NUTRITION IN THE AGE OF EVIDENCE D A N A H. M A N N I N G P H A R M. D., R. D., L D N

Transcription

1 NUTRITION IN THE AGE OF EVIDENCE D A N A H. M A N N I N G P H A R M. D., R. D., L D N

2 OBJECTIVES List controversial points from the current Dietary Guidelines for Americans (DGA). Recognize the policy implications of the DGA recommendations. Critique the development of the Guidelines. Explore the best available scientific evidence as it relates to consumption amounts and disease risk for sodium, fat, cholesterol, and sugar. Contrast this information with the 2015 DGA Formulate reasonable evidence-based nutrition recommendations for patients.

3 CURRENT DIETARY GUIDELINES 2010 Dietary Guidelines for Americans Foods to reduce Reduce daily sodium to less than 2300mg or 1500mg Consume less than 35% of calories from total fat Consume less than 10% of calories from saturated fat Consume less than 300mg per day of cholesterol Reduce the intake of calories from solid fats and added sugars

4 HOW DID WE GET HERE?

5 HISTORY OF THE DIETARY GUIDELINES The Dietary Guidelines for Americans has been published jointly every 5 years since 1980 by the Department of Health and Human Services (HHS) and the Department of Agriculture (USDA) USDA has been making recommendations for far longer... How many food groups are there? Groups? It s a Pyramid! Pyramid? It s a plate!

6 HISTORY OF THE DIETARY GUIDELINES

7 NUTRIENTS OF INTEREST RDA = recommended dietary allowance, revised every 5-10 years (1940 s) These target levels are developed by the Food and Nutrition Board of the Institute of Medicine (National Academy of Sciences) RDA Dietary Reference Intakes (DRI)

8 WHAT INFLUENCE DO THE GUIDELINES HAVE? Nutrition policy, education, outreach, and assistance Health Education / curricula School meal programs WIC, SNAP Food Labeling Healthy People 2020 Initiatives in HHS, NIH, NHLBI, ODPHP, CDC, All federal dietary guidance for the public is required to be consistent with the Dietary Guidelines.

9 CRITIQUE OF ADMR/DRI PROCESS The DGA development process allows space for non-scientific influences Public/industry comment on scientific report and issuance of final guidelines by overarching agencies (USDA/HHS) The agencies have the final say, rather than the DGA Advisory Committee ***This is where industry lobbyists and Congress can make their mark ***

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11 CRITIQUE OF ADMR/DRI PROCESS The 2015 Guidelines Advisory Committee Environmental Impact House and Senate put restrictions in the 2016 Ag Appropriations Bill limiting anything said about the environment.

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13 OTHER CRITIQUE Focus on reducing incidence of coronary heart disease in 1977 DGA Reduction in dietary fat to <30% kcal (<10% from sat fat) Did the evidence support this? CHD tended to be related to serum cholesterol Cholesterol tended to be related to saturated fat intake Data was from epidemiologic studies The DGA did not make reference to any available RCT at the time

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15 Senators don t have the luxury that the research scientist does of waiting until every last shred of evidence is in

16 nion/why-is-the-federal-governmentafraid-of-fat.html

17 SEE FOR OURSELVES. When/Why do we have debate about health issues? The answer may be impossible to know The evidence is tenuous The ultimate effect is small We have a believe about a mechanism The stakes are high

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20 OUTCOMES DOE Disease Oriented Evidence Change in surrogate markers (blood levels, anthropomorphic measurements, biomarkers) Not the disease itself but correlated with the disease POEM Patient Oriented Evidence that Matters Change in Morbidity Change in rates of disease (mortality)

21 NUTRITION EXAMPLES DOE Reduce blood pressure Reduce blood sugar Reduce lipid levels Increase antioxidant levels POEM Reduce death Reduce diabetes or CKD Reduce cardiovascular disease Reduce incidence of cancer

22 WHAT IS THE RELATIONSHIP BETWEEN DIETARY PATTERNS AND RISK OF CARDIOVASCULAR DISEASE? 2015 DGAC Conclusions Higher fruits, vegetables, whole grains, low fat dairy, seafood Lower red and processed meat, refined grains, sugar sweetened foods/drinks, saturated fat, cholesterol, and sodium DGAC Grade: Strong 2010 Reduce daily sodium to less than 2300mg or 1500mg Consume less than 35% of calories from total fat (20-35%) Consume less than 10% of calories from saturated fat Consume less than 300mg per day of cholesterol Limit the consumption of foods that contain refined grains Reduce the intake of calories from solid fats and added sugars

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24 SODIUM DOES SODIUM RESTRICTION LOWER BLOOD PRESSURE? 3 meta analyses/reviews (167, 34, and 11 studies) Reduction in salt intake for >4 weeks lowers BP BP reduction of 1% normotensive, 3.5% HTN (5-10mmHg) Regardless of race or sex 4 weeks to 6 months A reduction from grams/day to 5-6 grams/day

