Sodium: Too much, too little or just right?

Transcription

1 NUTRI-BITES Webinar Series Sodium: Too much, too little or just right? November 6, 2014 Presenter: Robert P. Heaney, MD John A. Creighton University Professor/Professor of Medicine Creighton University 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.

2 ConAgra Foods Science Institute With a mission of: Promoting dietary and related choices affecting wellness by linking evidence-based understanding with practice

3 Webinar logistics CEUs a link to obtain your personalized Continuing Education Credit certificate will be ed 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.

4 Today s Faculty Robert P. Heaney, MD John A. Creighton University Professor/Professor of Medicine Creighton University Moderator: James M. Rippe, MD Leading cardiologist, Founder and Director, Rippe Lifestyle Institute

5 NUTRI-BITES Webinar Series Sodium: Too much, too little or just right? Learning Objectives After the webinar the participant will be able to: Review the evolution of sodium intake recommendations Understand the physiology related to regulating sodium metabolism Discuss latest findings of the association of sodium intake to health outcomes Outline practical dietary strategies dietitians can offer clients as the science on sodium evolves

6 SODIUM: TOO MUCH, TOO LITTLE, OR JUST RIGHT? Robert P. Heaney, MD, FACP, FASN Creighton University Osteoporosis Research Center

7 Disclosures for: Robert P Heaney, M.D. AFFILIATION/FINANCIAL INTERESTS Grants/Research Support: CORPORATE ORGANIZATION none Scientific Advisory Board/Consultant: Speakers Bureau: Int l Dairy Foods Assn. none Stock Shareholder: none Other Financial or Material Support/Honorarium: none

8 TIME: March 15,

9 SOME SODIUM INTAKE FACTS 2004 IOM recommendations for adults: < 1,500 mg/day up to age 50 < 1,300 mg/day from 50 to 70 < 1,200 mg/day after age 70

10 SOME SODIUM INTAKE FACTS 2004 IOM recommendations for adults: < 1,500 mg/day up to age 50 < 1,300 mg/day from 50 to 70 < 1,200 mg/day after age 70 mean Na intake in U.S. & Europe: 3,450 mg/day (95% probability range: 2,600 5,000 mg/day)

11 SOME SODIUM INTAKE FACTS 2004 IOM recommendations for adults: < 1,500 mg/day up to age 50 < 1,300 mg/day from 50 to 70 < 1,200 mg/day after age 70 mean Na intake in U.S. & Europe: 3,450 mg/day (95% probability range: 2,600 5,000 mg/day) this intake has been stable for at least 50 years in forty five 1 st world nations

12 SODIUM INTAKE OVER TIME* populationbased studies in the UK N = 6, Urine Na (mmol/d) mean: (3450 mg) + 2 SEM 2 SEM Year Assessed McCarron et al., CJASN

13 How, in theory, are Dietary Reference Intakes (DRIs) determined? 14

14 THE DRI PROCESS (IN THEORY) first, the consequences of inadequate and excessive intakes are defined 15

15 NUTRIENT RESPONSE RVE* Risk of Deficiency EAR RDA UL Risk of Toxicity Intake of Nutrient *DRI book; IOM (2006)

16 BACKGROUND GUIDANCE this U-shaped (or J-shaped) distribution of risk is explicitly cited in the IOM s guidance documents (p. 12) 17

17 BACKGROUND GUIDANCE this U-shaped (or J-shaped) distribution of risk is explicitly cited in the IOM s guidance documents (p. 12) and is taken as the basic model for all nutrients in standard textbooks of nutritional epidemiology 18

18 THE DRI PROCESS (IN THEORY) first, the consequences of inadequate and excessive intakes are defined the focus is on harm, not on benefit 19

19 THE DRI PROCESS (IN THEORY) first, the consequences of inadequate and excessive intakes are defined avoiding the focus is on harm, not on benefit ^ 20

20 THE DRI PROCESS (IN THEORY) first, the consequences of inadequate and excessive intakes are defined avoiding a reversion back to the prevailing medical the focus is on harm, not on benefit paradigm of the ^ 1 st quarter of the 20 th century: all diseases are caused by foreign agencies microbial or toxic 21

21 RISK AT BOTH EXTREMES Risk of Harm deficiency toxicity Intake 22

22 THE DRI PROCESS first, the consequences of inadequate and excessive intakes are defined data describing intakes needed to avoid those consequences are gathered 23

23 THE DRI PROCESS first, the consequences of inadequate and excessive intakes are defined data describing intakes needed to avoid those consequences are gathered an intake just sufficient to avoid inadequacy is defined as the requirement 24

