Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk

Transcription

1 NUTRI-BITES Webinar Series Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk will begin at the top of the hour Audio for today s presentation is being broadcast over your computer speakers, so be sure they are turned on and the volume is up Today s presentation in handout form can be downloaded from: (type in your browser) NUTRI-BITES Webinar Series Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk July 8, 2015 Presenter: Ronald M. Krauss, MD Senior Scientist and Director, Atherosclerosis Research, Children s Hospital Oakland Research Institute Adjunct Professor, Department of Medicine, UCSF Adjunct Professor, Department of Nutritional Sciences, UC Berkley Moderator: James M. Rippe, MD Leading cardiologist, Founder and Director, Rippe Lifestyle Institute Approved for 1 CPE (Level 2) by the Commission on Dietetic Registration, credentialing agency for the Academy of Nutrition and Dietetics. 1

2 ConAgra Foods Science Institute With a mission of: Promoting dietary and related choices affecting wellness by linking evidence-based understanding with practice Webinar logistics CEUs a link to obtain your Continuing Education Credit certificate will be ed and available on this webinar s page at within 2 days. A recording of today s webinar, slides, and summary PowerPoint will be available to download as a PDF within 2 days at: The presenter will answer questions at the end of this webinar. Please submit questions by using the Chat dialogue box on your computer screen. 2

3 Today s Faculty Ronald M. Krauss, MD Senior Scientist and Director, Atherosclerosis Research, Children s Hospital Oakland Research Institute Adjunct Professor, Department of Medicine, UCSF Adjunct Professor, Department of Nutritional Sciences, UC Berkley Moderator: James M. Rippe, MD Leading cardiologist, Founder and Director, Rippe Lifestyle Institute Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk NUTRI-BITES Webinar Series Learning Objectives Summarize the effects of dietary cholesterol on lipid levels and cardiovascular disease risk Explain the basis for current dietary recommendations for saturated fat intake Describe the effects of substituting carbohydrate for fat on lipid markers of cardiovascular disease risk 3

4 Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk Ronald M. Krauss Children s Hospital Oakland Research Institute UCSF and UC Berkeley Disclosures R.M.Krauss Grant support: NIH, Dairy Research Institute, Almond Board of California Licensed patents: Methods for lipoprotein particle analysis Other: Member NHLBI Cholesterol Guidelines Panel

5 Dietary Cholesterol 5

6 Dietary cholesterol has modest and variable effects on blood cholesterol One egg: 0.1 to 6.5 mg/dl Defined diets Self-selected diets Panel on Macronutrients, IOM, 2005 Meta-analysis - no increased risk of CVD with egg consumption (except in diabetes) Shin et al., Am J Clin Nutr;98:146 59,

7 The very latest - Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis In 40 studies dietary cholesterol was not statistically significantly associated with coronary artery disease or ischemic or hemorrhagic stroke. But: studies were heterogeneous and lacked the methodologic rigor to draw any conclusions regarding effects of dietary cholesterol on CVD risk. Carefully adjusted and well-conducted cohort studies would be useful to identify the relative effects of dietary cholesterol on CVD risk. Berger et al., Am J Clin Nutr 2015 Jun 24.. [Epub ahead of print] The bottom line per 2015 US Dietary Guidelines Advisory Committee Previously, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report that dietary cholesterol is not a nutrient of concern for overconsumption. Scientific Report of the 2015 Dietary Guidelines Advisory Committee 7

8 Dietary Saturated Fats What are saturated fats? Saturated fats consist of fatty acids where the carbon chains are full ( saturated ) with hydrogen. There are dozens of types with differing chain length; most common are lauric, myristic, palmitic, & stearic. Saturated fats are mainly consumed in animal foods such as dairy products and red meat, and oils such as coconut, palm, and palm kernel oil. 8

9 Why limit saturated fat? Main rationale is to reduce risk of heart disease: When substituted for other types of fat, saturated fats raise levels of LDL ( bad ) cholesterol. Levels of LDL cholesterol are strongly linked to heart disease risk. Reducing LDL cholesterol can reduce heart disease risk. How much saturated fat do we eat? Intake has leveled off at ~11% of calories for past 15 years. Long-standing recommendations have been to limit intake to <10% of calories. 9

10 Most recent AHA Dietary Guidelines for the general population In view of the positive linear relationship among dietary saturated fat, LDL cholesterol, and CVD risk, and current US intakes, the AHA now recommends a population-wide goal [for saturated fat] of <7% of energy. Lichtenstein et al.,circulation. 114: 82-96, 2006 Evidence for benefit of dietary pattern with reduced saturated fat -DELTA Eckel RH, et al Circulation,

