Research Impact


Improving the health of a nation

Reducing the burden of chronic disease in sub-Saharan Africa by influencing public health policy on salt 

High levels of salt consumption around the world are contributing to rising levels of high blood pressure, which is one of the biggest contributors to cardiovascular diseases and stroke. Population wide salt reduction strategies are considered a best-buy approach to reduce the growing burden of chronic diseases in most countries.

South Africa is the first country to mandate salt levels allowed in a wide range of commonly consumed processed foods. The policy – influenced by the research of UOW’s Associate Professor Karen Charlton – was implemented on 30 June 2016, with more stringent targets being implemented by June 2019.

Studies by A/Prof Charlton in 1990s provided evidence to the South African government towards its salt reduction policy. Modelling showed that reducing the sodium content of bread by 32 per cent, along with other proposed reductions in margarine, soups and stocks, 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.

This research, along with advocacy efforts resulted in A/Prof Charlton acquiring a grant of more than AUD$1 million over five years from Bloomberg Philanthropies Foundation, USA for a project to evaluate the effectiveness of the policy.

She is collaborating with Dr Paul Kowal from the World Health Organization, Geneva, to include a salt sub-study in the multi-country, longitudinal WHO Study on Global AGEing and Adult Health (SAGE).

During SAGE Wave 2 in 2015, 24 hour sodium excretion was analysed in over 2,400 people in South Africa and Ghana (a comparative country with no salt targets in place) to obtain baseline information, pre salt legislation, on salt intakes. These will be compared against post salt legislation values collected during SAGE Wave 3 in 2017-18.

In September 2016, A/Professor Charlton convened a High Level Salt Reduction Consultation Meeting with stakeholders, including the National Department of Health and the South African Heart and Stroke Foundation in Cape Town. Preliminary results from the SAGE study were presented, including that 53 per cent of adults aged 50 years and over, and 33 per cent of adults aged 18-49 years, were hypertensive.

Of those adults with hypertension, two out of three people in the older group, and 75 per cent of the younger group, were not aware of their condition. Only one in four people with hypertension received any blood pressure medication, with only one in every ten taking effective blood pressure medication that kept their blood pressure under control. Sixty-five percent of individuals were consuming levels of salt above the target of 5 grams per day, and 40 per cent of younger adults had very high intakes - above 9 grams per day.

The outcomes of this meeting were published as a glossy report by the WHO Collaborating Center on Population Salt Reduction and an editorial in the South African Medical Journal.

This early data firmly supports the South African government’s campaign to change the food supply to reduce salt intake, A/Prof Charlton says.

“It’s important to monitor the effectiveness of food policy, and governmental efforts to change dietary behaviour for the purpose of lowering non communicable diseases in low-to-middle income countries where health services cannot cope with the increasing burden of hypertension and its associated adverse cardiovascular outcomes.”

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Partner organisations

World Health Organization (WHO), Switzerland
CDC Foundation, with financial support provided by Bloomberg Philanthropies (USA)
WHO Collaborating Center on Salt Reduction
George Institute for Global Health
North-West University, South Africa
Department of Community Health, University of Ghana, Ghana
Heart and Stroke Foundation of South Africa

UOW participants

A/Prof. Karen Charlton