Transcript Hypertension and Salt A call to action

Excess Dietary Sodium:
Impact on Hypertension and Health Outcomes
ADDITIONAL SLIDES
Updated 2011
1
The physiology of sodiummediated hypertension: a primer
2
Animal studies suggest:
• Excess sodium intake can
cause a slow and progressive
increase in BP.
• In time, sodium restriction may
not fully restore BP to original
levels.
• Acute sodium restriction may
underestimate the accumulated
effects of lifelong sodium
exposure.
Van Vliet et al, 2006
3
Animal studies: summary
1. The ability of excess sodium to
raise BP is a general
characteristic of mammals,
including humans.
2. The effects of sodium on BP are
complex, having several distinct
components:
- Acute vs Slow-Progressive
- Reversible vs Irreversible
3. Many individual systems and
mechanisms contribute to the
effect of sodium on BP.
4
Renal mechanisms for
sodium-dependent hypertension
• Acute high sodium intake
- Renal retention of fluid   BP
• Chronic high sodium intake
- Resets renal threshold for sodium excretion
less sodium excretion
-  Peripheral resistance
- Subnormal vasodilation to sodium load
Nat. Med. 2008 14:64
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Sodium sensitivity of BP
sodium sensitivity is
well defined by the
steady state
relationship between
sodium intake and BP
(“chronic pressure
natriuresis relationship”,
or “renal function
curve”).
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Factors that lead to sodiumsensitivity of blood pressure
• Intrauterine growth retardation (IUGR)
• Low nephron mass
• Renal disease
 Inflammation, injury, etc
• Genetic abnormalities
• Exogenous agents (e.g. DOCA)
• Ageing
•  sodium excretion
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Sodium 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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Average “hidden" sodium Intake
by provinces
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Sodium usual intake distribution for men and women
0.0008
AI=
1500
Relative probability density
0.0007
• Results are based on the Canadian
UL=
2300
Community Health Survey - Cycle 2.2 on
Nutrition, Statistics Canada, 2004.
Women
19-30y
0.0006
Usual intake distributions were estimated
•using
the Software for Intake Distribution
Estimation (SIDE), Iowa State University, 1986
0.0005
Women
31-50y
0.0004
Men
19-30y
0.0003
+
Men
31-50y
0.0002
0.0001
0
0
1000
2000
4000
3000
5000
6000
7000
8000
Sodium (mg/d)
Age
(y)
Men
Women
% above AI
% above UL
% above AI
% above UL
19 to 30
100
98.8
99.1
74.5
31 to 50
99.5
92.2
96.9
70.8
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The sodium intake of most Canadians
adults exceeds the UL
% above UL
100
80
60
Male
Female
40
20
0
19 to 30 31 to 50 51 to 70
Upper Limit 2300
2300
2300
71 or
older
2300
Health Reports, Vol. 18, No 2, May 2007
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Hidden sodium intake and
salt added at the table
“Hidden“ sodium intake
*
3,396
3,182
*
3,074
2,927
Never
Rarely
Occasionally
Very often
Add salt to food at table
* Average “ hidden” sodium intake
Health Reports, Vol. 18, No 2, May 2007
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Salt use by hypertensive adults
40
*
% of respondents
36
30
30
32
Canadians age >30 years
diagnosed with
high blood pressure
30
25
*
19
20
Yes
No
* 16
13
10
Never
Rarely Occasionally Very often
Add salt to food at table
Health Reports, Vol. 18, No 2, May 2007
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Sodium and Blood Pressure: Intersalt
BMJ. 1988 July 30; 297(6644): 319–328
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Relationship between sodium intake and
fluid consumption in children/adolescents
R=0.40
p<0.001
He et al Salt Intake, Soft Drinks, and Obesity in Children, Hypertension. 2008;51:629-634
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Sodium in our Diet
Natural Discretionary
~15%
~15%
Manufactured food processing
~70%
Reference Standard**
Adequate Intake*
1,500 mg/d (3.8 g salt) 2,400 mg/d (6.1 g salt)
Tolerable Upper Intake*
2,300 mg/d (5.8 g salt)
3,000 – 4,000 mg/d (8-10 g salt)
*Health Canada. Dietary Ref. Intake Reports
**2003 labeling legislation
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The sodium intake of most Canadian
children/youth exceeds the UL
% above UL
100
80
60
Male
Female
40
20
0
1 to 3
4 to 8
Upper Limit 1500mg 1900
9 to 13
14 to 18
2200
2200
Health Reports, Vol. 18, No 2, May 2007
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Av. Sodium Intake* (mg/day)
of Canadian Children and Youth
4500
4000
3500
3000
2500
2000
1500
1000
500
0
1-3 yr
Male
4-8 yr 9-13 yr
Female
*Does not
14-18 include sodium
added at the
yr
table or during
home cooking
M&F
Ref: Canadian Community Health Survey, Nutrition Survey
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The sodium intake of most Canadian children/youth
exceeds the UL
% above UL
100
80
60
Male
Female
40
M&F
20
0
1-3 yr
1500mg
4-8 yr
1900
9- 13yr
2200
14-18 yr
2300 Upper Level
Health Reports, Vol. 18, No 2, May 2007
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Sodium restriction reduces BP
in children and infants
Meta-analysis Results:
•Children (average age 13)
Reduced dietary sodium 42%
Reduced BP 1.17/1.29 mmHg
• Infants (less than one year)
 Reduced dietary sodium 54%
 Reduced SBP 2.47 mmHg
Hypertension 2006;48:861-9
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High sodium intake may also be a
risk factor for obesity!
• High dietary sodium 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 sodium intake
• Therefore high sodium diets are likely to be a
significant factor in the obesity epidemic
He et al Salt Intake, Soft Drinks, and Obesity in Children, Hypertension. 2008;51:629-634
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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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Deaths (millions)
Sodium reduction interventions are as
effective as smoking cessation interventions
in saving lives
8
7
6
5
4
3
2
1
0
13.8
8.5
5.5
Men
Women
Combined Intervention Intervention
package of to reduce