11 Current AHA/ACC Lifestyle Management Guidelines Advise adults who would benefit from LDL C lowering * to: Aim for a dietary pattern that achieves 5% to 6% of calories from saturated fat Reduce percent of calories from saturated fat. * Those with elevated LDL-C or CVD risk factors Eckel RH, et al Circulation, Nov But the 2015 US DGAC has not changed the saturated fat guideline for the general population The DGAC encourages the consumption of healthy dietary patterns that are low in saturated fat. The goal for the general population [is] less than 10 percent of total calories from saturated fat per day Scientific Report of the 2015 Dietary Guidelines Advisory Committee What is the evidence to support this or any target for saturated fat intake? 11

12 Digging deeper into the rationale for saturated fat restriction The major rationale has been LDL cholesterol reduction What is our current understanding of this effect? LDL is comprised of subclasses of particles with differing cholesterol content and CVD risk Large more cholesterol/particle Medium Small and very small less cholesterol/particle Increased CVD risk Reduced plasma clearance Greater entry into artery Greater retention Faster oxidation Distribution of subclasses varies widely among individuals and is independent of total LDL cholesterol Berneis and Krauss, JLR 43:1155,

13 LDL cholesterol level can misrepresent the number of LDL particles 100 mg/dl LDL-Cholesterol 100 mg/dl Larger LDL particles More cholesterol/particle Fewer LDL particles Smaller LDL particles Less cholesterol/particle More LDL particles What is effect of diet on LDL particles? Reduced carbohydrate (26 vs. 54%), but not reduced sat fat (8% vs. 15%) lowers small LDL particles Changes in LDL particles with reduced carbohydrate intake Change mg/dl Low sat fat mainly reduces large LDL Reduced carb lowers small LDL irrespective of saturated fat intake Large Medium Small V. small LDL Krauss et al. AJCN 83:1025,

14 Does increase in LDL cholesterol with higher SFAs translate to higher CVD risk? Main effect of SFAs is on larger LDL particles, which are less strongly associated with CVD risk than smaller LDL Thus, SFA-induced increases in LDL cholesterol may not signify a proportional increase in CVD risk. Carbohydrates (especially sugars) have a major influence on smaller LDL particles Since smaller LDLs have less cholesterol/particle, their levels can increase with higher carb intake without a proportional increase in LDL cholesterol. What are the health consequences of reducing dietary saturated fat below current intake levels? Show me the data! 14

15 Meta-analysis of 21 prospective cohort trials shows no significant association of saturated fat intake with heart disease or stroke What is the evidence that CVD is reduced with lower SFA intake? Coronary heart disease relative risk = 1.07 Stroke relative risk =0.81 Overall risk = 1.00 Siri-Tarino et al., Am J Clin Nutr. 91: , 2010 Meta-analysis of association of fatty acid intake with CAD in cohort studies Chowdhury et al., Ann Intern Med;160: ,

16 What is the evidence that reducing SFAs will reduce risk of heart disease? To study such an effect without complicating the results by weight loss, something must be substituted for SFAs. The best evidence from clinical trials is that substituting polyunsaturated for saturated fat reduces heart disease risk, although a recent meta-analysis has challenged this. However, from epidemiologic studies, when SFAs are replaced by carbohydrates (both sugars and simple starches) there is no reduction in heart disease risk, and there is some evidence that the risk may be greater. 16

17 Effects on heart disease risk of replacing SFAs by other fats and carbohydrates Dietary replacement (each 5% of calories) Polyunsaturated fat Predicted from lipid change Randomized clinical trials Observational cohort studies Carbohydrate Predicted from lipid change Randomized clinical trials Observational cohort studies Monounsaturated fat (e.g., olive, canola) Predicted from lipid change Randomized clinical trials Observational cohort studies Relative Risk Mozaffarian et al., PLoS Med Mar 23;7:e , 2010 Substitution of high glycemic starch for SFAs increases risk for heart attack 1.4 Relative risk of heart attack per 5% energy substitution Lowest Medium Highest Tertiles of glycemic starch intake Jakobsen et al.,am J Clin Nutr. 91:1764-8,

18 The role of reducing intakes of SFAs in prevention of heart disease: where does the evidence stand? No clear benefit of substituting carbohydrates for SFAs has been shown, although there might be a benefit if the carbohydrate is unrefined and has a low glycemic index. No clear association between SFA intake relative to refined carbohydrates and the risk of insulin resistance and diabetes has been shown. Astrup A., et al. Am J Clin Nutr 2011;93: Interactive question: What foods have been significantly associated with increased CVD outcomes? a. Cheese b. Eggs c. Butter d. Full fat yogurt e. Red meat f. Tropical oils g. None of the above h. All of the above 18

