1
ADDITIONAL SLIDES
Excess Dietary Sodium: Impact on Hypertension and Health Outcomes
Updated 2011
2
The physiology of sodium-mediated hypertension: a primer
3
Animal studies suggest:
Van Vliet et al, 2006
• 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.
4
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.
5
Renal mechanisms forsodium-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
6
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”).
7
• Intrauterine growth retardation (IUGR)• Low nephron mass• Renal disease
Inflammation, injury, etc• Genetic abnormalities• Exogenous agents (e.g. DOCA)• Ageing sodium excretion
Factors that lead to sodium-sensitivity of blood pressure
8
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!
9
Average “hidden" sodium Intake by provinces
10
+
Sodium usual intake distribution for men and women
AI=1500
UL=2300
Men 19-30y
Women 19-30y
Men 31-50y
Women 31-50y
0
0.0001
0.0002
0.0003
0.0004
0.0005
0.0006
0.0007
0.0008
0 1000 2000 3000 4000 5000 6000 7000 8000Sodium (mg/d)
Re
lativ
e p
rob
ab
ility
de
nsi
ty
• Results are based on the Canadian Community
Health Survey - Cycle 2.2 on Nutrition, Statistics
Canada, 2004. • Usual intake distributions were estimated using the
Software for Intake Distribution Estimation (SIDE),
Iowa State University, 1986
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 70.8CCHS 2.2 Statistics Canada, 2004
11
The sodium intake of most Canadians adults exceeds the UL
Health Reports, Vol. 18, No 2, May 2007
0
20
40
60
80
100
19 to 30 31 to 50 51 to 70 71 orolder
Male
Female
Upper Limit 2300 2300 2300 2300
% above UL
12
Hidden sodium intake and salt added at the table
Never Rarely Occasionally Very often
Add salt to food at table
2,927
3,074
3,182
3,396
*
*
“Hid
den
“ so
diu
m i
nta
ke
* Average “ hidden” sodium intake
Health Reports, Vol. 18, No 2, May 2007
13
Salt use by hypertensive adults
Add salt to food at table
Yes
No
Canadians age >30 years diagnosed with high blood pressure
Never Rarely Occasionally Very often
36
30 3032
19
25
1316
*
*
*
% o
f re
spon
dent
s40
30
20
10
Health Reports, Vol. 18, No 2, May 2007
14
Sodium and Blood Pressure: Intersalt
BMJ. 1988 July 30; 297(6644): 319–328
15
Relationship between sodium intake and fluid consumption in children/adolescents
R=0.40p<0.001
He et al Salt Intake, Soft Drinks, and Obesity in Children, Hypertension. 2008;51:629-634
16
Sodium in our Diet
Natural~15%
Discretionary~15%
Manufactured food processing~70%
Adequate Intake*1,500 mg/d (3.8 g salt)
Tolerable Upper Intake*2,300 mg/d (5.8 g salt)
Reference Standard**2,400 mg/d (6.1 g salt)
3,000 – 4,000 mg/d (8-10 g salt)
*Health Canada. Dietary Ref. Intake Reports
**2003 labeling legislation
17
The sodium intake of most Canadian children/youth exceeds the UL
Health Reports, Vol. 18, No 2, May 2007
0
20
40
60
80
100
1 to 3 4 to 8 9 to 13 14 to 18
Male
Female
Upper Limit 1500mg 1900 2200 2200
% above UL
18
Av. Sodium Intake* (mg/day)
of Canadian Children and Youth
*Does not include sodium added at the table or during home cooking
Ref: Canadian Community Health Survey, Nutrition Survey
0500
10001500200025003000350040004500
1-3 yr 4-8 yr 9-13 yr 14-18yr
Male Female M&F
19
The sodium intake of most Canadian children/youth exceeds the UL
Health Reports, Vol. 18, No 2, May 2007
1500mg 1900 2200 2300 Upper Level
% above UL
0
20
40
60
80
100
1-3 yr 4-8 yr 9- 13yr 14-18 yr
MaleFemale
M & F
20
Sodium restriction reduces BPin 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
21
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
22
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
23
Sodium reduction interventions are as effective as smoking cessation interventions
in saving lives
0
1
2
3
4
5
6
7
8
Combinedpackage of
intervention
Interventionto reducesodiumintake
Interventionto control
tobacco use
Men
Women
De
ath
s (m
illio
ns
)
13.8
8.5
5.5
The Lancet, Volume 370, Issue 9604, 2044-2053, December 2007
24
Deaths averted by implementation of tobacco and sodium interventions by type of diseases
0
10
20
30
40
50
60
70
80
Cardiovasculardiseases
Respiratorydiseases
Cancer
De
ath
s (%
)
75,6%
15,4%8,7%
The Lancet, Volume 370, Issue 9604, 2044-2053, December 2007
25
Treatment Study: DASH Sodium
• 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
NEJM 2001; 344:3-10
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
Randomized 412 adults (mixed B.P. status, racial groups, sexes) to:
-7 (NT)-
11(HT)
26
Effects of sodium reduction on BP over time
Obarzanek, E et al. Hypertension 2003; 42:459-467
DASH Data:
27
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
Sodium Reduction for the Treatment of Hypertension
J Hypertension 2007, 25 (10)
28
Sodium Reduction for the Treatment of Hypertension
No difference in groups for food taste (saltiness)
J Hypertension 2007, 25 (10)
29
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
30
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
31
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
32
33
Canada takes action
• Multi-stakeholder Working Group formed by Heath Canada to oversee a reduction in dietary sodium
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.
34
Many organizations have concluded that high dietary sodium increases blood pressure and is a health risk
•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)
•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
35
What is happening in CanadaFood 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)
36
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
37
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
38
What is happening in CanadaFederal 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
39
What is happening in Canada
Provincial Governments
Several provincial governments are examining policies to limit high sodium foods within provincial jurisdiction (e.g. schools)
40
What is happening in CanadaMedia
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
41
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
42
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)
43
Resources
44
Resources
WHO Forum on Reducing Salt Intake in Populations (2006:Paris,France)
Reducing salt intake in populations: report of a WHO forumand technical meeting, 5-7 October 2006, Paris, France
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)
45
Resources
Onlinewww.tso.co.uk/bookshop
Mail, Telephone, Fax & E-mailTSOPO Box 29, Norwick NR3 1GN
Telephone orders/General enquiries: 0870 600 5522Order through the parliamentary HotlineLo-call 0845 7 023474
Fax orders: 0870 600 5533
E-mail: [email protected]
Textphone 0870 240 3701
46
For your patients – ask them to sign up at www.myBPSite.ca for free access to the latest Information & resources on HBP
For health care professionals – sign up at www.htnupdate.ca for automatic updates and on current hypertension educational resources.
Top Related