHD some basic information is reviewed to stimulate the institution of measures for reduction of the prevalence of clinical CHD and its ultimate consequences. Special attention is given in the manuscript of the Puerto Rico Heart Health Program conducted in men aged 45-64 residing in four rural and three urban areas. The Puerto Rico and the Honolulu Study confirmed the initial publication on the epidemiology of coronary heart disease by the Framingham study. The presentation of some data collected among the three studies strengthen the message of avoiding the development of CHD by installing preventive measures for control and reduction of the risk factors. Concurrent data obtained in the three studies is presented. Although the degree of the involvement of the populations is higher in Framingham than in Puerto Rico and Honolulu, the deleterious effects of specific risk factors are harmful in all the three populations. Difference in the prevalence of risk factors among the urban and rural males in Puerto Rico is also illustrated. It is our hope that more intense measures be instituted in Puerto Rico at all levels in order to control risk factors and reduce the incidence of coronary disease in Puerto Rico.
Article
Sixteen cohorts of men aged 40–59 years at entry were examined with the measurement of some risk factors and then followed-up for mortality and causes of death for 25 years. These cohorts were located in the USA (1 cohort), Finland (2), the Netherlands (1), Italy (3), the former Yugoslavia (5), Greece (2), and Japan (2), and included a total of 12,763 subjects.Large differences in age-adjusted coronary heart disease (CHD) death rates were found, with extremes of 45 per 1000 in 25 years in Tanushimaru, Japan, to 288 per 1000 in 25 years in East Finland. In general, higher rates were found in the US and Northern European cohorts as compared to the Southern European and Japanese cohorts. However, during the last 10 years of follow-up large increases of CHD death rates were found in some Yugoslavian areas. Out of 5 measured entry characteristics treated as age-adjusted levels (serum cholesterol, systolic blood pressure, cigarette smoking, body mass index and physical activity at work), only serum cholesterol was significant in explaining cohort differences in CHD death rates.Over 50% of the variance in CHD death rates in 25 years was accounted for by the difference in mean serum cholesterol. This association tended to decline with increasing length of follow-up, but this was due to the great changes in mean serum cholesterol in the two Jugoslavian cohorts of Velika Krsna and Zrenjanin. When these two cohorts were excluded the association increased with time.Changes in mean serum cholesterol between year 0 and 10 helped in explaining differences in CHD death rates from year 10 onward.It can be concluded that this study suggests that mean serum cholesterol is the major risk factor in explaining cross-cultural differences in CHD.
Article
McGee, D. L. (Framingham Heart Study, Framingham, MA 01701), D. M. Reed, K. Yano, A. Kagan and J. Tillotson. Ten-year incidence of coronary heart disease in the Honolulu Heart Program: relationship to nutrient intake. Am J Epidemiol 1984; 119: 667–76. Nutrient intake was determined in over 8000 men of Japanese ancestry residing on the island of Oahu. Nutrient determination took place at the initial examination during the years 1965–1968. This report relates nutrient intake to the risk of developing coronary heart disease in the 10 years subsequent to the initial examination. Men who developed coronary heart disease had a lower average intake of calories, carbohydrates, starch, and vegetable protein than men who remained free of coronary heart disease. Men who developed coronary heart disease also had a higher mean intake of percentage of calories from protein, fat, saturated fatty acids, and polyunsaturated fatty acids than men who remained free of coronary heart disease. These men also had a significantly lower mean percentage of calories from carbohydrates and a higher mean ingestion of cholesterol per 1000 calories than men who remained free of coronary heart disease. In multivariate analyses including age, systolic blood pressure, serum cholesterol, cigarettes smoked per day, and physical activity index, carbohydrates, vegetable protein, percentage of calories from saturated fatty acids, and percentage of calories from polyunsaturated fatty acids are no longer significantly related to incidence.
