1 salt, hypertension & health presenters name institution
TRANSCRIPT
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Salt, Hypertension & Health
Presenters name
Institution
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Outline
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Hypertension:
A leading risk factor for death and disability
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Proportion of deaths attributable to leading risk factors worldwide (WHO 2000)
Ezzati et al. WHO 2000 Report. Lancet. 2002;360:1347-60.
Attributable Mortality (In millions; total 55,861,000)
0 87654321
High blood pressure
Tobacco
High cholesterol
Unsafe sex
High BMI
Physical inactivity
Alcohol
Indoor smoke from solid fuels
Iron deficiency
Underweight
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Organ damage related to hypertensionCerebrovascular disease
- transient ischemic attacks- ischemic or hemorrhagic stroke- vascular dementia
Hypertensive retinopathyLeft ventricular dysfunctionCoronary artery disease
- myocardial infarction- angina pectoris- congestive heart failure
Chronic kidney disease- hypertensive nephropathy GFR < 60 ml/min/1.73 m2)- albuminuria- ESRD/dialysis
Peripheral artery disease- intermittent claudication
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High blood pressure as a cardiovascular risk factor
• Systolic blood pressure > 115 mmHg causes:• overall 50% of heart and stroke• 60-70% of strokes
• Hypertension > 140/90 mmHg causes:• heart Failure 50%• heart attack 25%• kidney failure 20%
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Risk of hypertensionincreases with age
Risk of Hypertension %
0 2 4 6 8 10 12 14 16 18 20
Years to Follow-up
Women
Risk of Hypertension %
Years to Follow-up
0 2 4 6 8 10 12 14 16 18 20
Men
JAMA. 2002: Framingham data.
100
80
60
40
20
0
100
80
60
40
20
0
Future risk in normotensive women and men aged 65 years
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Risk of stroke mortalityincreases with age
Systolic blood pressure (mm Hg) Prospective Studies Collaboration. Lancet. 2002;360:1903-13.
80-89 years
70-79 years
60-69 years
50-59 years
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Lifestyle risk factors for hypertension
• high dietary salt intake
• obesity
• high alcohol intake
• physical inactivity
• smoking
• inadequate vegetable and fruit intake
• inadequate milk product intake
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In summary
• Hypertension is a leading risk factor for death and disability.
• Hypertension is a major cardiovascular risk factor.
• Hypertension is very prevalent and has a large impact on health care resource use.
• Lifestyle factors influence blood pressure including dietary salt.
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Salt , Sodium & Hypertension
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Higher dietary salt increases death from stroke in the EU
Adapted from Perry IJ et al. J Hum Hypertens. 1992;6:23-25.
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High salt intake increases risk of death
CHDDeath
CVDDeath
AllDeath
1.75
1.50
1.25
1.00
0.75
0.50
Haz
ard
Rat
io
High saltHigh saltintakeintake
Lower saltLower saltintakeintake
He FJ, MacGregor GA. J Hum Hypertens. 2002;16:761-70.
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International scientific and health organizations conclude that high
dietary salt:
• increases blood pressure• is a health risk
WHO/FAO technical report recommends less than 5 g of salt per day
Nishida C et al. Public Health Nutr. 2003;7:245-50.
WHO/FAO technical report recommends less than 5 g of salt per day
Nishida C et al. Public Health Nutr. 2003;7:245-50.
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Dietary salt blood pressurein animal research
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Excess salt intake raises blood pressure in animals
RatsPigsMiceDogsRabbitsChickensBaboonsChimpanzeesGreen monkeysSpider monkeys
Such studies provide uswith detailed informationregarding how salt mayaffect blood pressure
• its time course• underlying mechanisms• what to expect in humans
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Animal studies suggest:
Van Vliet et al, 2006
• Excess salt intake can cause a slow and progressive increase in blood pressure.
• In time, salt restriction may not fully restore blood pressure to original levels.
• Acute salt restriction may underestimate the accumulated effects of lifelong salt exposure.