24 NUTRIENT RESPONSE RVE* Risk of Deficiency Risk of Toxicity Intake of Nutrient *DRI book; IOM (2006)

25 THE SIGMOID RESPONSE RESPONSE BENEFIT INTAKE

26 THE SIGMOID RESPONSE RESPONSE BENEFIT minimum daily requirement INTAKE

27 A VITAMIN D THRESHOLD 0.5 CALCIUM ABSORPTION FRACTION SERUM 25(OH)D (nmol/l) 28

28 THE DRI PROCESS first, the consequences of inadequate and excessive intakes are defined data describing intakes needed to avoid those consequences is gathered an intake just sufficient to avoid inadequacy is defined as the requirement recognizing that individuals will have differing requirements, an average requirement is estimated (the EAR) 29

29 THE SODIUM DRIs the IOM noted that Na effects arose not from Na, per se, but from NaCl, the form in which ~90% of ingested Na enters the body 30

30 THE SODIUM DRIs the IOM noted that Na effects arose not from Na, per se, but from NaCl, the form in which ~90% of ingested Na enters the body the IOM stated that there was not enough evidence regarding NaCl effects to establish the usual DRIs, and so proposed, instead, an AI 31

31 THE DRI PROCESS an Adequate Intake (AI) is an intake estimated when there are not sufficient data to calculate the EAR or RDA 32

32 THE DRI PROCESS an Adequate Intake (AI) is an intake estimated when there are not sufficient data to calculate the EAR or RDA how is it estimated? 33

33 THE DRI PROCESS an Adequate Intake (AI) is an intake estimated when there are not sufficient data to calculate the EAR or RDA how is it estimated? the DRI book says that is to be the average intake observed in a healthy population 34

34 THE DRI PROCESS an Adequate Intake (AI) is an intake estimated when there are not sufficient data to calculate the EAR or RDA how is it estimated? the DRI book says that is to be the average intake observed in a healthy population 35

35 THE DRI PROCESS an Adequate Intake (AI) is an intake estimated when there are not sufficient data to calculate the EAR or RDA how is it estimated? the DRI book says that is to be the average intake in a healthy population 36

36 THE SODIUM DRIs the adverse effect with increasing salt intake, which the AI seeks to minimize, is elevated blood pressure 37

37 THE SODIUM DRIs the adverse effect with increasing salt intake, which the AI seeks to minimize, is elevated blood pressure the IOM, in effect, ignored adverse effects at low intakes, i.e., the panel used a linear model rather than a U-shaped model 38

38 THE SODIUM DRIs the adverse effect with increasing salt intake, which the AI seeks to minimize, is elevated blood pressure the IOM, in effect, ignored adverse effects at low intakes, i.e., the panel used a linear model rather than a U-shaped model this explains why the BP data and the health outcomes data disagree 39

39 RISK AT BOTH EXTREMES BP is the proxy Risk of Harm toxicity Intake 40

40 RISK AT BOTH EXTREMES BP is the proxy Risk of Harm presumption: any decrease in intake decreases risk or severity of cardiovascular disease at all salt intakes Intake 41

41 RISK AT BOTH EXTREMES real risk reduction up here BP is the proxy Risk of Harm Intake 42

42 RISK AT BOTH EXTREMES BP is the proxy Risk of Harm is applied down here real risk reduction up here Intake 43

43 You can say without any shadow of doubt that the authorities pushing the eat-less-salt message had made a commitment to salt education that goes way beyond the scientific facts. Drummond Rennie, M.D. Editor, JAMA 44

44 STARTING INTAKE MATTERS Health outcomes are the proxy Risk of Harm Intake 45

45 STARTING INTAKE MATTERS Health outcomes are the proxy Risk of Harm Intake 46

46 STARTING INTAKE MATTERS Health outcomes are the proxy Risk of Harm Intake 47

47 CVD EVENTS* CVD/1000 person years CVD MI N = st 2nd 3rd 4th UNa + Quartiles *Worksite Hypertension Study; Alderman, M Hypertension 25:

48 CVD EVENTS* CVD/1000 person years CVD MI N = < 2000 mg 1st 2nd 3rd 4th UNa + Quartiles > 4000 mg *Worksite Hypertension Study; Alderman, M Hypertension 25:

49 CV MORTALITY & MORBIDITY* CVD Mortality All CVD Events *Stolarz-Skrzypek et al., JAMA 2011 [pooled data from two large European studies] 50

50 TYPE I DIABETES & MORTALITY* Current (AI) Recommendation Normal Range mg/d *Thomas et al., Diabetes Care

51 RISK vs. INTAKE composite of CV death, stroke, MI, & CHF 14 cohort studies N = 154,282 O Donnell et al., Eur Heart Journal 2012 Hazard Ratio (95% CI) Urine Na (g/d) 52

