Salt, Hypertension

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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.
20023601347-60.
5
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
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High blood pressure as a cardiovascular risk
factor

• 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

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Risk of hypertensionincreases with age
Risk of Hypertension
Risk of Hypertension
100
100
Women
Men
80
80
60
60
40
40
20
20
0
0
Years to Follow-up
Years to Follow-up
Future risk in normotensive women and men aged 65
years
JAMA. 2002 Framingham data.
8
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.
20023601903-13.
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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.
1992623-25.
13
High salt intake increases risk of death
He FJ, MacGregor GA. J Hum Hypertens.
200216761-70.
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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. 20037245-50.
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Dietary salt ? blood pressurein animal research
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Excess salt intake raises blood pressure in
animals
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

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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
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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. 1994267H2471-82.
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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 1464
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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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Factors that lead to salt sensitivity of blood
pressure

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

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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
He FJ, MacGregor GA. J Hum Hyptens.
200216761-70.
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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
• 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.
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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. 2004Issue 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. 2004Issue 1. Art. No. CD004937.
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Effects of salt reduction on blood pressure over
time
Obarzanek E et al. Hypertension. 200342459-67.
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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. 20013443-10.
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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.
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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.
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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. 200723437-43.
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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. 200824497-501.
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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. 2007334885-92.
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Changes in diastolic blood pressure, salt intake
and stroke deaths in Finland
5600 mg
3360 mg
DBP
Salt
Stroke
Karppanen H et al. Progress, Cardiovascular
Disease. 20064959-75.
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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. 200851629-34.
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Relationship between salt intake and fluid
consumption in children and adolescents
R0.40 plt0.001
He FJ et al. Hypertension. 200851629-34.
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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?
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.
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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 saltwould 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
  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//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
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
  administration
• 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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Resources
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