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Excess salt intake increases morbidity and mortality in animals
Morbidities•cardiac hypertrophy•vascular hypertrophy•vascular stiffening• renal damage•hyperlipidaemia• insulin resistance
Mortality •hypertensive encephalopathy•stroke•heart failure•premature death
Progressive (left to right) effect of salt exposure on LVH in salt sensitive (DS, top row) vs salt resistant (DR, bottom row) rats.
From Inoko Am J Physiol. 1994;267:H2471-82.
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Animal studies summary
• The ability of excess salt to raise blood pressure appears to be a general characteristic in mammals, including humans.
• The effects of salt on blood pressure are complex, having several distinct components:- acute vs slow-progressive;- reversible vs irreversible.
• Many individual systems and mechanisms contribute to the effect of salt on blood pressure.
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Renal Mechanismsfor Salt-Dependent
Hypertension
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Renal mechanisms forsalt-dependent hypertension
• Acute high salt intake- renal retention of fluid blood pressure
• Chronic high salt intake- resets renal threshold for salt excretion less salt
excretion- peripheral resistance- subnormal vasodilation to salt load
Nat. Med. 2008 14:64
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Acute salt sensitivity of blood pressure
Salt sensitivity is well defined by the steady state relationship between salt intake and blood pressure (“chronic pressure natriuresis relationship”, or “renal function curve”).
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• intrauterine growth retardation (IUGR)• low nephron mass• renal disease
inflammation, injury, etc• genetic abnormalities• exogenous agents (e.g. DOCA)• ageing - salt excretion
Factors that lead to salt sensitivity of blood pressure
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Evidence in Humans for a Link between
High Dietary Salt & Hypertension
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Lower salt reduces systolic blood pressure
4
2
0
-2
-4
-6
-8
-10
-12
-30 -50 -70 -90 -110 -130Change in Urinary Salt
(mmol/24h)
Cha
nge
in S
ysto
lic B
lood
Pre
ssur
e(m
mH
g)
Normotensives
Hypertensives
He FJ, MacGregor GA. J Hum Hyptens. 2002;16:761-70.
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Effect of longer-term modest salt reduction on blood pressure: meta-analysis*
Cochrane Review criteria for sodium studies to include in analysis: • random allocation of subjects to treatment/control groups• >920 mg/day reduction in dietary sodium • >4 weeks duration • no concomitant interventions
Hypertensive subjects (20 trials), median age 50 (range 24-73)
Normotensive subjects (11 trials), median age 47 (range 22-67)
* He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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Lower dietary salt reduced blood pressure in hypertensive adults
• 20 trials, 802 individuals
• dietary salt lowered by 4.5 g/day– from baseline of 7 - 11 g/d to 3.25 – 7.2 g/d
• blood pressure lowered by 5.1/2.7 mm Hg
He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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Lower dietary salt reduces blood pressure in normotensive adults
• 11 trials, 2,220 subjects
• dietary salt lowered by 4.25 g/day– from baseline of 7.25 – 11.5 g/d to 3.25 – 7.75 g/d
• blood pressure lowered by 2.0/1.0 mm Hg
He FJ, MacGregor GA. Cochrane Database of Syst Rev. 2004;Issue 1. Art. No.: CD004937.
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Effects of salt reduction on blood pressure over time
Obarzanek E et al. Hypertension. 2003;42:459-67.
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Lower salt as part of a healthy diet
Methodology• randomized 412 adults (mixed blood pressure status, racial groups, sexes) to:
• control diet - low in fruit, vegetables and dairy, fat content typical
of US diet
• DASH diet - high in fruit, vegetables and low-fat dairy, reduced fat content
• consume diet for consecutive 30 day periods in random order at each of 3 levels of salt
DASH-Sodium Collaborative Research Group. N Engl J Med. 2001;344:3-10.
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Results: diet and salt intake
DASH-Sodium Collaborative Research Group. N Engl J Med. 2001;344:3-10.
