British Study Links High Intake of Salt to Social Inequalities

According to a new study led by the Warwick Medical School, people from low socio-economic positions in the United Kingdom eat more salt than the well off, irrespective of where they live.

Salt farmers harvesting salt in Pak Thale, Thailand (JJ Harrison / CC BY-SA 3.0)

The research, published in the BMJ Open journal, looked at the geographical distribution of habitual dietary salt intake in the UK and its association with manual occupations and educational attainments, both indicators of socio-economic position and key determinants of health.

The scientists used the British National Diet and Nutrition Survey – a national representative sample of 2,105 men and women aged 19-64 years living in the UK. Salt intake was assessed with two independent methods: a seven-day dietary record and the ‘gold standard’ 24-h urine collections for sodium determination – direct marker of salt intake.

The results show salt intake is significantly higher in those with low educational attainment and in manual occupations, when the effects of geographical variations are stripped out – people living in Scotland had higher salt intake than those in England and Wales.

“These results are important as they explain in part why people of low socio-economic background are more likely to develop high blood pressure and to suffer disproportionately from strokes, heart attacks and renal failure,” said study senior author Prof Francesco Cappuccio of the WHO Collaborating Center.

“We have seen a reduction in salt intake in Britain from 9.5 to 8.1 g per day in the period 2004-2011, thanks to an effective policy which included awareness campaigns, food reformulation and monitoring.”

“Whilst this is an achievement to celebrate, our results suggest the presence of social inequalities in levels of salt intake that would underestimate the health risks in people who are worse off – and these are the people who need prevention most.”

Prof Cappuccio said: “the diet of disadvantaged socio-economic groups tends to be made up of low-quality, salt-dense, high-fat, high-calorie unhealthy cheap foods. Behavioral approaches to healthy eating are unlikely to bring about the changes necessary to halt the cardiovascular epidemic and would also widen inequalities.”

“Since the majority of dietary salt is added during commercial food production, widespread and continued food reformulation is necessary through both voluntary as well as regulatory means to make sure that salt reduction is achieved across all socio-economic groups,” he concluded.

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Bibliographic information: Chen Ji, Ngianga-Bakwin Kandala, Francesco P Cappuccio. Spatial variation of salt intake in Britain and association with socioeconomic status. BMJ Open 2013;3:e002246; doi: 10.1136/bmjopen-2012-002246