52 RISK vs. INTAKE combined CV death, stroke, MI, & CHF O Donnell et al., Eur. Heart Journal 2012 Hazard Ratio (95% CI) lowest risk Urine Na (g/d) 53

53 CHF RISK vs. Na INTAKE EPIC-Norfolk Study n = 19,857 mean follow-up: 12.9 yrs Pfister et al. (2014) Eur J Heart Failure ln[adj. Hazard Ratio] lowest risk Urine Sodium (mmol/d) 54

54 CVD RISK vs. Na INTAKE 17 country study N = 101,945 mean followup: 3.7 years O Donnell et al. NEJM 371:612 (2014) Odds Ratio Sodium Excretion (g/day) 55

55 FURTHER PROBLEMS besides using a linear model instead of a U-shaped one, the IOM failed to factor in the crucial roles of Ca and K intakes, as revealed in the classic DASH studies 56

56 DASH I* three-way trial of dietary intervention standard American diet diet high in fruits and vegetables diet high in fruits & vegetables plus lowfat milk (~730 mg extra Ca) *Appel et al., NEJM 1997; 336:

57 DASH I* three-way trial of dietary intervention standard American diet diet high in fruits and vegetables diet high in fruits & vegetables plus lowfat milk (~730 mg extra Ca) Na intake held constant at ~3000 mg across all three diets *Appel et al., NEJM 1997; 336:

58 DASH I: Hypertensive Cohort* 0 Control F&V F&V + Dairy Diastolic BP (mm/hg) *Appel et al., NEJM 1997; 336:

59 DASH-I: Conclusions BP reduction was as large as produced by standard anti-hypertensive monotherapy regimens 60

60 DASH-I: Conclusions BP reduction was as large as produced by standard anti-hypertensive monotherapy regimens if applied at a population level, the full DASH diet would reduce incidence of stroke by 27 % MIs by 15 % 61

61 DASH-I: Conclusions BP reduction was as large as produced by standard anti-hypertensive monotherapy regimens if applied at a population level, the full DASH diet would reduce incidence of stroke by 27 % MIs by 15 % 62

62 DASH II Control DASH standard diet, but with three levels of Na intake high fruit, vegetable, and dairy diet, also with three levels of Na intake 63

63 Na, BP, & THE DASH DIET* Mean Systolic BP (mm Hg) Control DASH Sodium Intake Level (mg/d) *Vollmer et al. AIM 2001:135:

64 DASH OFFICIAL CONCLUSIONS emphasis remained on reducing fat and sodium role of increasing Ca & K intakes minimized or ignored entirely 65

65 DASH ANOTHER CONCLUSION the possibly harmful effects of high Na intake are magnified when the diet is inadequate in Ca and K high Ca & K intakes mitigate the possible harm of high Na intakes 66

66 NUTRITION IS LIKE AN HESTRA calcium magnesium vitamin D potassium sodium

67 Sodium is a poster child for the larger nutrient problem 68

68 THE NUTRIENT PROBLEM the field lacks a consensus on how to define normal or adequate 69

69 THE NUTRIENT PROBLEM the field lacks a consensus on how to define normal or adequate that leaves the field virtually without a target to aim at 70

70 THE NUTRIENT PROBLEM the field lacks a consensus on how to define normal or adequate that leaves the field virtually without a target to aim at and forces reliance upon empirical evidence that, e.g., intake A is better by some measurable endpoint than intake B 71

71 THE NUTRIENT PROBLEM the field lacks a consensus on how to define normal or adequate that leaves the field virtually without a target to aim at and forces reliance upon empirical evidence that, e.g., intake A is better by some measurable endpoint than intake B the evidence must be in the form of RCTs 72

72 OTHER BENCHMARKS there are several alternative benchmarks that have been proposed the one that seems best for Na is the intake that minimizes the need for the physiological compensation that occurs when Na intake is low 73

73 A BETTER BENCHMARK such compensation, for Na, is the activation of the RAAS mechanism, which becomes operative at Na intakes at or below ~3000 mg/d for an adult 74

74 RAAS A RESE MECHANISM angiotensinogen 75

75 RAAS A RESE MECHANISM angiotensinogen angiotensin I renal blood flow renin 76

76 RAAS A RESE MECHANISM ACE angiotensinogen angiotensin I angiotensin II renal blood flow renin 77

77 RAAS A RESE MECHANISM sympathetic activity ACE NaCl reabsorption & water retention angiotensinogen angiotensin I angiotensin II aldosterone secretion renal blood flow renin arteriolar constriction & rise in BP ADH secretion from pituitary 78

78 RAAS A RESE MECHANISM sympathetic activity ACE NaCl reabsorption & water retention angiotensinogen angiotensin I angiotensin II aldosterone secretion renal blood flow renin arteriolar constriction & rise in BP ADH secretion from pituitary 79