Intervention Change in mean blood pressure vs control (systolic)
Control diet DASH diet
9 g/d salt control level - 6 mmHg
6 g/d salt - 2 mmHg - 7 mmHg
3 g/d salt - 7 mmHg - 9 mmHg
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Salt restriction reduces blood pressure
in children and infants
• Children (average age 13) reduced dietary salt 42% reduced blood pressure 1.17/1.29 mmHg
• Infants (less than one year) reduced dietary salt 54% reduced systolic blood pressure 2.47 mmHg
Hypertension. 2006;48:861-9.
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In summary
• High dietary salt increases blood pressure, which is a health risk.
• Lower salt consumption decreases blood pressure.
• Other dietary factors can also reduce blood pressure.
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The Importance of Lower Salt Intake
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Healthcare cost savings in Canadaby reducing dietary sodium
Using the Cochrane Review data • a reduction in average dietary sodium intake by
4.5g/d (from 8.8g to 4.3g in Canada) would result in– 30% fewer people with hypertension– almost double the blood pressure treatment and control
rate– hypertension care cost savings of $430 to $538 million/yr
Can J Cardiol. 2007;23:437-43.
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Impact of reducing blood pressure
through dietary sodium• Annual reduction in incidence of
– myocardial infarction (5%) – strokes (13%) – heart failure (17%)
• Reduction in health care costs associated with the overall predicted 8.6% reduction in CVD– $1.7 billion per year in Canada and $18 billion in
the United States
Can J Cardiol. 2008;24:497-501.
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Observed effect of lower saltintake on cardiovascular events in
TOHP trials
• 25-30% lower risk of cardiovascular events in those who had been in the low salt groups
• 1.9 -2.5 g/day reduction in dietary salt during intervention
BMJ. 2007;334:885-92.
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Changes in diastolic blood pressure, salt intake and stroke deaths in Finland
5600 mg
3360 mg
DBP Salt StrokeKarppanen H et al. Progress, Cardiovascular Disease. 2006;49:59-75.
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Salt intake and obesity
• High dietary salt increases thirst and fluid consumption.
• Many of the fluids consumed contain simple sugars or alcohol and contribute to caloric intake.
• 20-30% of the excess calories consumed by children and adolescents are through increased beverage consumption associated with high salt intake.
• Therefore high salt diets are likely to be a significant factor in the obesity epidemic.
He FJ et al. Hypertension. 2008;51:629-34.
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Relationship between salt intake and fluid consumption in children and adolescents
R=0.40p<0.001
He FJ et al. Hypertension. 2008;51:629-34.
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Salt and other health effects
• obesity and related diseases (e.g. diabetes)• asthma• kidney stones• osteoporosis• gastric cancer
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How much salt do we need ?
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Dietary salt intake for adults
• In Canada and the USA – 3.25 - 3.75 g/day (age dependant) is estimated to
be adequate for most adults (adequate intake (AI))– 5.75 g/day is above the upper limit recommended
for health (upper limit (UL))• WHO/FAO technical report has indicated dietary salt
intake should be less than 5 g/day
DRI, IM 2003
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Prevalence of excessive intakes: What we eat in America, NHANES 2001-2002
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Where in our diet does salt come from?
• 12% natural content of foods
• “hidden” salt: 77% from processed food – manufactured and restaurants
• “conscious” salt: 11% added at the table (5%) and in cooking (6%)
J Am College of Nutrition. 1991;10:383-93.
11%
12%
77%
Occurs Naturally in Foods
Added at the Table or in Cooking
Restaurant/Processed Food
In regions where most food is processed or eaten in restaurants
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Where in our diet does salt come from?
• In regions where most food is prepared and eaten at home, large amounts of salt may be added in cooking or at the table.
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Salt in our food: why?
• boosts flavor, texture and shelf life of foods
• salt and sodium phosphates increase water binding capacity of meat products
• salty snacks make you thirsty!
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Our taste for salt:would we miss it ?
• Taste buds get used to high salt levels.
• As salt levels are gradually reduced taste buds adapt.
• Only takes a few weeks to enjoy food with less salt and reveal subtle flavors.
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In summary
In the Americas, people consume an unhealthy amount of salt.
This can cause hypertension, a leading risk for death and disability.
The solution is to reduce salt in commercially manufactured food and promote healthy eating.
