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: book.order@tso.co.uk

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.