1เกลือกับโรคความดัน หัวใจ และไต ผศ. นพ. สุรศักดิ์ กันตชูเวสศิริประธานอนุกรรมการป้องกันโรคไตเรื้อรังสมาคมโรคไตแห่งประเทศไทยสมสี้รี้Welcome to the 2010 APHA Webinar on sodium.CDC and APHA are excited about the opportunity of having you all join us.Today we will address sodium reduction as a public health imperative, as well as current sodium-reduction efforts at the local, State, national and international level.I am Darwin Labarthe (introduce self)And with me are Dr. Jonathan Fielding, Director of the LA County Health Department, who will provide an overview of the landscape of sodium activities.Dr. Lawrence Appel, Professor of Medicine at Johns Hopkins will share with you the recommendations of the newly released IOM report, Strategies to Reduce Sodium Intake in the United States.
2หัวใจวาย อัมพฤกษ์ อัมพาต ไตวาย ความดันโลหิตสูงทำให้เกิดโรคแทรกซ้อน The detection and treatment of high BP and its associated CVD risk should be a key focus of health-care policy, as patients with uncontrolled hypertension can develop serious complications in several end-organ systems, including blood vessels, heart, brain, kidneys and eyes. This diagram summarises some of the end-organ complications and consequences associated with persistent raised blood pressure. Untreated prolonged hypertension puts a strain on the arteries, arterioles and heart, and may have fatal consequences. The first sign of high blood pressure may be end-organ damage, due to damage of small arterioles within the organ.ไตวาย
3ความดันโลหิตสูงเพิ่มความเสี่ยงในการเกิดอัมพฤกษ์ อัมพาต Based on trial data n =190,000Stroke :1024*Registry data10 mmHg30% reduction in risk35% strokes*65% strokes*Clinical cut-off points do not reflect continuous relation between B.P. and health outcomes“Normotensives” get strokes too – key is to reduce population risk!10 mmHg reduction in systolic B.P. reduces individuals stroke risk by ~30%Mean systolic B.P. reductions of 5-10 mmHg are potentially achievable by reducing sodium consumption.3
10คำแนะนำสำหรับปริมาณโซเดียมที่ควรทานตามอายุ ปริมาณโซเดียมที่ควรทานต่อวัน (มิลลิกรัม)0-6 เดือน1207-12 เดือน3701-3 ปี10004-8 ปี1,2009-50 ปี1,50050-70 ปี1,300> 70 ปีThis is a table defining the Adequate Intake amounts for all age groups.Daily sodium intake should be targeted to these amounts.CMAJ 2008;179(12 Suppl):E1-E93 #2.1
11มีคนส่วนน้อยที่สามารถทานเกลือได้ตามที่กำหนด Met the 2005 DGA RecommendationAll Adults9.6%<2,300 mg/day Recommended18.8%≤1,500 mg/day Recommended5.5%With hypertension5.9%Aged 40 years and older without hypertension5.1%Black, aged 20–39 years5.7%When you look at sodium intake by Dietary Guidelines recommendation you see that most adults exceed their recommended limit, it is possible, about 10% meet the recommendation but the other 90% consume >1000 mg overSource: CDC NHANES unpublished data.
12แนวโน้มการเพิ่มขึ้นของการบริโภคเกลือโซเดียม Source: Briefel and Johnson (2004) for data; NHANES for data.
