High Salt Intake May Directly Increase Risk of Obesity New Study Shows

  • New analysis suggests direct link between salt intake and obesity. A 1 g/day increase in salt intake is associated with more than 25% increase in risk of obesity (both children and adults)
  • Findings are independent of energy intake or sugar-sweetened beverage consumption
  • CASH warns that an escalating obesity epidemic will cripple the NHS if the increase in diet related issues are not stopped immediately
  • Government urged to act now by applying pressure on the food industry to achieve a 30% reduction in population salt intake

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Summary of paper
A study published today in the print issue of Hypertension (02.09.15); ‘High salt intake: independent risk factor for obesity?’ [REF 1], has shown high salt intake can potentially increase risk of obesity in both adults and children.

In the first study of its kind, researchers suggest there may be a direct link between salt intake and obesity, independent of total energy intake or sugar sweetened beverage consumption (SSB). This has been highlighted in a nationally representative sample of the UK population, with a 1g/day increase in salt intake being associated with an increased risk of being overweight or obese by 28% in children and 26% in adults.

Data obtained from a total of 458 children and 785 adults taking part in the UK National Diet and Nutrition Survey’s (NDNS) rolling programme was used to assess energy intake and salt consumption [REF 2]. Results showed a consistent significant association between salt intake and BMI, waist circumference and body fat mass – independent of total energy intake and sugar-sweetened beverage consumption.

It is well established that a high salt diet is the major cause of raised blood pressure and, if left untreated, can lead to cardiovascular diseases and subsequent death [REF 3]. Recent studies have also associated a high salt diet to increased risk of obesity, primarily through its effect on thirst, leading to increased sugar sweetened beverage consumption (SSB) [REF 4], but also potentially as a result of excessive consumption of processed foods that are high in calories and salt. This new study highlights even further, the link between salt and obesity.

Reasons for these new findings are still unclear but it is thought to be related to changes in body fat metabolism [REF 5]. Further research is warranted in this area. A reduction in salt intake could help reduce obesity not only through its effect on reducing sugar-sweetened beverage consumption but may also have a direct effect on lowering obesity risk.

Professor Graham MacGregor, Professor of Cardiovascular Medicine at Queen Mary University of London and Chairman of Consensus Action on Salt & Health says: “The food we eat is now the biggest cause of ill health through its high salt, fat and sugar content added by the food industry. High blood pressure and obesity both lead to the development of cardiovascular disease, stroke, heart attacks and heart failure, which are the commonest causes of death and disability in the UK.

“Obesity also predisposes to type 2 diabetes, which further increases the risks of cardiovascular disease and can lead to severe complications. Such an epidemic will cripple the NHS if the increase in these diet related issues are not stopped immediately. The government and the food industry now need to take much stronger action. Unfortunately the previous government handed power back to the food industry with the Responsibility Deal which has completely failed to tackle these issues in the way that it needs to be.”

Current guidelines suggest we should be eating no more than 6g salt a day [REF 6] but the latest statistics show we are eating far more than we require (8.1g/day) [REF 7]. Collaborative efforts between the government and food industry however have led to progressive reductions in salt intake, resulting in a reduction in stroke and heart disease events and deaths [REF 8] but further reductions need to be made.  

Sonia Pombo, Campaign Manager for CASH, adds “This paper highlights yet another important reason to cut back on your salt intake. The food industry was working hard to reduce levels of salt levels before the Responsibility Deal and as a result average salt intakes were going down. We now need a much more robust mechanism to continue to reduce salt and to tackle the huge amounts of sugar in foods and soft drinks as well as reduce saturated fat. The responsibility lies predominantly with the food industry, where most of our salt intake comes from, but people can also make a difference to their health by reading the labels and opting for foods lower in salt, saturated fat and sugars.”

Victoria Taylor, Senior Dietitian at the British Heart Foundation, said: “It’s well established that we should be reducing the amount of salt we eat to help avoid high blood pressure, a risk factor for cardiovascular disease and the link between salt intake and obesity identified in this research could be another reason for us to do this. But more research is needed to understand what might be the reason for this link. Although the amount of salt we are eating has reduced in recent years, as a result of reformulation of manufactured foods, we are still exceeding recommended maximums.

“Most of the salt we eat is already in the foods we buy, which is why checking nutritional information on packs to make sure we are making the healthiest choice is important to help limit the amount of salt we are eating.”


Notes to Editor
National PR - David Clarke:  david@rock-pr.com M: 07773 225516
Website www.actiononsalt.org.uk

REF 1 – Ma Y, He FJ, MacGregor GA. High Salt Intake: Independent Risk Factor for Obesity? Hypertension 2015;66:00-00

REF 2 – Data was used from the National Diet and Nutrition Survey (NDNS) rolling program years 1-4 (2008/9-2011/12). The NDNS programme was a rolling cross-sectional study aiming to assess nutritional status of the general UK population. In total, 1982 children and 2174 adults participated in the NDNS core survey. Among them, 458 children (aged ≥4 years) and 785 adults had valid weight and height measurement as well as complete 24-hour urine collection, and were therefore included in our analysis.

REF 3 – He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ. 2013;346:f1325

REF 4 - A number of studies have shown an association between high salt intake and increased thirst, therefore increasing sugar-sweetened soft drink consumption:
He FJ, Markandu ND, Sagnella GA, MacGregor GA. Effect of salt intake on renal excretion of water in humans. Hypertension 2001;38:317-320
He FJ, Marrerro NM, MacGregor GA. Salt intake is related to soft drink consumption in children and adolescents: a link to obesity? Hypertension 2008;51:629-634
Grimes CA, Riddell LJ, Campbell KJ, Nowson CA. Dietary salt intake, sugar-sweetened beverage consumption, and obesity risk. Pediatrics 2013;131:14-21

REF 5 – Papers to support one possible mechanism linking salt to obesity:
• Zhu H, Pollock NK, Kotak I, Gutin B, Wang X, Bhagatwala J, Parikh S, Harshfield GA, Dong Y. Dietary sodium, adiposity and inflammation in healthy adolescents. Pediatrics 2014;133:e635-e642.
• Libuda L, Kersting M, Alexy U. Consumption of dietary salt measured by urinary sodium excretion and its association with body weight status in healthy children and adolescents. Public Health Nutr. 2012;15;433-441.
• Larsen SC, Angquist L, Sorensen TI, Heitmann BL. 24h urinary sodium excretion and subsequent change in weight, waist circumference and body composition. PLoS One. 2013;8:e69689.

REF 6 – Report by the Scientific Advisory Committee on Nutrition (SACN) on Salt and Health suggests we should be eating no more than 6g/day for adults, and even less for children.

REF 7 – Figures from the latest NDNS assessment of dietary sodium levels among adults, using accurate measurement via urinary sodium output suggests adults are eating on average 8.1g/day of salt. Salt reduction is already known to be the most cost-effective public health intervention, with a predicted £1.5bn health care saving costs in the UK alone. However UK salt intake remains high at 8.1g/day, and is way above the 6g/day target. This study highlights the need to redouble our efforts in the UK, in particular to get the food industry to act faster and more aggressively to save the maximum number of people from suffering and dying from cardiovascular disease and obesity related diseases.

REF 8 – He FJ, Pombo-Rodrigues S, MacGregor GA. Salt reduction in England from 2003 to 2011: its relationship to blood pressure, stroke and ischaemic heart disease mortality. BMJ Open2014;4;e004549.