Salt The Need for Action

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SaltThe Need for Action
Prof. Graham A MacGregorSt. Georges
HospitalLondon
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Leading causes of death worldwide in 2002
Cardiovascular diseases
Infectious and parasitic diseases
Cancer
Respiratory infections
Respiratory diseases
Unintentional injuries
Perinatal conditions
Digestive diseases
Intentional injuries
Neuropsychiatric conditions
Diabetes mellitus
Genitourinary diseases
Maternal conditions
Congenital anomalies
Nutritional deficiencies
Others
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
Number of deaths (x1000)
3
Atheroma in carotid artery
Plaque
Ulcerated Plaque
Fissured Plaque with Thrombosis
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Major modifiable risk factors

• ? Blood pressure
• ? Total LDL cholesterol, ?HDL
• Smoking
• Diabetes
• Lack of fruit and vegetables
• Lack of exercise
• Male pattern obesity

Unmodifiable

• Age
• Genetics

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WHO Report
Worldwide

• About 1 billion individuals have raised BP

• Raised BP is responsible for

62 of all Strokes 49 of all Heart Disease
WHO Report 2002. www.who.int/whr/2002.
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Major Underlying Factors causing Death - Worldwide
Raised Blood Pressure
7 million
Tobacco
High cholesterol
Underweight
Unsafe sex
Low fruit vegetables intake
High BMI
Developed region
Physical inactivity
Developing region
Alcohol
Unsafe water, sani hygiene
0
1
2
3
4
5
6
7
Millions of Deaths
Ezzati et al. Lancet 20023601347-60.
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Systolic BP and Risk of Death
Heart Deaths
Stroke Deaths
16
32
8
16
8
4
Risk
Risk
2
4
1
2
120
125
135
148
168
120
125
135
148
168
Systolic Blood Pressure (mmHg)
The risk starts at systolic 115 mmHg (83 adults)
MacMahon et al. Lancet 1990335765-74
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Yanomamo Indians
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South American Indians
On Evolutionary Diet
i.e. no salt, very little fat, no refined
carbohydrate, fruits vegetables Å, but
aggressive fit, stress ÅÅ
Male adults
Average BP 96/61 mmHg
Average Cholesterol 3.1 mmol/l
No rise in either with age
No vascular disease
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What puts up population BP?

• Salt intake
• Lack of Fruit and vegetables
• Weight
• Lack of Exercise
• (Alcohol excess)

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Salt
Until 5000 yrs ago 0.1 grams of salt per day
Now 10 to 12 grams per day
Why this big increase?
Magical property of preserving food
(a)
(b)
Cleans up tainted and/or unpalatable food
Deep freeze refrigerator
Therefore now no need
But still eating 10 to 12 gram per day courtesy
of the food industry
80 (9.6 grams) of salt hidden in food
Only 15 (1.8 grams) added by consumer
Salt, diet health. 1998, Camb Uni Press
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Evidence

• Epidemiology Over 50 population studies and
  Intersalt
• Migration e.g. Kenya
• Intervention Portuguese villages. New born babies
• Genetic All defects identified so far impair the
  ability of the kidney to excrete salt
• Mechanisms Plasma Na, corrected volume expansion
• Animal All forms of hypertension are caused or
  aggravated by salt. Chimpanzees
• Treatment Trials, Meta-analysis. Dose response
• Mortality studies Finland (24h UNa)
• Outcome trials TOHP, Taiwan (mineral salt high
  K, low Na)

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? BP with age v salt intake (INTERSALT). n10,079
1.4
1.2
R 0.566 P lt0.001
1.0
0.8
Increase in SBP with Age (mmHg per yr)
0.6
0.4
0.2
0.0
0
3
6
9
12
15
Salt (grams)/day (from 24hr Una)
6 gram/day ? from 25 to 55 yrs ? SBP 9mmHg ?
Adapted Intersalt, BMJ 1988297319-32
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Double-Blind study of modest salt reduction (n19)
Randomised double-blind crossover
Usual Salt 4 wks
Reduced Salt 4 wks
168
166
164
Supine SBP (mmHg)
Mean fall 9.5 mmHg
162
P0.001
160
158
156
154
152
92
91
Supine DBP (mmHg)
90
Mean fall 5.3 mmHg
P0.004
89
88
87
86
175
150
Urinary Sodium (mmol/24h)
Mean fall 4.5 g/day of salt
P0.001
125
100
75
50
25
0
0
Lancet. 19821351-355
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DASH-Sodium Trial (All participants N412)
Salt intake (g/day)
8
6
4
Systolic BP (mmHg)
Control Diet
DASH Diet
Diastolic BP (mmHg)
Control Diet
DASH Diet
Urinary Sodium (mmol/24h)
Sacks et al. NEJM 2001 3443-10.
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Dose Response Meta-analysis (1 month or longer)
Change in Systolic BP (mmHg)
Normotensives b0.04, Plt0.001
Hypertensives b0.07, Plt0.001
Change in Urinary Sodium (mmol/24h)
\ A 6 g/day reduction in salt intake predicts a
fall in SBP of
? 7 mmHg in Hypertensives (plt0.001)
? Avg. 5 mmHg
? 4 mmHg in Normotensives (plt0.01)
J Human Hypertens 200216761
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Predicted effect on Stroke and Heart Attack
Deaths(BP fall from Meta-analysis)