We need to educate the public and patients. We need to provide leadership in our communities. The outlook for improvement is cautiously optimistic.
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Key messages
Dietary salt is an important contributor to high blood pressure.
Reducing salt lowers blood pressure and prevents cardiovascular disease.
Salt intake in the Americas is higher than the levels recommended for health.
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Key messages
Policies to reduce population-wide salt intake are most effective and can have a high impact.
Healthcare professionals can play a key role in educating people of all ages regarding their optimal dietary salt intake.
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Success stories for reducing dietary salt
• Finland (1970)– Karppanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis 2006;
49: 59–75; Laatikainen T et al. Sodium in the Finnish diet: 20-year trends in urinary sodium excretion among the adult population. Eur J Clin Nutr 2006; 60: 965–70.
• UK (1996)– Food Standards Agency
• http://www.food.gov.uk/healthiereating/salt/
– CASH – Consensus Action on Salt and Health• http://www.actiononsalt.org.uk/
• WASH (2005) –World Action on Salt and Health
– http://www.worldactiononsalt.com/
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Global initiatives
Success of WASH raising public, political and manufacturers’ awareness
WHO Technical Meeting statement on “Reducing salt intake in populations”
Agreement of major global food and beverage manufacturers to cut salt in their foods products
World Hypertension Day 2009 theme “Salt and Hypertension” – a massive global public health campaign to reduce dietary salt through a variety of initiatives including food sector and other stakeholders’ participation
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Reducing salt intake
• Most dramatic impact will be to reduce hidden salt in manufactured foods
• Reduction can be achieved by– gradual reduction of salt by food manufacturers
and restaurateurs– a public campaign on health benefits of salt
reduction– raising consumer attention to salt levels on food
labels
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Anticipated outcomes
• increased consumer awareness of the health dangers of high dietary salt
• increased consumer demand for lower salt foods
• increased development of lower salt foods by the food sector
• increased government monitoring of dietary salt as a health parameter
• gradual reduction in dietary salt such that most people are below the upper limit (by 2020)
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PAHO/WHO Cardiovascular Disease Prevention
through Dietary Salt Reduction
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PAHO/WHO Cardiovascular Disease Prevention
through Dietary Salt Reduction
• PAHO has established a Regional Experts Group– international leaders in nutrition and chronic
diseases– developed a policy statement– with a view to commitment and implementation by
stakeholders• who is willing to do what• what resources are required
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Policy GoalA gradual and sustained drop in dietary salt intake to reach national targets or the internationally recommended target of less than 5g/day/person by 2020.
Recommendations for Policy and Action• Consistent with the three pillars for successful dietary salt reduction
published by WHO: product reformulation; consumer awareness and education campaigns; and environmental changes to make healthy choices the easiest and most affordable options for all people.
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To national governments
• Seek endorsement for the PAHO dietary salt reduction policy statement from ministries of health, agriculture and trade, from food regulatory agencies, national public health leaders, non-governmental organizations, academia, and relevant food industries.
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To national governments
•Develop sustainable, securely funded, scientifically based salt reduction programs that are integrated into existing food, nutrition and health education programs. The programs should be socially inclusive and include major socioeconomic, racial, cultural, gender and age subgroups and specifically children. Components should include: – Standardized food labels that easily identify high and
low salt foods.– Educating people including children about the health
risks of high dietary salt and how to reduce salt intake
as part of a healthy diet.
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To national governments
• Initiate collaboration with relevant domestic food industries to set gradually decreasing targets, with timelines, for salt levels according to food categories, by regulation or through economic incentives or disincentives with government oversight.
• Regulate or otherwise encourage domestic and
multinational food enterprises to adopt a) best in class (salt content to match the lowest in the specific food category) and b) best in world (salt content to match the lowest in a specific food produced by the company elsewhere in the world) formulations for products in national markets.
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To national governments
• Develop a national surveillance system with regular reporting of dietary salt intake levels and the major sources of dietary salt. Monitor progress towards reducing intake to the reach the international target or a national one.
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To national governments
• Review national salt fortification policies and recommendations to be in concordance with the recommended salt intake.