79 RAAS A RESE MECHANISM sympathetic activity ACE NaCl reabsorption & water retention angiotensinogen angiotensin I angiotensin II aldosterone secretion renal blood flow renin arteriolar constriction & rise in BP ADH secretion from pituitary 80

80 RAAS A RESE MECHANISM sympathetic activity ACE NaCl reabsorption & water retention angiotensinogen angiotensin I angiotensin II aldosterone secretion renal blood flow renin arteriolar constriction & rise in BP ADH secretion from pituitary 81

81 Na INTAKE & RAAS RESPONSES* Plasma Renin Activity (ng/ml/hr) Urine Sodium (mmol/d) Aldosterone ( g/d) Urine Sodium (mmol/d) *Brunner et al., NEJM (1972) 286:

82 Na INTAKE & RAAS RESPONSES* Plasma Renin Activity (ng/ml/hr) Urine Sodium (mmol/d) Aldosterone ( g/d) Urine Sodium (mmol/d) *Brunner et al., NEJM (1972) 286:

83 Na INTAKE & RAAS RESPONSES* Plasma Renin Activity (ng/ml/hr) Urine Sodium (mmol/d) Aldosterone ( g/d) Urine Sodium (mmol/d) *Brunner et al., NEJM (1972) 286:

84 MI RISK & RENIN LEVELS* *Alderman, M. NEJM 1991; Am J Hypertension 1997 MIs per 1000 Person-Years High Moderate Risk Level Low Low High Normal Renin Level 85

85 A BETTER BENCHMARK such compensation, for Na, is the activation of the RAAS mechanism, which becomes operative at Na intakes at or below ~3000 mg/d for an adult using that criterion, Na intakes < 3000 mg would be deficient in other words, without compensation individuals would have hypotension and/or hypovolemia 86

86 A BETTER BENCHMARK the NaCl requirement in patients with RAAS disabled is the intake that maintains BP without compensatory adjustments 87

87 A BETTER BENCHMARK the NaCl requirement in patients with with RAAS disabled is the intake that maintains BP without compensatory adjustments that s precisely the situation with Addison s disease (because those patients lack aldosterone) thus, the NaCl intake needed in pts. with adrenal insufficiency is arguably the best estimate of optimal for everybody 88

88 RISK RVE FOR BP LOWERING 5-yr nonconcurrent cohort study 398,419 hypertensive pts. at Kaiser SoCal risk of death &/or ESRD Sim et al., J Am Coll Cardiol 2014; 64: Adjusted Hazard Ratio < >170 Systolic Blood Pressure

89 CONCLUSIONS the risk curve for Na is the same as for other nutrients: U-shaped

90 CONCLUSIONS the risk curve for Na is the same as for other nutrients: U-shaped risk of harm rises at both extremes of intake

91 CONCLUSIONS the risk curve for Na is the same as for other nutrients: U-shaped risk of harm rises at both extremes of intake the lowest risk range seems to be at about the current U.S. average Na intake

92 CONCLUSIONS the risk curve for Na is the same as for other nutrients: U-shaped risk of harm rises at both extremes of intake the lowest risk range seems to be at about the current U.S. average Na intake there is no evidence to justify efforts to decrease average salt intake

93 CONCLUSIONS the risk curve for Na is the same as for other nutrients: U-shaped risk of harm rises at both extremes of intake the lowest risk range seems to be at about the current U.S. average Na intake there is no evidence to justify efforts to decrease average salt intake we should be emphasizing increasing Ca and K intakes, rather than decreasing Na intake

94 Questions? 95

95 NUTRI-BITES Webinar Series Sodium: Too much, too little or just right? Based on this webinar the participant will be able to: Review the evolution of sodium intake recommendations Understand the physiology related to regulating sodium metabolism Discuss latest findings of the association of sodium intake to health outcomes Outline practical dietary strategies dietitians can offer clients as the science on sodium evolves

96 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 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: A Decade of Nutrigenomics: What Does it Mean for Dietetic Practice? Ethics for All: Applying Ethics Principles across the Dietetics Profession Sports Nutrition: The Power to Influence Exercise Performance Culinary Competency to Enhance Dietetic Practice Nutrition and Oral Health: What Dietitians Should Know Lifestyle Approaches to the Prevention and Treatment of Diabetes

97 Next ConAgra Foods Science Institute Nutri-Bites Webinar Phytochemicals: Hidden Nutrition Gems Sylvia Escott-Stump, MA, RD, LDN Director, Dietetic Internship Department of Nutrition Science East Carolina University Date: January 15, pm EST/1-2 pm CST

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