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The British Isles have a very cloudy climate and as a result receive fewer hours of clear sunlight than most other industrial regions. The majority of people in these islands have low blood levels of vitamin D [25(OH)D] all year round. Few food products are fortified with vitamin D in the UK and the government does not recommend any vitamin D supplement for most adults in the UK. Diseases associated with vitamin D insufficiency such as cancer, heart disease, diabetes (types 1 and 2) and multiple sclerosis are more frequent in the UK, and particularly in Scotland, than in many other European countries and some, such as multiple sclerosis and diabetes (types 1 and 2), are increasing in incidence. Present knowledge suggests that the risk of some chronic diseases could be reduced if vitamin D intake or sun exposure of the population were increased. Yet policy and public health recommendations of the UK government and its agencies (e.g. the Health Protection Agency, the Food Standards Agency) and of Cancer Research UK have failed to take full account of established and putative benefits of vitamin D and/or sunshine. The epidemic of chronic disease in the UK, which is associated with and caused at least in part by vitamin D insufficiency, has not been adequately recognized by these agencies, and too often measures taken by them have been misguided, inappropriate or ineffective.
Article
A controlled intervention trial, with the purpose of testing the hypothesis that the incidence of coronary heart disease (CHD) could be decreased by the use of serum-cholesterol-lowering (SCL) diet, was carried out in 2 mental hospitals near Helsinki in 1959--71. The subjects were hospitalized middle-aged men. One of the hospitals received the SCL diet, i.e. a diet low in saturated fats and cholesterol and relatively high in polyunsaturated fats, while the other served as the control with a normal hospital diet. Six years later the diets were reversed, and the trial was continued another 6 years. The use of the SCL diet was associated with markedly lowered serum-cholesterol values. The incidence of CHD, as measured by the appearance of certain electrocardiographic patterns and by the occurrence of coronary deaths, was in both hospitals during the SCL-diet periods about half that during the normal-diet periods. An examination of a number of potential confounding variables indicated that the changes in them were small and failed to account for the considerable reduction in the incidence of CHD. It is concluded that the use of the serum-cholesterol-lowering diet exerted a substantial preventive effect on CHD.
Article
During 1956-66, 337 healthy middle-aged men in London and south-east England participated in a seven-day individual weighed dietary survey. By the end of 1976, 45 of them had developed clinical coronary heart disease (CHD) which showed two main relationships with diet. Men with a high energy intake had a lower rate of disease than the rest, and, independently of this, so did men with a high intake of dietary fibre from cereals. Energy intake reflects physical activity, but the advantage of a diet high in cereal fibre cannot be explained; there was no evidence that the disease was associated with consumption of refined carbohydrates. Fewer cases of CHD developed among men with a relatively high ratio of polyunsaturated to saturated fatty acids in their diet, but the difference was not statistically significant.
Article
The relationship of dietary intakes to subsequent development of coronary heart disease (CHD) during a 6-year follow-up period was investigated in 7705 men of Japanese ancestry, ages 45 to 68 and living in Hawaii. Data on the intakes of calories and nutrients were obtained by 24-hr diet recall interviews at the base-line examination. An index for ingestion of traditional Japanese diet (Japanese diet score) was also calculated for each man. The men who subsequently developed myocardial infarction or died of CHD generally ate less than those who remained free of CHD, with statistically significant differences for total calories, total carbohydrate, complex carbohydrate or starch, simple carbohydrate other than sucrose, vegetable protein, alcohol, and Japanese diet score. However, when other major risk factors for CHD were taken into account, the negative association with CHD remained statistically significant only for alcohol and, to a lesser extent, total carbohydrate intakes. The lower total caloric intakes in CHD cases, largely due to decreased alcohol and carbohydrate intakes, could not be accounted for by either under-reporting of food consumption among obese men or diminished physical activity in CHD cases.
Article
Dietary intake information was collected on 2,426 rural and 5,828 urban men free of coronary heart disease in the Pureto Rico Heart Health Program. Serum cholesterol and triglyceride, body weights, and related parameters were measured during a detailed cardiovascular examination. There were statistically significant differences between rural and urban values with respect to lipids, relative weight, and intake of many nutrients. Rural subjects had lower lipids and relative weights. Serum cholesterol was associated with relative weight in both rural and urban areas. In the urban areas, serum cholesterol was associated with intake of total fat, saturated fatty acids, polyunsaturated fatty acids, total carbohydrate, and starch (all measured as percent of calories). It was also related to percent carbohydrate from starch and dietary cholesterol intake, even after relative weight was taken into account. The associations were of a low order, although statistically significant. The association of fasting triglycerides with some of the carbohydrate variables was statistically significant after relative weight was taken into account in the urban area. Overall, diet and relative weight can account for at most 6% of the variability in serum cholesterol observed, with at most 2.5% of the variability due diet alone.
