Meta-analysis of prospective cohort studies evaluating the association of saturated f

[MaxBrenner]

Saturated fat and cardiometabolic risk factors, coronary heart disease, stroke, and diabetes: a fresh look at the evidence. Saturated fat and cardiometabolic risk factors, coron... [Lipids. 2010] - PubMed - NCBI


Micha R, Mozaffarian D.
Source

Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.

Abstract

Dietary and policy recommendations frequently focus on reducing saturated fatty acid consumption for improving cardiometabolic health, based largely on ecologic and animal studies. Recent advances in nutritional science now allow assessment of critical questions about health effects of saturated fatty acids (SFA). We reviewed the evidence from randomized controlled trials (RCTs) of lipid and non-lipid risk factors, prospective cohort studies of disease endpoints, and RCTs of disease endpoints for cardiometabolic effects of SFA consumption in humans, including whether effects vary depending on specific SFA chain-length; on the replacement nutrient; or on disease outcomes evaluated. Compared with carbohydrate, the TC:HDL-C ratio is nonsignificantly affected by consumption of myristic or palmitic acid, is nonsignificantly decreased by stearic acid, and is significantly decreased by lauric acid. However, insufficient evidence exists for different chain-length-specific effects on other risk pathways or, more importantly, disease endpoints. Based on consistent evidence from human studies, replacing SFA with polyunsaturated fat modestly lowers coronary heart disease risk, with ~10% risk reduction for a 5% energy substitution; whereas replacing SFA with carbohydrate has no benefit and replacing SFA with monounsaturated fat has uncertain effects. Evidence for the effects of SFA consumption on vascular function, insulin resistance, diabetes, and stroke is mixed, with many studies showing no clear effects, highlighting a need for further investigation of these endpoints. Public health emphasis on reducing SFA consumption without considering the replacement nutrient or, more importantly, the many other food-based risk factors for cardiometabolic disease is unlikely to produce substantial intended benefits.

 

[MaxBrenner]

Saturated fat, carbohydrate, and cardiovascular disease. Saturated fat, carbohydrate, and cardiovascul... [Am J Clin Nutr. 2010] - PubMed - NCBI


Siri-Tarino PW, Sun Q, Hu FB, Krauss RM.
Source

Department of Atherosclerosis Research Children's Hospital Oakland Research Institute Oakland, CA, USA.

Abstract

A focus of dietary recommendations for cardiovascular disease (CVD) prevention and treatment has been a reduction in saturated fat intake, primarily as a means of lowering LDL-cholesterol concentrations. However, the evidence that supports a reduction in saturated fat intake must be evaluated in the context of replacement by other macronutrients. Clinical trials that replaced saturated fat with polyunsaturated fat have generally shown a reduction in CVD events, although several studies showed no effects. An independent association of saturated fat intake with CVD risk has not been consistently shown in prospective epidemiologic studies, although some have provided evidence of an increased risk in young individuals and in women. Replacement of saturated fat by polyunsaturated or monounsaturated fat lowers both LDL and HDL cholesterol. However, replacement with a higher carbohydrate intake, particularly refined carbohydrate, can exacerbate the atherogenic dyslipidemia associated with insulin resistance and obesity that includes increased triglycerides, small LDL particles, and reduced HDL cholesterol. In summary, although substitution of dietary polyunsaturated fat for saturated fat has been shown to lower CVD risk, there are few epidemiologic or clinical trial data to support a benefit of replacing saturated fat with carbohydrate. Furthermore, particularly given the differential effects of dietary saturated fats and carbohydrates on concentrations of larger and smaller LDL particles, respectively, dietary efforts to improve the increasing burden of CVD risk associated with atherogenic dyslipidemia should primarily emphasize the limitation of refined carbohydrate intakes and a reduction in excess adiposity.

 

[MaxBrenner]

Dietary Carbohydrate Modifies the Inverse Association Between Saturated Fat Intake and Cholesterol on Very Low-Density Lipoproteins. Dietary Carbohydrate Modifies the Inverse Ass... [Lipid Insights. 2011] - PubMed - NCBI


Wood AC, Kabagambe EK, Borecki IB, Tiwari HK, Ordovas JM, Arnett DK.
Source

Department of Epidemiology, University of Alabama at Birmingham, School of Public Health, Birmingham, AL 35294, USA.

Abstract

We aimed to investigate the relationship between dietary saturated fat on fasting triglyceride (TG) and cholesterol levels, and any mediation of this relationship by dietary carbohydrate intake. Men and women in the NHLBI Genetics of Lipid-Lowering Drugs and Diet Network (GOLDN) study (n = 1036, mean age ± SD = 49 ± 16 y) were included. Mixed linear models were run with saturated fat as a predictor variable and fasting TG, very low density lipoprotein cholesterol (VLDL-C), low density cholesterol (LDL-C) and high density cholesterol (HDL-C) as separate outcome variables. Subsequent models were run which included dietary carbohydrate as a predictor variable, and an interaction term between saturated fat and carbohydrate. All models controlled for age, sex, BMI, blood pressure and dietary covariates. In models that included only saturated fat as a predictor, saturated fat did not show significant associations with fasting lipids. When carbohydrate intake and an interaction term between carbohydrates and saturated fat intake was included, carbohydrate intake did not associate with lipids, but there was an inverse relationship between saturated fat intake and VLDL-C (P = 0.01) with a significant interaction (P = 0.01) between saturated fat and carbohydrate with regard to fasting VLDL-C concentrations. Similar results were observed for fasting TG levels. We conclude that, when controlling for carbohydrate intake, higher saturated fat was associated with lower VLDL-C and TGs. This was not the case at higher intakes of carbohydrate. This has important implications for dietary advice aimed at reducing TG and VLDL-C levels.

