As the salt wars heat up around the world, those campaigning for a healthier food supply may find some useful lessons in previous public health campaigns, according to public health policy consultant Margo Saunders. She writes:
“First it was smoking, then it was passive smoking, then it was junk food advertising, then it was trans-fats, and now it’s salt – no, not the latest campaigns of Mayor Bloomberg, but public health initiatives that attract eerily similar anti-public health arguments from vested economic interests..
Salt, it seems, is the latest battleground, with the (US) Salt Institute on one side and just about the entire health and medical community on the other. The latest salvos were fired in two of the most august medical journals, the New England Journal of Medicine (NEJM) and Journal of the American Medical Association (JAMA).
In an article published online in the NEJM on 20 January 2010, Dr Kirsten Bibbins-Domingo and colleagues from the University of California, San Francisco, suggest that reducing salt in the US diet by 1g – 3g (1200mg of sodium) a day would have significant public health benefits. Using the Coronary Heart Disease Policy Model, they estimate that a reduction at the upper end of this scale would save close to 100 000 lives a year, save up to 392 000 quality-adjusted life-years and up to US$24 billion in healthcare costs annually.
The authors’ findings support a population-wide reduction in salt intake: “Lowering salt in the US diet would result in small but measurable reductions in blood pressure across the entire US population, thereby reducing rates of cardiovascular disease among all adults at risk”, they write. They also note that the effects of reduced salt would be proportionately greater for certain groups who have high rates of hypertension and cardio-vascular disease.
We have seen these sorts of things before, and fairly consistently, too. Even the particular problem of salt being ‘hidden’ in processed foods has been the subject of discussion for some time, and articles with titles such as ‘A case for reducing salt in processed foods’ have been appearing for at least the past 20 years.
What sent the pro-salt forces scurrying, however, was the conclusion by Bibbins-Domingo and colleagues that the findings indicate an ‘urgent call to action…to achieve these readily attainable cardiovascular benefits.’
The authors’ claims are supported by an even more forthright accompanying editorial by Drs Lawrence J Appel and Cheryl A M Anderson of Johns HopkinsUniversity, Baltimore. Appel and Anderson stress that the findings compare favourably to the results of other public health interventions and should encourage action to implement a public health approach to salt reduction in the United States, which, they say, lags behind many other countries when it comes to achieving meaningful reductions in dietary salt.
Appel and Anderson then make a point that will ring bells for patient public health advocates everywhere: they note that we have tried 40 years of consumer ‘education’ to try to get people to change their behaviour and reduce salt intake, only to find that consumption has increased or, at best, remain unchanged.
Anderson told heartwire news that, ‘People are not aware of how much salt they consume, and they are struggling to meet the recommendations,’ with much of the problem due to the ubiquitous nature of sodium in the food supply and about 75% of dietary salt in the US diet coming from processed foods. A review of the evidence should be reflected in the US Institute of Medicine’s commissioned report, ‘Population-based strategies for reducing salt intake,’ which is due to be released within the next few months.
The salt has hit the fan with a timely spray in JAMA from Dr Michael Alderman (Albert Einstein College of Medicine, New York), whom heartwire describes as ‘a well-known critic of policies to reduce salt intake at the population level’ and who acknowledges that he has, since 1996, been a member of the Diet and Cardiovascular Risk Advisory Committee of the Salt Institute.
The similarities in his line of argument are remarkably similar to those of another late, lamented industry Institute — the Tobacco Institute. In objections that could have been scripted by the tobacco industry, Alderman attempts to pick holes in the mounting research which supports reductions in dietary sodium. Alderman is not shy about stating his point of view: ‘Rarely, smoking excepted, do observational studies by repeated, robust, and consistently positive findings justify a public health recommendation.’
He then goes on to explain that, when it comes to observational cohort studies on sodium consumption and clinical outcomes, ‘the results have been conflicting’, and what we really need is are randomized clinical trials – ‘rigorous, large-scale, population-based randomized clinical trials’. Given the current evidence, says Alderman, this approach would be the ‘cautious’ and ‘prudent’ way to proceed. Moves to implement universal sodium reduction, on the other hand, constitute the ‘rash route’.
There are certainly echoes here of the arguments mounted by the tobacco industry about passive smoking and why it smoke-free enclosed public places and workplaces should not be implemented. We also heard the similar arguments from advertisers and the broadcast industry in their (so far successful) attempt to head off restrictions on junk food advertising to children.
In the meantime, important contributions are appearing in journals such as the American Journal of Clinical Nutrition, whose recent articles about the salt content of Australian foods make educational, but not entirely happy, reading. We now have brand-specific sodium content data for 7221 Australian food products.
In the months and years to come, this will facilitate monitoring; in the short-term, it reveals that much of today’s food contains more salt that we probably imagined. More than 70 percent of processed meats, cheeses, and sauces have ‘unacceptably high’ salt levels, averaging 1.3g per 100 g. What was worse, however, in terms of the proportion of the average Australian diet, was the finding that the saltiest foods were meats, bread, bakery products, dairy products and cereal. There were sizeable variations within food groups – for example, the worst frozen chips were 100 times as salty as the healthiest, and the saltiest cheese had 6 times the salt content of the healthiest.
Jacqui Webster, from the Sydney-based George Institute for International Health and the study’s lead author, says that people can live healthily on 1 – 2g of salt a day, while the recommended maximum intake is 6g a day – but most Australians consume 8 – 10g a day. Estimates by Professor Garry Jennings of Baker IDI Melbourne (probably based on the NEJM study) suggest that a dietary reduction of 3g of salt a day would prevent 3000- 6000 deaths in Australia each year.
The George Institute claims that Australia is falling behind countries including the UK, Ireland, Finland, France, Argentina and Brazil in reducing salt intakes.
According to the Institute’s AWASH (Australian Division of World Action on Salt and Health) campaign: ‘The food industry has been increasingly pouring salt into foods for decades without anyone’s knowledge or consent. With the insurmountable evidence now available about the harm this is doing to people’s health, it makes complete sense to require them to take it out.’