to control
intervention sodium tobacco use
intake
The Lancet, Volume 370, Issue 9604, 2044-2053, December 2007
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Deaths averted by implementation of
tobacco and sodium interventions
by type of diseases
80
75,6%
Deaths (%)
70
60
50
40
30
15,4%
20
8,7%
10
0
Cardiovascular
diseases
Respiratory
diseases
Cancer
The Lancet, Volume 370, Issue 9604, 2044-2053, December 2007
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-7
Treatment Study: DASH Sodium
Randomized 412 adults (mixed B.P. status, racial groups, sexes) to:
• Control diet - low in fruit, veg and dairy, fat content typical of US
• DASH diet - high in fruit, veg and low-fat dairy, reduced fat content
• Consume diet for consecutive 30 day periods in random order at
each of 3 levels of salt
Intervention
Change in mean B.P. vs. control (systolic)
Control diet
DASH diet
9g/d salt
Control level
- 6 mmHg
6g/d salt
- 2 mmHg
- 7 mmHg
3g/d salt
- 7 mmHg
- 9 mmHg
-7 (NT)
-11(HT)
NEJM 2001; 344:3-10
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Effects of sodium reduction on
BP over time
DASH Data:
Obarzanek, E et al. Hypertension 2003; 42:459-467
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Sodium Reduction for the Treatment of
Hypertension
Sodium substitution: a low-cost strategy for blood pressure
control among rural Chinese:
A randomized, controlled trial
• RCT of 12 months; n = 608
• Sodium Substitute (65% NaCl, 25% KCl, 10% MgSO4)
compared to normal salt (100% NaCl)
• Mean age = 60; 56% ♀; Mean BP = 159/93
• Mean SBP drop = 3.7 mm Hg (p  0.001)
• No difference in DBP
J Hypertension 2007, 25 (10)
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Sodium Reduction for the Treatment of
Hypertension
No difference in groups for food taste (saltiness)
J Hypertension 2007, 25 (10)
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What is happening in Canada
Hypertension Canada
 Developed the policy statement on dietary sodium for
Canadians
Hypertension Canada –
Canadian Hypertension Education Program
Sodium Committee
 Develops materials to support public education
 Develops materials to support health care
professional education
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What is happening in Canada
Sodium Strategic Planning Committee
– Canadian Society of Nephrology
– Dietitians of Canada
– Canadian Stroke Network
– Blood Pressure Canada
– Canadian Hypertension Society
– Heart and Stroke Foundation of Canada
– Canadian Council of Cardiovascular Nurses
– Canadian Cardiovascular Society
(Observer Public Health Agency of Canada)
 Assisted BPC in Policy Statement development re the need to
reduce dietary sodium
 Guidance for Strategy and Tactics to reduce dietary sodium
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What is happening in Canada
• Canadian Stroke Network
– “Salt Lick” award for very high sodium foods
– Sodium 101 website for Canadian information on dietary
sodium www.sodium101.ca
– Media releases on issues relating to dietary sodium of
interest to Canadians
• Heart and Stroke Foundation of Canada
– Health Check program with increasingly strict criteria of
sodium content of food.
– Media releases on issues relating to dietary sodium of
interest to Canadians
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Canada takes action
In the news:
Heath Minister Tony Clement says sodium is a bigger health threat
than artery-plugging trans fats. “It’s almost become a silent invader
of our food supply, and only now are we seeing the consequences of
it.” CanWest News Service – Oct. 26, 2007.
• Multi-stakeholder Working Group formed by Heath Canada to
oversee a reduction in dietary sodium
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•World Health Organization
•United Kingdom and most European Governments
•The Institute of Medicine
•The American Heart Association
•The American Public Health Association
•Blood Pressure Canada (BPC)
Many organizations
have concluded that
high dietary sodium
increases blood
pressure and is a
health risk
•Canadian Association of Cardiac Rehabilitation (CACR)
•Canadian Cardiovascular Society (CCS)
•Canadian Council of Cardiovascular Nurses (CCCN)
•Canadian Diabetes Association (CDA)
•Canadian Heart Failure Network (CHFN)
•Canadian Hypertension Society (CHS)
•Canadian Medical Association (CMA)
•Canadian Nurse Association (CNA)
•Canadian Pharmacists Association (CPA)
•Canadian Public Health Association (CPHA)
•Canadian Society of Internal Medicine (CSIM)
•Canadian Stroke Network (CSN)
•College of Family Physicians of Canada (CFPC)
•Dietitians of Canada (DC)
•Heart and Stroke Foundation of Canada (HSFC)
•The Kidney Foundation of Canada
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What is happening in Canada
Food Sector (via Food and Consumer Products of Canada)
– Agreed to collaboration with the health sector and
government
– With Blood Pressure Canada requested Heath
Canada involvement and oversight of the effort to
reduce dietary sodium
– More food choices low in sodium
– More advertising of low sodium foods
– Low – no sodium seasoning alternatives
– Leadership from some companies (e.g.
Campbell's Soup)
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What is happening in Canada
Processed food and beverage products sector
Food and Consumer Products of Canada (FCPC) and
BPC worked with Health Canada
To establish the multi-stakeholder Working Group
on Sodium Reduction (WG)
Mandate of the WG is:
To develop and oversee implementation of a strategy to
lower sodium content in the diets of Canadians to within
the range recommended in the IOM Dietary Reference
Intakes (DRI) Report
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What is happening in Canada
Along with FCPC six other food industry trade associations
are involved in the WG:
–
–
–
–
–
–
Baking Association of Canada
Dairy Processors of Canada
Canadian Council Grocery Distributors
Canadian Meat Council
Food Processors of Canada
Canadian Restaurant & Foodservice Association
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What is happening in Canada
Federal Government