 

[dave]

Obviously not that tired. Nice work.

 

[MaxBrenner]

One-year effects of increasingly fat-restricted, carbohydrate-enriched diets on lipoprotein levels in free-living subjects. One-year effects of increasingly fat-r... [Proc Soc Exp Biol Med. 2000] - PubMed - NCBI


Knopp RH, Retzlaff B, Walden C, Fish B, Buck B, McCann B.
Source

Northwest Lipid Research Clinic and the Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington 98104, USA. rhknopp@u.washington.edu

Abstract

Restriction of all dietary fat is a popular strategy for restricting saturated fat intake to lower LDL cholesterol. Some authorities advise the restriction of fat intake to the extreme of less than 10% of daily energy on the assumption that more fat restriction is better. The two studies described herein address questions relating to whether increasing fat restriction produces proportionally increasing benefit on cardiovascular risk factors in hyperlipidemic subjects. The first study is the Dietary Alternatives Study (DAS). The DAS was conducted in 531 male Boeing employees over a 2-year period. Subjects were defined as hypercholesterolemic (HC) or combined hyperlipidemic (CHL) based on age-specific 75th percentiles for plasma LDL-C and triglyceride levels. Hypothesis test analyses were performed at 1 year. HC subjects were randomized to diets taught to attain fat intakes of 30, 26, 22, and 18% (Diets levels 1-4, respectively). CHL subjects (slightly fewer in number) were randomized to Diets 1-3. After 1 year, subjects' total fat intakes were 27, 26, 25, and 22% of energy (en%), resulting in saturated fat intakes of 8, 7, 7, and 6%, respectively. In HC subjects the greatest LDL-C decrease was with Diet 2 (mean of 13.4%) and in CHL subjects with Diet 1 (7.0%). Surprisingly, plasma triglyceride concentrations rose in HC subjects 20% and 40% above baseline on Diets 3 and 4, respectively, with reciprocal reductions in HDL cholesterol of 2.5% and 3%, respectively. Furthermore, apo B reductions were attenuated below Diet 2 in HC subjects and Diet 1 in CHL subjects, and no further reductions were seen in plasma glucose and insulin concentrations, blood pressure, or body weight. Measurements of plasma total fatty acid composition showed a slight increase in plasma palmitate, whereas stearate decreased slightly, supporting the idea that de novo synthesis of palmitic acid was increased in the chronic high-carbohydrate feeding condition. The second study asked if the most effective diet in HC subjects, Diet 2, has an equivalent effect in women and men. To answer this question, men and women Boeing employees were taught the closely similar National Cholesterol Education Program (NCEP) Step II diet. After 6 and 12 months, equivalent reductions in LDL cholesterol were observed in women compared with men. HDL cholesterol levels in men were unchanged from baseline at 6 and 12 months, but were reduced 8% in HC women, with accompanying decreases of 18% in HDL2-cholesterol and 5% in apoprotein A-I (all P < 0.01). These data indicate that intakes of fat below about 25 en% and carbohydrate intake above approximately 60 en% yield no further LDL-C lowering in HC and CHL male subjects and can be counterproductive to triglyceride, HDL-C, and apo B levels. This lack of benefit appears to be explained by an enhanced endogenous synthesis of palmitic acid, which negates the benefit of further saturated fat restriction. The HDL-C decrease in HC women may have a similar cause and points to an underlying male-female difference. Alternative dietary approaches to limit saturated fat intake deserve intensive study.

 

[MaxBrenner]

Obviously not that tired. Nice work.

Got a second wind

 

[dave]

Got a second wind

Too many mars bars as a late night snack.

 

[MaxBrenner]

10 squares of cadbury choc!

 

[MaxBrenner]

The complex and important cellular and metabolic functions of saturated fatty acids. The Complex and Important Cellular and Metabolic Functions of Saturated Fatty Acids


Legrand P, Rioux V.
Source

Laboratoire de Biochimie-Nutrition Humaine, Agrocampus Rennes, INRA USC 2012, 65 rue de Saint-Brieuc, CS 84215, Rennes Cedex, France. philippe.legrand@agrocampus-ouest.fr

Abstract

This review summarizes recent findings on the metabolism and biological functions of saturated fatty acids (SFA). Some of these findings show that SFA may have important and specific roles in the cells. Elucidated biochemical mechanisms like protein acylation (N-myristoylation, S-palmitoylation) and regulation of gene transcription are presented. In terms of physiology, SFA are involved for instance in lipogenesis, fat deposition, polyunsaturated fatty acids bioavailability and apoptosis. The variety of their functions demonstrates that SFA should no longer be considered as a single group.