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Salt, Hypertension


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Title: Salt, Hypertension

Salt, Hypertension Health
  • Presenters name
  • Institution

Hypertension A leading risk factor for
death and disability
Proportion of deaths attributable to leading risk
factors worldwide (WHO 2000)
Ezzati et al. WHO 2000 Report. Lancet.
Organ damage related to hypertension
Cerebrovascular disease - transient ischemic
attacks - ischemic or hemorrhagic stroke -
vascular dementia Hypertensive retinopathy Left
ventricular dysfunction Coronary artery
disease - myocardial infarction - angina
pectoris - congestive heart failure Chronic
kidney disease - hypertensive nephropathy
GFR lt 60 ml/min/1.73 m2) - albuminuria -
ESRD/dialysis Peripheral artery disease -
intermittent claudication
High blood pressure as a cardiovascular risk
  • Systolic blood pressure gt 115 mmHg causes
  • overall 50 of heart and stroke
  • 60-70 of strokes
  • Hypertension gt 140/90 mmHg causes
  • heart Failure 50
  • heart attack 25
  • kidney failure 20

Risk of hypertensionincreases with age
Risk of Hypertension
Risk of Hypertension
Years to Follow-up
Years to Follow-up
Future risk in normotensive women and men aged 65
JAMA. 2002 Framingham data.
Risk of stroke mortalityincreases with age
80-89 years

70-79 years
60-69 years
50-59 years
Systolic blood pressure (mm Hg)
Prospective Studies Collaboration. Lancet.
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

In summary
  • Hypertension is a leading risk factor for death
    and disability.
  • Hypertension is a major cardiovascular risk
  • Hypertension is very prevalent and has a large
    impact on health care resource use.
  • Lifestyle factors influence blood pressure
    including dietary salt.

Salt , Sodium Hypertension
Higher dietary salt increases death from stroke
in the EU
Adapted from Perry IJ et al. J Hum Hypertens.
High salt intake increases risk of death
He FJ, MacGregor GA. J Hum Hypertens.
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. 20037245-50.
Dietary salt ? blood pressurein animal research
Excess salt intake raises blood pressure in
Rats Pigs Mice Dogs Rabbits Chickens Baboons Chimp
anzees Green monkeys Spider monkeys
  • Such studies provide us
  • with detailed information
  • regarding how salt may
  • affect blood pressure
  • its time course
  • underlying mechanisms
  • what to expect in humans

Animal studies suggest
  • 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.

Van Vliet et al, 2006
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. 1994267H2471-82.
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.

Renal Mechanismsfor Salt-Dependent Hypertension
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 1464
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).

Factors that lead to salt sensitivity of blood
  • intrauterine growth retardation (IUGR)
  • low nephron mass
  • renal disease
  • inflammation, injury, etc
  • genetic abnormalities
  • exogenous agents (e.g. DOCA)
  • ageing - ? salt excretion

Evidence in Humans for a Link between High
Dietary Salt Hypertension
Lower salt reduces systolic blood pressure
He FJ, MacGregor GA. J Hum Hyptens.
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
  • gt920 mg/day reduction in dietary sodium
  • gt4 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. 2004Issue 1. Art. No. CD004937.
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. 2004Issue 1. Art. No. CD004937.
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
  • blood pressure lowered by 2.0/1.0 mm Hg

He FJ, MacGregor GA. Cochrane Database of Syst
Rev. 2004Issue 1. Art. No. CD004937.
Effects of salt reduction on blood pressure over
Obarzanek E et al. Hypertension. 200342459-67.
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. 20013443-10.
Results diet and salt intake
Intervention Change in mean blood pressure vs control (systolic) 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
DASH-Sodium Collaborative Research Group. N Engl
J Med. 20013443-10.
Salt restriction reduces blood pressurein
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. 200648861-9.
In summary
  • High dietary salt increases blood pressure,
    which is a health risk.
  • Lower salt consumption decreases blood
  • Other dietary factors can also reduce blood

The Importance of Lower Salt Intake
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

Can J Cardiol. 200723437-43.
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. 200824497-501.
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

BMJ. 2007334885-92.
Changes in diastolic blood pressure, salt intake
and stroke deaths in Finland
5600 mg
3360 mg
Karppanen H et al. Progress, Cardiovascular
Disease. 20064959-75.
Salt intake and obesity
  • High dietary salt increases thirst and fluid
  • 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
  • Therefore high salt diets are likely to be a
    significant factor in the obesity epidemic.

He FJ et al. Hypertension. 200851629-34.
Relationship between salt intake and fluid
consumption in children and adolescents
R0.40 plt0.001
He FJ et al. Hypertension. 200851629-34.
Salt and other health effects
  • obesity and related diseases (e.g. diabetes)
  • asthma
  • kidney stones
  • osteoporosis
  • gastric cancer

How much salt do we need ?
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
  • 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
Prevalence of excessive intakes What we eat in
America, NHANES 2001-2002
Where in our diet does salt come from?
In regions where most food is processed or eaten
in restaurants
  • 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. 199110383-93.
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.

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!

Our taste for saltwould we miss it ?
  • Taste buds get used to high salt levels.
  • As salt levels are gradually reduced taste buds
  • Only takes a few weeks to enjoy food with less
    salt and reveal subtle flavors.

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

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.

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.

Success stories for reducing dietary salt
  • Finland (1970)
  • Karppanen H, Mervaala E. Sodium intake and
    hypertension. Prog Cardiovasc Dis 2006 49
    5975 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 96570.
  • UK (1996)
  • Food Standards Agency
  • http//
  • CASH Consensus Action on Salt and Health
  • http//
  • WASH (2005) World Action on Salt and Health
  • http//

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

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
  • raising consumer attention to salt levels on food

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)

PAHO/WHO Cardiovascular Disease Prevention
through Dietary Salt Reduction
PAHO/WHO Cardiovascular Disease Prevention
through Dietary Salt Reduction
  • PAHO has established a Regional Experts Group
  • international leaders in nutrition and chronic
  • developed a policy statement
  • with a view to commitment and implementation by
  • who is willing to do what
  • what resources are required

  • 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.

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.

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.

  • 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

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.

  • 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
  • Develop legislative or regulatory frameworks to
    implement the WHO recommendations on advertising
    of food products and beverages to children.

To nongovernmental organizations, healthcare
organizations, associations of health
professionals, consumers associations
  • Endorse the PAHO dietary salt reduction policy
  • 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

  • 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.

To the food industry
  • Endorse the PAHO dietary salt reduction policy
  • 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
  • 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
  • Promote the health benefits of low salt diets to
    all peoples of the Americas.

  • 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
  • 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

  • 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
  • Assist Member States to revise national and
    subregional fortification programs to be
    consistent with efforts to reduce dietary salt.

  • 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.

Where can I get resources?
  • Hypertension website
  • Consensus Action on Salt Health (CASH)
  • World Action on Salt Health (WASH)
  • World Health Organization (WHO)
  • Pan American Health Organizaiton (PAHO)

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.
  • Sodium chloride, dietary adverse effects
  • Hypertension prevention and control
  • Iodine deficiency
  • Nutrition policy
  • National health programs organization and
  • World Health Organization
  • WHO Technical Meeting on Reducing Salt Intake in
    Populations (2006 Paris, France)
  • Title
  • ISBN 978 92 4 159537 7 (NLM classification
    QU 145)

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