19 Although sat fat intake is not significantly associated with CVD risk, higher red meat intake is associated with increased CVD & total mortality Hazard ratio Hazard ratio Men (n=51,529) Women (n=121,700) Total red meat intake, servings per day Pan et al., Arch Intern Med. 172: , 2012 Food sources of saturated fatty acid matter: SFAs from meat are associated with higher CHD risk while SFAs from dairy are associated with lower risk Meat SFAs Other SFAs Dairy SFAs de Oliveira et al., AJCN 96:397,

20 Increase in LDL particles with high SFAs is much higher when beef is the major protein source % increase high vs. low SFAs Same increase in saturated fat (8% 15%) Mixed proteins High beef Krauss et al., AJCN 2006 Mangravite et al., J, Nutr Recipe for disaster? + +? 20

21 We should focus on eating healthy foods and food combinations/meal patterns and worry less about counting grams of saturated fat The effect of particular foods on coronary heart disease cannot be predicted solely by their content of total SFAs because: individual SFAs may have different cardiovascular effects and major SFA food sources contain other constituents that could influence CHD risk. Astrup A., et al. Am J Clin Nutr 2011;93: More on foods vs. saturated fat LDL cholesterol levels are lower after eating cheese than after eating butter with the same amount of saturated fat. Recent epidemiologic studies suggest that fermented dairy products are associated with reduced risk of heart disease independent of saturated fat. It may be that intake of red meat is responsible for much of the risk of heart disease (and diabetes) attributed to saturated fat. 21

22 What about butter? - the latest word ~1 tbsp butter/day resulted in a 6% increase in LDL-chol compared with a diet including olive oil and with a habitual diet. However, butter intake also increased HDL-chol by 4% compared with the habitual diet. Associations of butter with CVD are inconsistent. A healthy diet may leave room for moderate intake of butter for the normocholesterolemic population. However, population groups at risk of CVD and hypercholesterolemic people should keep their consumption of butter to a minimum. Engel and Tholstrop, Am J Clin Nutr 2015 July 1 [Epub ahead of print] Summary: Points to consider about saturated fat and CVD It is not clear to what extent dietary saturated fat has effects that are directly harmful to arteries as opposed to having a neutral/permissive role; whereas other dietary factors have more direct effects: Good: Fatty fish, nuts, other polyphenol-rich foods, legumes Bad Trans fats Sugars, glycemic starches The foods with which SFAs are eaten make a difference! 22

23 A few points for putting all this into practice (per RMK) Discourage dietary cholesterol and saturated fat phobia: a little butter won t kill you. Fermented dairy products (e.g. Greek yogurt) can be encouraged but watch out for sugar content! Lean meat can have a role in a healthy diet, but avoid combining it with high animal fat and processed carbs, and limit intake of processed meats. Some references Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fat, carbohydrate, and cardiovascular disease. Am J Clin Nutr. 2010: 91: Astrup A., et al.the role of reducing intakes of saturated fat in the prevention of cardiovascular disease: where does the evidence stand in 2010? Am J Clin Nutr : Chowdhury R, et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med. 2014;160): Erratum in: Ann Intern Med. 2014; 160:658 Astrup A. Yogurt and dairy product consumption to prevent cardiometabolic diseases: epidemiologic and experimental studies. Am J Clin Nutr (5 Suppl):1235S-42S. Berger S, et al, Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis Am J Clin Nutr Jun 24. [Epub ahead of print] 23

24 Thank you! Questions? 24

25 Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk NUTRI-BITES Webinar Series Based on this webinar the participant should be able to: Summarize the effects of dietary cholesterol on lipid levels and cardiovascular disease risk Explain the basis for current dietary recommendations for saturated fat intake Describe the effects of substituting carbohydrate for fat on lipid markers of cardiovascular disease risk ConAgra Foods Science Institute Nutri-Bites Webinar details A link to obtain your Continuing Education Credit certificate will be ed within 2 days Today s webinar, including certificate link, will be available to download within 2 days at: For CPE information: acontinelli@rippelifestyle.com Recent CEU webinars archived at the ConAgra Foods Science Institute website: Nutrition Support for the Bariatric Patient Critical Evaluation of Nutrition Research Functional Foods: Phytochemicals Hidden Nutrition Gems Sodium: Too much, too little or just right? A Decade of Nutrigenomics: What Does it Mean for Dietetic Practice? Ethics for All: Applying Ethics Principles across the Dietetics Profession 25

26 Next ConAgra Foods Science Institute Nutri-Bites Webinar Towards a Sustainable Food Supply: Myths and Realities Jack Bobo, JD, MS Senior Advisor United States Department of State Washington, DC Date: September 17, pm EDT/1-2 pm CDT How are we doing? Stay on the line for a brief survey about today s ConAgra Foods Science Institute Nutri-Bites webinar: Setting the Record Straight on Cholesterol, Saturated Fat, and Heart Disease Risk Thank you! 26