Going Coconut over Saturated Fat? Why So Much Confusion? Part 1 Interpreting Conflicting Research

Transcription

1 Going Coconut over Saturated Fat? Why So Much Confusion? Part 1 Interpreting Conflicting Research

2 Disclosures Alice H Lichtenstein Board Member/Advisory Panel Food and Nutrition Board, National Academies of Sciences, Engineering, and Medicine Nutrition Committee, American Heart Association Employee Tufts University Director, Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging Gershoff Professor of Nutrition Science and Policy, Friedman School Research Support NIH, USDA

3 Learning Outcomes Synthesize clinical and observational data to summarize the link between dietary fat type and cardiovascular disease (CVD) risk, with specific emphasis on saturated fat. o Observational (epidemiological) studies o Intervention studies o Systematic review/meta-analysis o Summarize the totality of the data

4 Audience Question Is the message to limit saturated fat intake out of date? a. Yes b. No c. Maybe d. I am totally confused

5 Observational Studies Keys Seven Countries Study Keys A. Et al. Acta Med Scand Suppl. 1966;460:1

6 Keys Seven Countries Study Kromhout D, et al. Prev Med 1995:24;308

7 Relative Risk of CHD Mortality and P:S Ratio Zatonski WA, Willett W. BMJ 2005; 331:187-8

8 Saturated Fat and Coronary Heart Disease Mortality Perth, Western Australia, Women (75.2±6 2.7 y) 1 th quartile Quartiles SFA intake 4 Western Norway B-Vitamin Intervention th quartile Trial Blekkenhorst LC et al. AJCN. 2015;101:1263

9 Saturated Fats Compared With Unsaturated Fats and Carbohydrates and Coronary Heart Disease (NHS) Li Y et al. JACC. 2015;66:

10 Intervention Studies MRC Soya-Bean Oil Trial 2 Prevention Replacement SFA with soybean oil Lean meat, fish, non-fat milk and clear soup Forbidden (butter, margarine, cookingfat, other oils, fat meat, whole milk, cheese, egg yolk, most biscuits and cakes) 5 years Medical Research Committee (UK) Lancet 1968:Sept 18 th

11 MRC Soya-Bean Oil Trial 2 Prevention % surviving free of relapse and surviving Years in Trial 5 years Medical Research Committee (UK) Lancet 1968:Sept 18 th

12 LA Veterans Diet Study 1 and 2 Prevention Domiciliary unit of the Los Angeles Veterans Center 40% total fat, unsaturated fat tripled at the expense of SFA Dayton S. Lancet November 1968:1060

13 LA Veterans Diet Study 1 and 2 Prevention Sudden Death or Myocardial Infarction Dayton S. Lancet November 1968:1060

14 Oslo Diet-Heart Study 2 Prevention Low SFA, high PUFA diet - PUFA oil for cooking, baking and sauces - Fish, whale meat and low-fat meat - Fiber-rich bread - Sandwich fillings; fish or vegetable preferable, low-fat cheese or meat acceptable 11 year follow-up Leren P. Circ. 1970; 42:935-42

15 Oslo Diet-Heart Study 2 Prevention Fatal Myocardial Infraction % survival 11 year follow-up Leren P. Circ. 1970; 42:935-42

16 Finnish Mental Health Study 1 Prevention 2 hospitals, cross-over design (6 yr/phase) Ordinary milk replaced by emulsion of soybean oil and skim milk (filled milk) Butter and ordinary margarine replaced with soft margarine with high PUFA content (P/S ratio ) Miettinen M et al. Lancet 1972:Oct. 21 Turpeninen O, et al. Int J Epi 1979;8:99

17 Finnish Mental Health Study 1 Prevention 15 Experimental Diet Control Diet (Years on Trial) Miettinen M et al. Lancet 1972:Oct. 21 Turpeninen O, et al. Int J Epi 1979;8:99 6 years 12 years

18 Leiden Intervention Trial 2 Prevention 2-year intervention (no control group) P/S ratio >2 Continuous instruction of patients and spouses 2 year follow-up Arntzenius AC et al. NEJM 1985:312;805

19 Leiden Intervention Trial 2 Prevention 2 year follow-up Arntzenius AC et al. NEJM 1985:312;805

20 St. Thomas Atherosclerosis Regression Study (STARS) - 2 Decrease SFA to 8%E-10%E Increase n-6 and n-3 FA to 8% Increase plant derived fiber (pectin) to 3.8g/1000 kcal Watts GF et al. Am J Card 1994:73;328 3y intervention

21 St. Thomas Atherosclerosis Regression Study (STARS) diet intervention Change in minimum width segment (mm) control Watts GF et al. Am J Card 1994:73;328

22 Systematic Review/Meta-Analyses Current Era Why have questions emerged about dietary recommendations with regard to saturated fat?