15ที่มาของเกลือโซเดียมในอาหาร อาหารสำเร็จรูปและภัตตาคาร 77% เป็นส่วนประกอบตามธรรมชาติ 12%As you can see from the table, sodium is already in the food we eat. Contrary to what many people think, the salt shaker is not the major contributorThe vast majority of sodium consumed, about 77 percent, comes from restaurant and processed foods. Only about 12 percent is naturally occurring in fruits, vegetables and whole grainsWhile some processed foods, such as cured meat or canned soups may be easily recognized as salty, many other processed and prepared foods are substantial sources of sodium because they are foods frequently consumed, such as bread and cereal.How do we know how much sodium is in our foods, is through analysis of foods and datasystems. Is critical that these are updated to reflect progress or lack of progress in reducing the sodium content of foodsExtra background information:(note – this slide draws from an older study with a small # of participants, there is nothing new available that captures salt added at the table or while cooking. We don’t have reason to believe this is off, and with less people cooking the contribution of sodium from processed and restaurant foods is likely greater)Sodium chloride is the chemical name for salt.Sodium is a component of salt; table salt is 40 percent sodium and 60 percent chloride. One level U.S. teaspoonful of salt contains approximately 6,200 mg sodium chloride (salt), or approximately 2,400 mg sodium.It is the sodium portion of salt that is important to people concerned about high blood pressure.The words “salt” and “sodium” are often used interchangeably although they are not exactly the same. For example, the Nutrition Facts Panel uses “sodium” while the front of the package may say “low salt.”Ninety percent of the sodium consumed is in the form of salt -Other sources include food additives such as baking soda. A small amount is naturally occurring in foods like fruits and vegetables.Salt is used by the food industry in every food category to enhance pleasant flavors and/or mask unpleasant flavors, as a preservative, for moisture retention and to provide bulk and uniformity in poultry.Some extra language:The presence of salt in the food supply has become ubiquitous. Prior to refrigeration, the benefits of salt outweighed the potential negative effects. However, after the advent of refrigeration this was reversed and the negative effects began to far outweigh any benefits it may offer. Salt is not just in foods one would think of as “salty” such as chips, pickles or cured meat. There is also a significant amount of salt in foods like cereal, bread and condiments. This is part of what makes sodium reduction so challenging.Source: Mattes RD, Donnelly, D. Relative contributions of dietary-sodium sources. J Am Coll Nutr Aug;10(4):383–93.
21นโยบายที่ช่วยลดการบริโภคเกลือโซเดียม รณรงค์ให้ความรู้ประชาชนขอความร่วมมือบริษัทผู้ผลิตลดปริมาณของเกลือในอาหารสำเร็จรูปมีป้ายแสดงปริมาณเกลือในเมนูอาหารมีป้ายแสดงปริมาณเกลือในฉลากอาหารสำเร็จรูปOur taste buds would adjust over time21
35Sodium Recommendation 2005 Dietary Guidelines for Americans (DGA) recommendation: <2,300 mg/day.“Specific populations” recommended to limit intake to 1,500 mg/day:HypertensivesBlacksMiddle-aged (40) or older Americans“Specific populations”: 70% of American adults.Average intake: 3,466 mg/day.Generally, higher consumption of salt means higher blood pressure.Sodium intake is related to levels of blood pressure, the incremental rise in blood pressure with age, and the prevalence of hypertension across populations.Within the span of a few weeks, most people experience a reduction in blood pressure when salt intake is reduced.Currently, however, less than 10% of all Americans limit their sodium intake to within dietary recommendations. Among the specific populations, only 5% meet this target.Source: Ayala C, et al. Application of lower sodium intake recommendations to adults—United States, 1999– MMWR Morb Mortal Wkly Rep. 2009;58(11):281–283.35
36Canadian Best Practice Recommendations for Stroke Care, updated 2008 2.1 Sodium:The recommended daily sodium intake from all sources is the Adequate Intake by age. For persons 9-50 years, the Adequate Intake is 1500 mg. Adequate Intake decreases to 1300 mg for persons years and to 1200 mg for persons > 70 years. A daily upper limit of 2300mg should not be exceeded by any age group.See for sodium intake guidelinesThe recommended amounts of sodium from all sources is found in the following table, but never to exceed 2300 mgCMAJ 2008;179(12 Suppl):E1-E93 #2.136
37Recommendations for Adequate Sodium Intake by Age Sodium Intake per Day (mg)0-6 months1207-12 months3701-3 years10004-8 years1,2009-50 years1,50050-70 years1,300> 70 yearsThis is a table defining the Adequate Intake amounts for all age groups.Daily sodium intake should be targeted to these amounts.CMAJ 2008;179(12 Suppl):E1-E93 #2.1
38High Blood Pressure: Major Component of Chronic Disease Risk Proportion of incidence due to high blood pressure (Systolic >115 mmHg)Stroke 70-75%Congestive Heart Failure 50%Ischemic Heart Disease 25%Renal Failure 20%High blood pressure is the leading cause of mortality worldwide Lancet :174738
39Sharp increase in sodium consumption: Source: Briefel and Johnson (2004) for data; NHANES for data.
40Main sources are commonest foods: The majority of sodium consumed, about 77%, comes from processed foodsSodium is already in the food we eat.It is difficult for people wanting or needing to reduce their sodium intake to do so.USDA Major Food CategoriesSource: CDC NHANES unpublished data.40
41Hypertension Detection and Management in Thailand 2005 (>15 years) 3rd NHES 2005.