• Reducing salt by 1 gram / day would reduce ?
  strokes by 5
• Reducing salt by 6 gram / day would reduce ?
  strokes by 24

? heart attacks by 3
? heart attacks by 18

• Reducing salt by 9 gram / day would reduce ?
  strokes by 34

? heart attacks by 25
Hypertension 2003421093-99
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Meta-analysis dose response
Calculated

• salt intake 6 g/d
• (10-12 to 5-6 g/d WHO recommended)

? Stroke 24
? CHD 18
He MacGregor. Hypertension 2003421093
UK
?35,000 stroke heart attack deaths prevented
/year
?150,000 stroke heart attack deaths prevented
/year
USA
Worldwide Approx. 2.5 million stroke heart
attack deaths prevented / year
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Outcome trial TOHP I, II

Salt 25-30 ? for 18-48 months N 3126
Baseline BP 127/85 mmHg Follow- up 10-15
years post trial
Cook et al. BMJ 2007
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Benefits of Reducing Population Salt Intake
Salt 4.6 g/d ?
Hypertension prevalence 30 ?
Direct cost savings (Physician visits,
medications laboratory tests) 430 million
per year in Canada ? 1 billion per year in UK
Forrester etal. J Human Hypertens 2005 19 55-60.
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Salt - Other harmful effects

• Cancer of the stomach
• (? Salt (gastric irritant) - ? H pylori)
• Stroke
• LVH
• Heart failure. Idiopathic cyclical oedema
• Kidney disease / Albuminuria
• Renal stones
• Bone demineralisation (osteoporosis)
• (? Salt - ? Urinary calcium)
• Asthma
• Menieres

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Salt Stroke
Portugal
Perry Beevers. J Hum Hypertens 1992623.
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Summary
Salt intake (10 12 g/day)

• Population BP, rise in BP with age, hypertension

• Other effects e.g. stomach cancer, stroke, LVH,
  kidney disease, osteoporosis etc

Reduce salt intake

• from 10 - 12 g/day to 5 - 6g/day

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Salt Intake

• Hidden salt
• Added salt (Cooking, Table)
• Salt

• Sauces/Spices, e.g. soya
• Dried products, e.g. salted fish

Strategy depends on major source of salt in each
country
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Strategy for Reducing Salt
Current salt intake / day
Reduction needed
Table / Cooking (15)
0.9 g
50 reduction
1.8 g
Natural (5)
0.6 g
No reduction
0.6 g
Food industry (80)
4.5 g
53 reduction
9.6 g
Total 12 g
Target 6 g
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Hidden Salt Its Commercial Value
SALT
Profit
Producers (40 by value)
Food Industry
Meat products Salt
Dependence on salty taste (Salt Addiction)
Highly Salted Processed Food (many
seawater) 80 of intake
Water Binding
Salt
Salt
Salt
Demand for very salty foods
Weight No Cost
Thirst
Profit
Soft Drinks Mineral Water
Profit
Profit
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Sea Water Comparison per 100g in UK

• Cheese Tomato Pizza 50
• Chicken Curry Ready Meal 30
• Processed Cheese 130
• Bacon 180
• Sausages 50
• Smoked Fish 170
• Sweet Pickle 160
• Lasagne 30
• Shepherds Pie 40
• Frozen Prawns 70
• Crisps 60
• Salad Cream 90
• Savoury Biscuits 60

Medium Sliced White 45 Granary
Loaf 40 Crumpets 80 Plain Scones 60 Digestive 4
0 Cream Crackers 50 Cheddar Cheese 70 Stilton
Cheese 90 Salted Butter 80 Branflakes 75 Cornfl
akes 95 Tomato Ketchup 100 Brown Sauce 90
2.5g of salt per 100g sea water. Data collected
June 2007
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Sun newspaper 05/08/2004
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Consensus Action on Salt Health (CASH)
Initial aims
?

• Change DoH policy
• Ensure FSA adopted salt reduction and labeling
• Media publicity to the public and food industry
• Persuade retailers and food companys to reduce
  salt added to food

?
?
??
Current aims

• Media publicity
• Name and shame companies not responding
• Praise companies responding
• Ensure FSA remains on target

www.actiononsalt.org.uk
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World Action on Salt Health (WASH)
260 members worldwide, 55 countries
Target ? Salt intake worldwide to 5g (WHO target)
Food industry

• Globally Monitor and highlight foods high in salt
• Implement salt reduction plan worldwide
• Clear labeling system (traffic light)

Government

• Adopt scientific evidence as in Finland, UK and
  ensure action

Public

• Public health campaign to reduce salt consumption
  at home

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Summary
? Stroke ? Heart Attacks ? Heart Failure

• ?Salt intake ?BP
• ? Salt intake biggest improvement in
  public health since clean water and drains (19th
  Century)

? Stomach Cancer Osteoporosis
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www.salt.gov.uk