Commissioned revised Dietary Reference Intake on sodium
(2004)

Canadian Community Health Survey (nutrition) 2004,
Prioritized sodium analysis (Health Reports 2007;18:47-52)

Importance of dietary sodium Hon S Fletcher at World
Hypertension Day May 2007

Intersectoral Work group to oversee the lowering of dietary
sodium Oct 2007

Public Health Agency of Canada Grant to develop educational
material, May 2008

Public Health Agency of Canada indirect support for health sector
(commissioning reports and assisting with meeting logistics) 2006
to date
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What is happening in Canada
Provincial Governments

Several provincial governments are examining policies to
limit high sodium foods within provincial jurisdiction (e.g.
schools)
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What is happening in Canada
Media
Strong interest in media releases from the Canadian Stroke
Network, Heart and Stroke Foundation of Canada, World
Action on Salt and Health
• Initiation of World Action on Salt and Health
• Salt intake and blood pressure in children
• Blood Pressure Canada Sodium policy
• Statistics Canada release of sodium consumption by Canadians
• Effects of high dietary sodium on hypertension in Canada
• Effects of high dietary sodium on cardiovascular disease in Canada
• International comparison on the vastly different sodium content of the
same foods in different countries- For several products Canada had
the highest amount of sodium added to their food.
• Canadian Stroke Network Salt Lick Award
• Government of Canada announcement of Intersectoral Work Group
to lower dietary sodium
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Reducing Canadians’
sodium intake
• Most dramatic impact will be to reduce
hidden sodium in manufactured foods
• Reduction can be achieved by:
– Gradual reduction of sodium by food
manufacturers and restaurateurs
– A public campaign on health benefits of sodium
reduction
– Raising consumer attention to sodium levels on
food labels
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Anticipated Outcome
• Increased consumer awareness of the health
dangers of high dietary sodium
• Increased consumer demand for lower sodium
foods
• Increased development of lower sodium foods by
the food sector
• Increased monitoring of dietary sodium as a
health parameter by the government
• Gradual reduction in dietary sodium such that
most Canadians are below the upper limited
(2020)
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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
1.
2.
3.
4.
5.
Sodium chloride, Dietary – adverse effects
Hypertension – prevention and control
Iodine – deficiency
Nutrition policy
National health programs – organization and administration
I.
II.
World Health Organization
WHO Technical Meeting on Reducing Salt Intake
in Populations (2006: Paris, France)
Title
III.
ISBN 978 92 4 159537 7
(NLM classification: QU 145)
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Resources
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