44Salt (Sodium) and Hypertension Low consumption of fruits & vegetablesWeightLow exerciseAlcohol in excessA major driver in this increase in HTN is the sodium in our diet.The other factors listed here certainly are contributing factors but sodium is a key component.Evidence for excess alcohol contributing to high BP is less strong than for other factors.44
47A few are meeting the target daily intake: Met the 2005 DGA RecommendationAll Adults9.6%<2,300 mg/day Recommended18.8%≤1,500 mg/day Recommended5.5%With hypertension5.9%Aged 40 years and older without hypertension5.1%Black, aged 20–39 years5.7%When you look at sodium intake by Dietary Guidelines recommendation you see that most adults exceed their recommended limit, it is possible, about 10% meet the recommendation but the other 90% consume >1000 mg overSource: CDC NHANES unpublished data.
48Many purchasers do buy “Low Salt”: 47.3% of all shoppersFrequency of Buying “Low Salt” Items by GenderAlwaysOftenSometimesRarelyNeverDon’t Shop for FoodAll11.7%12.8%22.8%17.3%27.0%8.4%MaleFemale10.5%11.4%14.0%19.9%25.4%16.0%18.5%27.8%26.3%14.4%2.9%SOURCE: NHIS unpublished data.For example, The NHIS asks, About how often do you or the person who shops for your food buy items that are labeled “low salt” or “low sodium”? Would you say:AlwaysOftenSometimesRarelyNeverDon’t shop for foodWhile only a small portion are diligent in always purchasing “low salt” items, nearly half of the population has this issue on their radar to some degree.
49Thank You For More Information: CDC Sodium Web Page:Just a few – many moreThe findings and conclusions in this presentation are those of the author and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
50A Brief History…The Yellow Emperor’s Classic of Internal Medicine written in China over 2,000 years ago notes*:“Hence if too much salt is used for food, the pulse hardens”For millions of years daily sodium intake < 400 mg/day - genetically programmed levelRecent change to 3-4,000 mg/day - a major physiological challengeWe have known this for sometime now.Source:Veith, I. (Translator) The Yellow Emperor’s Classic on Internal Medicine. U of California Press, 2002.*Veith, I. (Translator) U of California Press, 2002.50
51Salt: Increasing the Pressure Mechanisms by which dietary sodium increases arterial pressure are not fully understoodHigh sodium fluid retention B.P.Kidneys excrete sodium fluid retention B.P. Prolonged high sodium intake may reset thresholds set by kidneys.Kidneys are less able to remove sodium as we age.Genes (14) responsible for Mendelian forms of hypo- or hypertension are all involved in renal sodium handling.Low dietary potassium renal sodium retention B.P.Signaling pathway in vasculature responds to sodium but does not regulate basal B.P. (Nat. Med :64).The detailed mechanisms of how sodium affects blood pressure are not fully understood but here are a couple of contributing factorsHigh sodium fluid retention B.P.Kidneys excrete sodium fluid retention B.P. Prolonged high sodium intake may reset thresholds determined by kidneys. (since this process is continually cycling, thresholds get reset by kidneys)Kidneys are less able to remove sodium as we age. (unsure of why this is)Genes (14) responsible for Mendelian forms of hypo- or hypertension are all involved in renal sodium handling. (validating that sodium plays a key role in BP)Low dietary potassium renal sodium retention B.P.Signaling pathway in vasculature responds to high sodium but does not regulate basal B.P. (Nat. Med :64). (there are specific mechanisms at the vascular level for recognizing sodium)51
52Sodium and Blood Pressure Evidence:Animal studiesHuman Genetic StudiesEpidemiological StudiesMigration studiesInterventional StudiesTreatment StudiesThere are numerous studies in the literature to link sodium to BP52
53Animal Studies Chimps: 2 groups of 13 (age 5-18y) *Nature Med 1995; 1:Chimps: 2 groups of 13 (age 5-18y)Control group usual veg. & fruit diet, low Na+,high K+Intervention group fed increasing amounts of salt over 84 weeksInterventionChange in mean B.P. vs. controls5g/d 19 weeks+12 mmHg (systolic)10g/d 3 weeks, 15g/d 36 weeks+26 mmHg15g/d 26 weeks+33 mmHg0g/d 20 weeksControl levelsFor instance a study of chimps (evolution close to humans) were studied to see the effects of sodium on BP.Control group chimps ate their normal diet of veggies & fruit (low in sodium) while the intervention group was fed increasing amounts of salt over time.The results are astounding.The intervention group developed HTN at rate correlated to increasing amounts of ingested sodium. When taken off the sodium the BP returned to control levels.Note: Second study involved chimps with high BP, old, and overweight animals.Similar study (127 chimps) finds effect of Na+ on B.P. persists over 2 year time course (Circulation :1563).53