Article
The relationship between dietary lipids and the 16-year incidence of coronary heart disease (CHD) morbidity and mortality was examined in two male cohorts, aged 45 to 55 years (n = 420) and 56 to 65 years (n = 393) from the Framingham Study. Dietary lipids were assessed through a single 24-hour recall at the initiation of follow-up in 1966 to 1969. In the younger cohort, there were significant positive associations between the incidence of CHD and the proportion of dietary energy intake from total fat and monounsaturated fatty acids. The proportion of energy intake from saturated fatty acids had a marginally significant positive association with CHD. The associations remained even after adjustment for cardiovascular disease risk factors, including serum cholesterol level, suggesting that their effects are at least partially independent of other established risk factors. In contrast to the younger cohort, none of the dietary lipids were associated with CHD in the older cohort. Dietary intervention for the prevention of CHD in younger men is supported by these findings.
Article
The Minnesota Coronary Survey was a 4.5-year, open enrollment, single end-time double-blind, randomized clinical trial that was conducted in six Minnesota state mental hospitals and one nursing home. It involved 4393 institutionalized men and 4664 institutionalized women. The trial compared the effects of a 39% fat control diet (18% saturated fat, 5% polyunsaturated fat, 16% monounsaturated fat, 446 mg dietary cholesterol per day) with a 38% fat treatment diet (9% saturated fat, 15% polyunsaturated fat, 14% monounsaturated fat, 166 mg dietary cholesterol per day) on serum cholesterol levels and the incidence of myocardial infarctions, sudden deaths, and all-cause mortality. The mean duration of time on the diets was 384 days, with 1568 subjects consuming the diet for over 2 years. The mean serum cholesterol level in the pre-admission period was 207 mg/dl, falling to 175 mg/dl in the treatment group and 203 mg/dl in the control group. For the entire study population, no differences between the treatment and control groups were observed for cardiovascular events, cardiovascular deaths, or total mortality. A favorable trend for all these end-points occurred in some younger age groups.
Article
In a prospective epidemiologic study of 1001 middle-aged men, we examined the relation between dietary information collected approximately 20 years ago and subsequent mortality from coronary heart disease. The men were initially enrolled in three cohorts: one of men born and living in Ireland, another of those born in Ireland who had emigrated to Boston, and the third of those born in the Boston area of Irish immigrants. There were no differences in mortality from coronary heart disease among the three cohorts. In within-population analyses, those who died of coronary heart disease had higher Keys (P = 0.06) and modified Hegsted (P = 0.02) dietary scores than did those who did not (a high score indicates a high intake of saturated fatty acids and cholesterol and a relatively low intake of polyunsaturated fatty acids). These associations were significant (P = 0.03 for the Keys and P = 0.04 for the modified Hegsted scores) after adjustment for other risk factors for coronary heart disease. Fiber intake (P = 0.04) and a vegetable-foods score, which rose with increased intake of fiber, vegetable protein, and starch (P = 0.02), were lower among those who died from coronary heart disease, though not significantly so after adjustment for other risk factors. A higher Keys score carried an increased risk of coronary heart disease (relative risk, 1.60), and a higher fiber intake carried a decreased risk (relative risk, 0.57). Overall, these results tend to support the hypothesis that diet is related, albeit weakly, to the development of coronary heart disease.
Article
A controlled intervention trial, with the purpose of testing the hypothesis that the incidence of coronary heart disease (CHD) could be decreased by the use of a serum-cholesterol-lowering (SCL) diet, was carried out in two mental hospitals near Helsinki in 1959-71. The subjects were hospitalized middle-aged women. One of the hospitals received the SCL diet, ie a diet low in saturated fats and cholesterol and relatively high in poly-unsaturated fats, while the other served as the control with a normal hospital diet. Six years later the diets were reversed, and the trial was continued another six years. The use of the SCL diet was associated with markedly lowered serum cholesterol values. The incidence of CHD, as measured by the appearance of certain electrocardiographic patterns and by the occurrence of coronary deaths, was in both hospitals during the SCL-diet periods lower than during the normal-diet periods. The differences, however, failed to reach statistical significance. An examination of a number of potential confounding variables indicated that the changes in them were small and failed to account for the reduction in the incidence of CHD. Although the results of this trial do not permit firm conclusions, they support the idea that also among female populations the SCL diet exerts a preventive effect on CHD.