23 Systematic Review of Evidence Supporting Causal Link Between Dietary Factors and Coronary Heart Disease Mente A. et al. Arch Intern Med 2009;169:

24 Systematic Review of Evidence Supporting Causal Link Between Dietary Factors and Coronary Heart Disease Mente A. et al. Arch Intern Med 2009;169:

25 Meta-analysis of Prospective Cohort Studies Evaluating Association of Saturated Fat With CVD Death Meta-analysis of Prospective Cohort Studies Evaluating Association of Saturated Fat With CVD Death Siri-Tarino, PW, et al. Am J Clin Nutr 2010;91:

26 Saturated Fat, Carbohydrate and Cardiovascular Disease 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. Siri-Tarino, PW, et al. Am J Clin Nutr 2010;91:

27 Major Types of Dietary Fat and Risk of Coronary Heart Disease: A Pooled Analysis of 11 Cohort Studies Jakobsen, M. U et al. Am J Clin Nutr 2009;89:

28 Major Types of Dietary Fat and Risk of Coronary Heart Disease: A Pooled Analysis of 11 Cohort Studies Jakobsen, M. U et al. Am J Clin Nutr 2009;89:

29 Meta-analysis of Randomized Controlled Trials Replacing SFA with PUFA Relative Risk of MI or CHD Death Mozaffarian D et al. PLoS Med ;7:e

30 Meta-analysis of Randomized Controlled Trials Replacing With PUFA, Carbohydrate, MUFA Relative Risk of CHD for Each 5% Energy Intake Mozaffarian D, et al. PLoS Med ;7:e

31 Ann Intern Med. 2014;160: Conclusion: Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.

32 Saturated Fat and CVD Prevention Small but potentially important reduction in cardiovascular risk due to a reduction of saturated fat intake. Replacing saturated fat with; o polyunsaturated fat appears to be a useful strategy o carbohydrate appears less useful o monounsaturated fat was unclear due to inclusion of only one trial. Hooper L, Martin N, Abdelhamid A, Davey Smith G. Cochrane Database of Systematic Reviews 2015, Issue 6.

33 Effects of Saturated Fatty Acids on Serum Lipids and Lipoproteins: A Systematic Review and Regression Analysis Results of the multiple regression analysis indicated; The most favorable effects on the serum lipoprotein profile were observed when dietary SFA was replaced with cis-pufa or cis- MUFA. For total and LDL cholesterol the most favorable effects were observed for cis-pufa. Mensink RP, WHO, 2016

34 Effects of Saturated Fatty Acids on Serum Lipids and Lipoproteins: A Systematic Review and Regression Analysis Multiple regression analysis indicated; No significant gender-specific differences No systematic affected of study publication date, or inclusion of studies using liquid diets. Conclusions did not change if subjects were stratified for baseline lipid levels. Mensink RP, WHO, 2016

35 Message Translation Early work linked replacement of saturated fat with PUFA and reduced CVD risk. At some point the message shifted to decrease saturated fat by limiting total fat.

36 Audience Question When evaluating emerging data for saturated fat and CVD risk, which of the following should be taken into consideration? a. Absolute amount of saturated fat b. Relative amounts of saturated fat and unsaturated fat c. Relative amounts of saturated fat and carbohydrate. d. Both b and c.

37 Interpreting the Totality of the Data Early work linked replacement of saturated fat with PUFA and reduced CVD risk. At some point the focus shifted to decrease saturated fat. Resulted in an increase in refined carbohydrate. When evaluating the literature need to take into consideration differences/changes in saturated fat and replacement macronutrient.

38 Practice Applications Majority of the evidence supports the recommendation to substitute sources of saturated fat with unsaturated fat, particularly PUFA. Address questions about why there are conflicting messages by explaining that the replacement source of calories is as important as changes in the absolute amount of saturated fat. As new data emerges evaluate on the basis of changes in dietary patterns rather than individual dietary components.