54Treatment Study: DASH Sodium -7Randomized 412 adults (mixed B.P. status, racial groups, sexes) to:Control diet - low in fruit, veg and dairy, fat content typical of USDASH diet - high in fruit, veg and low-fat dairy, reduced fat contentConsume diet for consecutive 30 day periods in random order at each of 3 levels of saltInterventionChange in mean B.P. vs. control (systolic)Control dietDASH diet9g/d saltControl level- 6 mmHg6g/d salt- 2 mmHg- 7 mmHg3g/d salt- 9 mmHg-7 (NT)-11(HT)Similar study with humans, in two groups (one eating a typical NA diet and one eating according to the DASH diet).Both groups added 3 specific levels of salt to their diet.The results in change of BP were telling. When the sodium in their diet was decreased, BP fell in both groups.The group eating according to the DASH diet had an even greater reduction in BP.Interestingly those the HTN group had their BP affected even more.NEJM 2001; 344:3-1054
55Blood Pressure and Stroke Based on trial data n =190,000Stroke :1024*Registry data10 mmHg30% reduction in risk35% strokes*65% strokes*Clinical cut-off points do not reflect continuous relation between B.P. and health outcomes“Normotensives” get strokes too – key is to reduce population risk!10 mmHg reduction in systolic B.P. reduces individuals stroke risk by ~30%Mean systolic B.P. reductions of 5-10 mmHg are potentially achievable by reducing sodium consumption.55
56Blood Pressure and Stroke -7Clinical cut-off points do not reflect continuous relation between B.P. and health outcomes“Normotensives” get strokes too – key is to reduce population risk!10 mmHg reduction in systolic B.P. reduces individuals stroke risk by >30%Mean systolic B.P. reductions of 5-10 mmHg are potentially achievable by reducing sodium consumption.-756
57Sodium (salt) in our Diet Natural~15%Discretionary~15%Manufactured food processing~70%Health Minimum180 mg/dReference Standard**2,400 mg/d (6.1 g salt)Adequate Intake*1,500 mg/d (3.8 g salt)Tolerable Upper Intake*2,300 mg/d (5.8 g salt)This slide shows key values of salt in our diet.15% of the salt in our diet comes from natural sources. Another 15% is added by us (discretionary). The remaining 70% comes from the processed foods that we eat.There is a huge disparity between what we need and what we are getting:Sodium is essential for life. The health minimum is 180 mg/d. Tolerable upper limit is 2300 mg/dReference standard is outdated at 2400 mg/d. The recommended daily amount is 1500 mg/d yet the reference standard still exists on all our labels.3,000 – 4,000 mg/d (8-10 g salt)*Health Canada. Dietary Ref. Intake Reports**2003 labeling legislation57
58Public Health Impact ~1,500 mg/day (AI) BP ~5 mmHg ~3,500 mg/day (current)~1,500 mg/day (AI)BP ~5 mmHgDecrease hypertension prevalence by 30% (CJC :437)Prevent 30 premature deaths per day from Stroke and IHD, ~15% all CV events (CJC :497)Likely positive impact on obesity, osteoporosis, stomach cancer, kidney disease, asthma, etc…It has been calculated that if we reduce our sodium intake from 3500 mg/day to 1500 mg/d we will have a reduction in BP = approximately 5 mmHG.This reduction BP will have an impact on the # people with HTN, cardiovascular events and positive impacts on many other disease processes according to the literature.58
59Sodium in our Food: Hard to Avoid Food (CCHS 2004 data)%Pizza, sandwiches, subs, burgers, hot dogs*19.1Soups7.4Pasta5.7Liquid milk products4.0Poultry and poultry dishes3.8Potatoes3.4Cheese3.2Cereals3.0Do these numbers surprise you?Think of what you eat in a day and it is easy to understand how we ingest so much sodium.It is hard to avoid*Breads14.059
62Sodium in our Food: Why?$ Cheap way to boost flavor, texture and shelf life of poor quality foods$ Salt and sodium phosphates increase water binding capacity of meat products$ Salty snacks make you thirsty!$Food – (fiber, nutrients, flavor) + (salt, sugar, fat) = $$Processed food62
63Sodium in our Food: Would we miss it? Taste buds are used to high salt levelsAs salt levels are gradually reduced taste buds become more sensitiveStudies have shown that it only takes a few weeks to enjoy food with less salt and reveal subtle flavorsOur taste buds would adjust over time63