Article
Beaton et al (Am J Clin Nutr 1979;32:2546-59) reported on the partitioning of variance in 1-day dietary data for the intake of energy, protein, total carbohydrate, total fat, classes of fatty acids, cholesterol, and alcohol. Using the same food intake data and the expanded National Heart, Lung and Blood Institute food composition data base, these analyses of sources of variance have been expanded to include classes of carbohydrate, vitamin A, vitamin C, thiamin, riboflavin, niacin, calcium, iron, total ash, caffeine, and crude fiber. The analyses relate to observed intakes (replicated six times) of 30 adult males and 30 adult females obtained under a paired Graeco-Latin square design with sequence of interview, interviewer, and day of the week as determinants. Neither sequence nor interviewer made consistent contribution to variance. In females, day of the week had a significant effect for several nutrients. The major partitioning of variance was between interindividual variation (between subjects) and intraindividual variation (within subjects) which included both true day-to-day variation in intake and methodological variation. For all except caffeine, the intraindividual variability of 1-day data was larger than the interindividual variability. For vitamin A, almost all of the variance was associated with day-to-day variability. One day data provide a very inadequate estimate of usual intake of individuals. In the design of nutrition studies it is critical that the intended use of dietary data be a major consideration in deciding on methodology. There is no "ideal" dietary method. There may be preferred methods for particular purposes.
Article
Previous studies suggested that cardiovascular disease (CVD) seasonality is due to variations in temperature or respiratory disease prevalence. Another mechanism might be that the seasonal variation in ultra-violet (UV) radiation is responsible for the seasonality of CVD. An hypothesis is put forward that UV radiation, by increasing body levels of vitamin D, protects against CVD by decreasing the risk of thrombus formation. This hypothesis might explain the seasonal variations in CVD mortality and morbidity which decrease in summer, the higher CVD mortality in higher latitudes, and the inverse relationship between altitude and CVD mortality. It is speculated that this mechanism might involve a direct effect of vitamin D on the platelet, or might be mediated by a change in calcium metabolism.
Article
Over twenty years ago, we evaluated diet, serum cholesterol, and other variables in 1900 middle-aged men and repeated the evaluation one year later. No therapeutic suggestions were made. Vital status was determined at the 20th anniversary of the initial examination. Scores summarizing each participant's dietary intake of cholesterol, saturated fatty acids, and polyunsaturated fatty acids were calculated according to the formulas of Keys and Hegsted and their co-workers. The two scores were highly correlated, and results were similar for both: there was a positive association between diet score and serum cholesterol concentration at the initial examination, a positive association between change in diet score and change in serum cholesterol concentration from the initial to the second examination, and a positive association prospectively between mean base-line diet score and the 19-year risk of death from coronary heart disease. These associations persisted after adjustment for potentially confounding factors. The results support the conclusion that lipid composition of the diet affects serum cholesterol concentration and risk of coronary death in middle-aged American men.
Article
Baseline 24-hour dietary recalls from 16,349 men ages 45-64 years who had no evidence of coronary heart disease (CHD) were obtained in three prospective studies: the Framingham Study (859 men), the Honolulu Heart Study (7272 men) and the Puerto Rico Heart Health Program (8218 men). These men were followed for up to 6 years for the first appearance of CHD or death. Men who had a greater caloric intake or a greater caloric intake per kilogram of body weight were less likely to develop CHD manifest as myocardial infarction (MI) or CHD death, even though men of greater weight were more likely to develop CHD. This may reflect the benefit of greater physical activity. Men who consumed more alcohol were less likely to develop CHD, but more likely to die of causes other than CHD, particularly in the Honolulu study. In the Honolulu and Puerto Rico studies, but not in the Framingham study, men who consumed more starch were less likely to develop MI or CHD death. There was an inverse relation between starch intake and serum cholesterol, but it was too weak to explain fully the inverse starch-CHD association. There was also no evidence that the inverse relation between starch intake and incidence of CHD in the Honolulu and Puerto Rico studies was an indirect result of differences in fat intake. While the findings suggest additional areas for research, none of them would lead to an alteration of currently recommended preventive diets that emphasize lowering fat intake, because in isocaloric diets the logical way to balance a decreased fat intake is to increase the consumption of foods containing starch.
