Making Sense of the Science on Sodium June 25, 2015 Lawrence J. Appel, MD, MPH C. David Molina, M.D., M.P.H. Professor of Medicine, Epidemiology and International Health Johns Hopkins University Chair, Lifestyle and Cardiometabolic Health Council of the American Heart Association

Outline Benefits of reducing sodium intake Sodium intake recommendations Explanations for conflicting results in sodium and health studies Conclusions from review of the evidence Feasibility (taste adaptation) Synergy with other dietary recommendations

Big Picture: Worldwide, Elevated BP is the Leading Cause of Preventable Deaths Global health risks: WHO, 12/09http://

Magnitude of the BP Epidemic 54% of strokes and 47% of coronary heart disease events attributed to elevated BP 1 26% of adults worldwide (971 million) have hypertension 2 Lifetime risk 3 of developing hypertension is 90% 1 Lawes CM Lancet 2008;371: Kearney Lancet 2005;305:217 3 Vasan JAMA 2002; 287:1003

Systolic Blood Pressure Typical Diet DASH Diet 1,500 2,400 3,300 Sodium Level: mg/d per day Sacks, NEJM 2001 As Sodium Intake Is Reduced, So is Blood Pressure

Low Estimate High Estimate Total Deaths274,000505,000 Heart Deaths145,000383,000 Stroke Deaths30,00083,000 Major CVD deaths192,000516,000 Estimated Deaths Prevented over 10 Years from Gradual Sodium Reduction (4% Reduction/Year for 10 Years) Coxson, HTN 2013;61:564-70

Sodium Guidelines and Recommendations 2010 Dietary Guidelines for Americans o General population: Reduce to <2,300 mg/day o Special populations (below): Reduce to 1,500 mg/day o Persons ≥ 51 years old o African Americans o Persons with high blood pressure, diabetes, or chronic kidney disease 2015 Dietary Guidelines Advisory Committee Report o General population: Reduce to <2,300 mg/day for (or age-appropriate Dietary Reference Intake amount o Persons with prehypertension or hypertension: follow AHA/ACC (see below) Healthy People 2020 o Reduce mean U.S. population sodium intake to 2,300 mg/day by 2020 Institute of Medicine, Strategies to Reduce Sodium Intake in the US, 2010 report o Reduce the sodium content of the U.S. food supply AHA/ACC Guideline on Lifestyle Management to Reduce Cardiovascular Risk (Eckel et al, Circulation 2014, 129 (supp. 2) S79-S99) o To lower blood pressure, reduce to 2,400 mg/day o Reduce to 1,500 mg/day to lower BP even more o Lower sodium by 1,000 mg/day even if 1,500 or 2,400 mg/day goal cannot be met

What Do They All Have in Common? Average American sodium intake (for individuals ages 2 years and older) = 3,478 mg/d --- at least 1,000 mg/d greater than any of the recommendations. The debate over the ultimate target for sodium limits shouldn’t delay or derail us from taking steps to reduce our excessive intakes.

Governments and Health Agencies Worldwide are Targeting Sodium Reduction The U.S. Food and Drug Administration is preparing to issue guidelines for the food industry to voluntarily reduce sodium in packaged and restaurant foods. The U.S. Dept. of Agriculture and Dept. of Health and Human Services are addressing the sodium content of the U.S. food supply through public health campaigns, educational efforts, and monitoring sodium content of foods and population sodium intake. The World Health Organization supports governments to implement the "Global action plan to reduce non-communicable diseases" including a target to reduce global salt intake 30% by Health Canada’s goal is to reduce average Canadian sodium intake to 2,300 mg/day by 2016, through consumer awareness and education, supporting sodium reduction research, and providing guidance to assist the food industry in lowering sodium in processed foods. Sources : 1 Centers for Disease Control and Prevention, ‘Sodium Reduction Toolkit: A Global Opportunity to Reduce Population-Level Sodium Intake’; 2 Health Canada, ‘Sodium in Canada’, June 2012.

Why the fuss about sodium? Scientific issues – Methodologic ‘landmines’ – Challenges of measuring sodium – High cost of high quality sodium research in humans

Why the fuss about sodium? Commercial interests – Cheap ingredient, increases profit Role of government Types of evidence to guide policy

Measurement of Na Intake Optimal  Multiple, high quality 24 hour urine collections Suboptimal  Single or poor quality 24 hour urine collection  Spot, overnight or timed urine  24 hour dietary recall or diet history

Best Evidence: As Sodium Intake* Increases, so Does the Risk of Cardiovascular Disease (2,275 Individuals with Prehypertension) Cook, Circ 2014:129:981 *Based on 24hr urines (median = 5)

Recent Media Headlines

Taste preferences for salt are shaped by what we eat early in life. Schools are an important setting to introduce and reinforce the benefits of lowering sodium intake. Our taste buds adapt to eating less salt. No evidence that gradual reduction in sodium intake leads to loss of taste or food enjoyment Feasibility: Taste Adaptation to Lower Sodium

Sodium reduction is a component of a healthy dietary pattern that emphasizes fruits, vegetables and whole grains; includes low-fat dairy products, poultry, fish and nuts; and limits red meat, sweets and sugar-sweetened beverages. Decrease portion size  decrease sodium Increase fruit and vegetable intake while decreasing portion size of other foods  decrease sodium AND increase potassium Synergistic Efforts

Conclusion Elevated blood pressure is the leading cause of preventable death worldwide No (minimal) debate about lowering sodium intake to 2,300 mg/d Major methodological issues limit the usefulness of recent studies as a basis for guiding policy, much less reversing recommendations

Bottom Line (Unchanged) The estimated benefits of sodium reduction are substantial and warrant major public health efforts to reduce salt intake Prevailing recommendations align with best evidence and do not warrant any change in policy

AHA Science Advisory: Methodological Issues in Cohort Studies that Relate Sodium Intake to CVD Outcomes (Cobb et al., Circulation, Feb. 2014) –Reviews key methodological issues that may account for inconsistency of results in studies of sodium intake and CVD outcomes O’Donnell et al. Urinary Sodium and Potassium Excretion, Mortality, and Cardiovascular Events. New England Journal of Medicine, August 2014 –Excessive sodium consumption has dire impact on global health, new study findsExcessive sodium consumption has dire impact on global health, new study finds –Study underscores excessive sodium consumption as a global health problemStudy underscores excessive sodium consumption as a global health problem Graudal et al. Compared with usual sodium intake, low- and excessive-sodium diets are associated with increased mortality: A meta-analysis. American Journal of Hypertension, April 2014 –Reduced salt intake still criticalReduced salt intake still critical –American Heart Association stands by its sodium recommendationsAmerican Heart Association stands by its sodium recommendations For more info visit hyperlinks above or & Resources: AHA Resources on Recent Controversial Sodium Science