Bernie Goldie

South Africa leads the way in salt reduction following UOW research

The work of a UOW researcher, Associate Professor Karen Charlton from the School of Health Sciences, has been instrumental in placing South Africa at the forefront of public health initiatives to improve their food supply.

In a bold step taken by the South African Department of Health, legislation has been passed for mandatory salt reduction target levels in foods. South Africa is the first country globally to enforce a population-level approach to lower salt intake.

Maximum salt levels have been set for bread, margarine and spreads, savoury snacks, processed meats, soup powders and stock cubes.

It is estimated that reducing the sodium content of bread by 50%, along with other proposed reductions in margarine, soups and gravies, would decrease salt intake by 0.85 grams per day, resulting in 7,000 fewer deaths due to cardiovascular disease and 4,000 less non-fatal strokes in the country per year, saving the country 300 million Rands (~$40 million) each year in health-care costs associated with non-fatal strokes alone.

Professor Charlton said that in South Africa, ischaemic heart disease and stroke were the leading causes of death after HIV.

“Without a doubt, there is excellent, high quality evidence that salt reduction leads to clinically important blood pressure improvements, in both people with and without hypertension.

“High salt intake increases risk of stroke and cardiovascular disease, as well as gastric cancer in some populations. Importantly, salt intake in childhood contributes to the development of hypertension in later life and a preference for salt taste develops in children as young as two years if they are exposed to high-salt diets,” she said.

In a landmark study, people with hypertension from an impoverished community were provided with salt-reduced versions of commonly consumed foods, while a control group received the exact foods but of standard composition. The foods looked identical so blinding of research subjects and researchers was possible. After just eight weeks, systolic blood pressure dropped by 6.2 mmHg -- which is the magnitude of effect usually only seen with drug therapy.

“We took a very practical approach to our research -- firstly, we identified the main contributors to salt intake in the diets of South Africans, then we worked with the food industry to develop salt-reduced variants of these foods, and lastly, tested them in a community-based randomised controlled trial. It was essential that we were able to demonstrate that the approach was technologically feasible, culturally acceptable, and cost-effective,” Professor Charlton said.

Professor Krisela Steyn, Associate Director of the Chronic Diseases Initiative in Africa at the University of Cape Town and a member of the research teamwork said they were able to convince representatives from the Department of Health that this was an essential approach in South Africa where severely limited health resources were unable to cope with the increasing burden of chronic disease.

“Our hard work over the past few years to disseminate these study findings - not only in the peer-reviewed literature but also through policy briefs and the media has paid off,” Professor Steyn said.

Professor Charlton said that in Australia, there have been advances in the salt reduction arena but progress is slow.

The lobby group, Australian World Action on Salt and Health (AWASH) advocates for action from government and the food industry. Voluntary salt reduction targets have been set through a Food and Health Dialogue that brings together food industry partners and health agencies.

However, salt intakes are still high, at around 9g salt per day, more than double the recommended amount of 4g/day, Professor Charlton said.

She identified a three-pronged recipe for a successful population-level salt reduction strategy:

    • Engage the food industry – most salt is in processed foods

    • Educate consumers to be salt savvy and understand food labels - salt content information is provided as milligrams of sodium (Na), rather than grams of salt (1g Na = 2.5g salt). This needs to be simplified, and signposting provided to help time-poor shoppers, such as the Heart Foundation’s Tick or front-of-pack traffic-light labelling

    • Encourage state governments to stipulate maximum salt levels for foods served in community institutions such as schools, hospitals, leisure centres and the workplace

Meanwhile, Professor Charlton has been invited to speak about the research at a symposium being held in Sydney on 28-29 September. The symposium is taking place as part of a satellite meeting called ‘Physical Activity, Nutrition and a Pinch of Salt’ connected with Hypertension Sydney.

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  • Associate Professor Karen Charlton . . . her salt-reduction research paves the way for legislative change in South Africa