Article
The diet-heart hypothesis proposes that elevated intakes of total fat, saturated fat, and dietary cholesterol raise serum cholesterol, which in turn increases the risk of developing coronary heart disease (CHD). To examine the relationship between dietary intake and 12-year CHD mortality we used data from the Lipid Research Clinics Prevalence Follow-Up Study. Dietary intake was measured at study entry using the 24-hour recall technique among 4546 North American men and women who were at least 30 years old and initially free of CHD. Proportional hazards analyses controlling for total energy intake indicated that increasing percentages of energy intake as total fat (RR 1.04, 95% CI = 1.01-1.08), saturated fat (RR 1.11, CI = 1.04-1.18), and monounsaturated fat (RR 1.08, CI = 1.01-1.16) were significant risk factors for CHD mortality among 30 to 59 year olds. The increasing percentage of energy intake from carbohydrate had a significant protective effect (RR 0.96, CI = 0.94-0.99). The strength of these associations was not diminished after adjustment for specific serum lipids, suggesting that serum lipids did not mediate the effect of diet on CHD mortality. None of the dietary components were significantly associated with CHD mortality among those aged 60-79 years. We conclude that future research must be directed toward better understanding the pathway between dietary intake and coronary disease as the current diet-lipid-heart hypothesis may be overly simplistic.
Article
To examine the association between fat intake and the incidence of coronary heart disease in men of middle age and older. Cohort questionnaire study of men followed up for six years from 1986. The health professionals follow up study in the United States. 43 757 health professionals aged 40 to 75 years free of diagnosed cardiovascular disease or diabetes in 1986. Incidence of acute myocardial infarction or coronary death. During follow up 734 coronary events were documented, including 505 non-fatal myocardial infarctions and 229 deaths. After age and several coronary risk factors were controlled for significant positive associations were observed between intake of saturated fat and risk of coronary disease. For men in the top versus the lowest fifth of saturated fat intake (median = 14.8% v 5.7% of energy) the multivariate relative risk for myocardial infarction was 1.22 (95% confidence interval 0.96 to 1.56) and for fatal coronary heart disease was 2.21 (1.38 to 3.54). After adjustment for intake of fibre the risks were 0.96 (0.73 to 1.27) and 1.72 (1.01 to 2.90), respectively. Positive associations between intake of cholesterol and risk of coronary heart disease were similarly attenuated after adjustment for fibre intake. Intake of linolenic acid was inversely associated with risk of myocardial infarction; this association became significant only after adjustment for non-dietary risk factors and was strengthened after adjustment for total fat intake (relative risk 0.41 for a 1% increase in energy, P for trend < 0.01). These data do not support the strong association between intake of saturated fat and risk of coronary heart disease suggested by international comparisons. They are compatible, however, with the hypotheses that saturated fat and cholesterol intakes affect the risk of coronary heart disease as predicted by their effects on blood cholesterol concentration. They also support a specific preventive effect of linolenic acid intake.
Article
To investigate dietary determinants of ischaemic heart disease (IHD) in health conscious individuals to explain the reduced risk in vegetarians, and to examine the relation between IHD and body mass index (BMI) within the normal range. Prospective observation of vegetarians, semi-vegetarians, and meat eaters for whom baseline dietary data, reported weight and height information, social class, and smoking habits were recorded. 10,802 men and women in the UK aged between 16 and 79, mean duration of follow up 13.3 years. Death rate rations for IHD and total mortality in relation to dietary and other characteristics recorded at recruitment (reference category death rate = 100). IHD mortality was less than half that expected from the experience reported for all of England and Wales. An increase in mortality for IHD was observed with increasing intakes of total and saturated animal fat and dietary cholesterol-death rate ratios in the third tertile compared with the first tertile: 329, 95% confidence interval (CI) 150 to 721; 277, 95% CI 125 to 613; 353, 95% CI 157 to 796, respectively. No protective effects were observed for dietary fibre, fish or alcohol. Within the study, death rate ratios were increased among those in the upper half of the normal BMI range (22.5 to < 25) and those who were overweight (BMI > or = 25) compared with those with BMI 20 to < 22.5. In these relatively health conscious individuals the deleterious effects of saturated animal fat and dietary cholesterol appear to be more important in the aetiology of IHD than the protective effect of dietary fibre. Reduced intakes of saturated animal fat and cholesterol may explain the lower rates of IHD among vegetarians compared with meat eaters. Increasing BMI within the normal range is associated with increased risk of IHD. The results have important public health implications.