25 SODIUM

26 SODIUM DOES REDUCING SODIUM IN THE DIET REDUCE THE RISK OF DEATH? Cochrane review studies NO EVIDENCE of reduction in all-cause mortality Weak evidence of benefit for cardiovascular mortality and events RR 0.77 ( , n=5912) Meta analysis of RCT s: mg/day No statistically significant difference in all-cause mortality and CVD events Mortality: RR=0.90 (95% CI 0.58 to 1.40) for normotensive subjects and RR=0.96 (95% CI 0.83 to 1.11) for hypertensive subjects; CVD events: RR=0.71 (95% CI 0.42 to 1.20) for normotensive subjects and RR=0.84 (95% CI 0.57 to1.23) for hypertensive subjects. Reanalysis (combined) = some reduction in CVD events RR=0.80 (95% CI 0.64 to 0.99) NNT = 48 BUT.no significant reduction in mortality.

27 SODIUM DOES REDUCING SODIUM IN THE DIET REDUCE THE RISK OF DEATH? Well designed cohort trial (NEJM 2014;371: ) measured sodium levels, 101,945 subjects, 3.7 years The lowest risk of death and cardiovascular events was seen among participants with an estimated sodium excretion between 3 and 6 grams per day

28 CHOLESTEROL

29 CHOLESTEROL QUESTION: SHOULD WE REDUCE DIETARY CHOLESTEROL TO PREVENT HEART DISEASE OR DEATH? There are no well-designed RCT s looking at using a lowcholesterol diet to reduce acquired high cholesterol Dietary interventions: plant sterols/stanols, omega 3 fatty acids, protein, and dietary fiber No conclusions can be drawn about death, ischemic heart disease, age at death 40 studies, 361,923 subjects Dietary cholesterol = No significant association with CAD, ischemic or hemorrhagic stroke

30 What food has the most saturated fat content? 1) 85% ground Beef (10.6g/100g) 2) Bacon (41.7g/100g) 3) Butter (51.4g/100g) 4) Coconut (57.2g/100g)

31 SATURATED FAT QUESTION: DOES REDUCING SATURATED FAT HELP PREVENT HEART DISEASE AND DEATH?

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33 TOTAL FAT

34 TOTAL FAT QUESTION: DOES REDUCING TOTAL DIETARY FAT HELP PREVENT DISEASE AND DEATH? A fat intake decrease ~40% of energy to <30% of energy No reduction in risk of CHD, stroke, CVD No reduction in colorectal cancer No reduction in breast cancer

35 TOTAL FAT QUESTION: DOES REDUCING TOTAL DIETARY FAT HELP PREVENT DISEASE AND DEATH?

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38 SUGAR NNH over ~15 years 80grams 100 grams 125 gram BASE s LINE

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40 DOES ANYTHING WE DO HELP? 44 trials (18,175 subjects) Dietary advice by health personnel is effective to: Increase fruit and vegetable intake by 1.18 servings/day Increase fiber intake by 6.5 grams/day Decrease total fat intake by 4.48% and saturated fat intake by 2.39% Reduce BP (2.61 mmhg systolic) Reduce lipid levels (0.15 mmol/l LDL) Possibly reduce cardiovascular events (HR 0.59, 95% CI )

41 MEDITERRANEAN DIET High monounsaturated/saturated fat ratio Low to moderate red wine consumption High legumes/whole grains/complex carbs Minimize sugars High consumption of fruits/vegetables Fish > meat Moderate dairy MANY VARIATIONS!!!!!

42 MEDITERRANEAN DIET Meta analysis: 9 studies, 514,118 participants Prospective cohort trials of primary prevention 8% relative reduction in risk of death (all-cause) (*sig) 10% reduction in risk of cardiovascular disease(*sig) 6% reduction in risk of cancer (*sig) 13% reduction in risk of neurodegenerative disease (*sig) Primary prevention of CVD (PREDIMED) - RCT 7447 at-risk men, unrestricted energy, supplemented with olive oil or nuts Significant decrease in (AMI, stroke, death from CV causes) NNT = 94 Non-significant decrease in total mortality.

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46 CONCLUSIONS Dietary guidelines = some good, some not so good?evidence breakdown? There will be a lag time between science and the DGA DGA evidence focuses on surrogate markers Greater transparency The debate about what constitutes a healthy diet is far from over Differences in outcomes are mostly found at extremes and are pretty small absolute values Is this just about being better at keeping unhealthy people alive? Unlikely to ever be able to get single nutrient causality Whatever the issue is, it should be based on the best available evidence..and a healthy dose of common sense