Scientists prove that salty diet costs lives.
Eating less salt reduces the chances of suffering a heart
attack or stroke, the first long-term study of salt’s impact on health
confirms today. The findings, from a 15-year study, offer the clearest
evidence yet that cutting salt consumption saves lives by reducing the
risks of cardiovascular disease. People who ate less salty food were found
to have a 25 per cent lower risk of cardiac arrest or stroke, and a 20 per
cent lower risk of premature death. The results, published in the
British Medical Journal, underline the need for population-wide salt
reductions in the diet, the scientists conclude.
Despite campaigns to reduce salt intake, such as that run
by the Food Standards Agency (FSA), actual evidence of any benefit has
been limited. This has enabled the salt industry to contest vigorously the
value of such campaigns.
Both sides accept that cutting salt consumption reduces
blood pressure, although not very dramatically. This ought to translate
over the longer term into reductions in strokes and heart attacks, but no
studies have been able to show this convincingly until now.
The new findings are the result of work by a US team led by
Nancy Cook, of Harvard Medical School, which has followed up two trials
originally conducted in the late 1980s and early 1990s. Both were designed
to persuade people to cut their salt intake and to measure how far their
blood pressure fell.
By pursuing these trials, Dr Cook’s team has shown that
those who reduced their salt intake did have a lower risk of heart disease
and stroke. “Our study provides unique evidence that sodium reduction
might prevent cardiovascular disease and should dispel any residual
concern that sodium reduction might be harmful,” it concludes.
The interventions had reduced sodium intake by about 25-35 per cent —
roughly the same as is planned by the FSA, which is seeking to reduce
daily intake in Britain from an average of 9.5g to 6g ( /3 oz to /5 oz) a
Ellen Mason, cardiac nurse at the British Heart Foundation,
said: “Salt intake amongst many adults and children in Britain is way too
high. Many people could lower the level of salt in their diet by reducing
the amount of processed food they eat. Also, by simply checking the labels
and switching to a lower salt option, you'll be doing your heart a favour.”
But the Salt Manufacturers’ Association questioned the
quality and conclusions of the study. “The research only relates to
subjects who already have high blood pressure. Most people have
acknowledged for some time that such individuals may be advised to
restrict their salt intake with their GP’s advice. “What the evidence does not prove is that salt reduction
will have any significant health benefits for the majority of us.”
The original studies — called the trials of hypertension
prevention (TOHP 1 and 2) — used counselling and advice to persuade
participants to reduce intake. In the first trial, 327 healthy men and
women aged 30-54 who took part in the intervention were compared with 417
controls who did not.
Measurements of sodium in urine showed that a reduction of
roughly one third in salt intake had been achieved in the 327 who took
part— but blood pressure was found to fall only slightly.
The authors of the original study had no idea if this
reduction would be sustained, but estimated that if it were it might
reduce stroke deaths by 6 per cent, heart disease deaths by 4 per cent,
and deaths from all causes by 3 per cent. However, the follow-up has shown
much more marked health benefits.
The actual numbers of heart attacks and strokes are small —
76 heart attacks, 19 strokes and 23 heart deaths without previous warning
— in both TOPH 1 and 2. So it remains possible that chance, or incomplete
follow-up, have distorted the findings. Graham MacGregor, a professor at St George’s University of
London, said the size of the benefit was not surprising. “When there was a
campaign in Finland to cut salt there was a very large reduction in stroke
and heart attacks.”
Exactly how salt increases blood pressure is still in
dispute. The simplest explanation is that when salt intake is too high,
the kidneys cannot pass it all into the urine and some ends up in the
bloodstream. This then draws more water into the blood, increasing volume
and pressure. But not everybody is equally sensitive to salt, and so not
everybody will benefit equally from reducing intake.
The max recommended daily salt intake is . . .
0-6 months 1g
7-12 months 1g
1-3 yrs 2g
4-6 yrs 3g
7-10 yrs 5g
11-14 yrs 6g
. . . but some foods come close to these levels
– Campbell’s 99 per cent fat free Chicken Soup 1.9g per
–– Sainsbury’s Crumpets 2g salt per 100g
–– Dairylea Dunkers Twists 2.3g salt per 100g
–– Tesco Finest Tomato and Mascarpone Sauce 2.3g salt per
–– Sainsbury’s Oat & Bran Flakes 2.4g salt per 100g
–– Walker’s Oven Roasted Chicken and Thyme Flavour Crisps
3.6g per 100g
–– Quaker Salt and Vinegar Snack-a-Jacks 5.1g salt per 100g
Source: Food Standards Agency
Shared by Espie DeCastro
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