• Extend official support to the Codex Alimentarius Committee on Food Labeling for salt/sodium to be included as a mandatory component of nutrition labels.
• Develop legislative or regulatory frameworks to implement the WHO recommendations on advertising of food products and beverages to children.
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To nongovernmental organizations, healthcare organizations, associations of health professionals, consumers’ associations• Endorse the PAHO dietary salt reduction policy
statement. • Educate memberships on the health risks of high
dietary salt and how to reduce salt intake. Encourage involvement in advocacy. Monitor and promote presentations on dietary salt at national meetings and the publication of articles on dietary salt reduction.
• Promote and advocate media releases on dietary salt reduction to reach the public, including children and particularly women given their integral roles in family health and food preparation.
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To nongovernmental organizations, healthcare organizations, associations of health professionals, consumers’ associations
• Broadly disseminate relevant literature. • Educate policy and decision makers on the health
benefits of lowering blood pressure among normotensive and hypertensive people, regardless of age.
• Advocate policies and regulations that will contribute to population-wide reductions in dietary salt.
• Promote coalition-building, increase organizational capacity for advocacy and develop advocacy tools to promote civil society actions.
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To the food industry• Endorse the PAHO dietary salt reduction policy statement.
• Make current best in class and best in world low salt products and practices universal across global markets as soon as possible. Make salt substitutes readily available at affordable prices.
• Institute reformulation schedules for a gradual and sustained reduction in the salt content of all existing salt-containing food products, restaurant and ready-made meals to contribute to achieving the policy goal. Make all new food product formulations inherently low in salt.
• Use standardized, clear and easy-to-understand food labels that include information on salt content.
• Promote the health benefits of low salt diets to all peoples of the Americas.
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To PAHO • Ensure good communications and information sharing between
regional and international initiatives to foster best practices. • Develop a template for national report cards and report to Member
States on comparative national baselines and progress at pre specified time points (e.g. in 2010 the baseline, progress in 2015 and 2020).
• Work with Member States to monitor dietary salt consumption. • Develop and foster a network of endorsing governments, NGOs, and
expert champions on dietary salt in the region.• Develop a web based ‘toolbox’ with educational materials and
programs on dietary salt for the public, patients, healthcare professionals that are culturally appropriate to subregions of the Americas.
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To PAHO
• Develop and advocate conflict of interest guidelines to assist health organizations and scientists in the region in their interactions with the food industry.
• Foster research on the economic and health impacts of high dietary salt in the countries and sub-regions.
• Assist Member States to revise national and subregional fortification programs to be consistent with efforts to reduce dietary salt.
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To PAHO
• Collaborate with FAO, UNICEF, the Codex Alimentarius Commission and other relevant UN bodies to achieve a consistent and coordinated approach to reducing dietary salt.
• Educate policy and decision-makers on the health benefits of lowering blood pressure among normotensive and hypertensive people, regardless of age.
• Advocate policies and regulations that will contribute to population-wide reductions in dietary salt.
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Where can I get resources?• www.lowersodium.ca
• www.sodium101.ca
• Hypertension website
• www.hypertension.ca
• Consensus Action on Salt & Health (CASH)
• www.actiononsalt.org.uk
• World Action on Salt &Health (WASH)
• www.worldactiononsalt.com/
• World Health Organization (WHO)
• www.who.int/dietphysicalactivity/reducingsalt/en
• Pan American Health Organizaiton (PAHO)
• www.paho.org/cncd_cvd/salt
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Resources
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Resources
1. Sodium chloride, dietary – adverse effects2. Hypertension – prevention and control3. Iodine – deficiency4. Nutrition policy5. National health programs – organization and administration
I. World Health OrganizationII. WHO Technical Meeting on Reducing Salt Intake in Populations (2006: Paris, France)III. Title
ISBN 978 92 4 159537 7 (NLM classification: QU 145)
WHO Forum on Reducing Salt Intake in Populations (2006: Paris, France)Reducing salt intake in populations: Report of a WHO Forum and Technical Meeting. 5-7 October 2006, Paris, France.
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Resources
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