Salt intake in China among highest in the world for the past four decades

12 July 2019

Salt intake in China is confirmed to be among the highest in the world, with adults over the past four decades consistently consuming on average above 10g of salt a day, which is more than twice the recommended limit, according to new research led by Queen Mary University of London.

The systematic review and meta-analysis, funded by the National Institute for Health Research and published in the Journal of the American Heart Association, also found that Chinese children aged 3-6 are eating the maximum amount of salt recommended by the World Health Organization for adults (5g a day) while older children eat almost 9g/day.

Excess salt intake raises blood pressure, a major cause of strokes and heart disease, which accounts for approximately 40 per cent of deaths in the Chinese population.

The team reviewed all data ever published on salt intake in China (which involved about 900 children and 26,000 adults across the country) and found that salt intake has been consistently high over the past four decades, with a North-South divide.

While salt intake in northern China is among the highest in the world (11.2g a day) it has been declining since the 1980s when it was 12.8g a day, and most markedly since the 2000s. This could be the result of both governmental efforts in salt awareness education and the lessened reliance on pickled food – owing to a greater year-round availability of vegetables.

However, this trend of decrease was not seen in southern China, which has vastly increased from 8.8g a day in the 1980s to 10.2g a day in the 2010s. This could be due to governmental efforts being mitigated by the growing consumption of processed foods and out-of-home meals. These latest results contradict those of previous studies based on less robust data which reported declines in salt intake across the country.

Potassium, which is naturally found in fruits and vegetables, and is in potassium salt, has the opposite effect of sodium (salt) on blood pressure: while sodium increases blood pressure, potassium lowers it.

The researchers reviewed potassium intake and found that in contrast to salt intake, it has been consistently low throughout China for the past four decades, with individuals of all age groups consuming less than half the recommended minimum intakes.

Lead author Monique Tan from Queen Mary University of London said: "Urgent action is needed in China to speed up salt reduction and increase potassium intake. High blood pressure in childhood tracks into adulthood, leading to cardiovascular disease. If you eat more salt whilst you are young, you are more likely to eat more salt as an adult, and to have higher blood pressure. These incredibly high salt, and low potassium, figures are deeply concerning for the future health of the Chinese population.”

Feng J He, Professor of Global Health Research at Queen Mary University of London and Deputy Director of Action on Salt China, added: "Salt intake in northern China declined, but is still over double the maximum intake recommended by the WHO, while salt intake actually increased in southern China. Most of the salt consumed in China comes from the salt added by the consumers themselves while cooking. However, there is now a rapid increase in the consumption of processed foods and of food from street markets, restaurants, and fast food chains, and this must be addressed before the hard-won declines are offset.”

Graham MacGregor, Professor of Cardiovascular Medicine at Queen Mary University of London and Director of Action on Salt China said: "A coherent, workable, and nationwide strategy is urgently needed in China. As much as a fifth of the world’s population lives in China. Achieving salt reduction together with increasing potassium intake across the country would result in an enormous benefit for global health.”

The trends found in this latest study partially contradict those of earlier studies which found large declines of salt intake across the whole of China. The researchers say these latest results are far more robust than the previous estimates which have relied on surveys of people’s dietary habits. The team instead determined salt intake exclusively with the use of data from urine samples taken over a 24 hour period.

Salt intake assessed by dietary methods is unreliable because most of the salt in the Chinese diet comes from the salt added during home cooking or in sauces, which is highly variable and difficult to quantify. Furthermore, processed and out-of-home foods are increasingly consumed but their salt content tends to be inaccurately reported in food composition tables.

ENDS

 

For more information, please contact:

Joel Winston

Communications Manager (School of Medicine and Dentistry)

Queen Mary University of London

1. winston@qmul.ac.uk
2. Research paper: Tan M, He FJ, Wang C, et al. Twenty-Four-Hour Urinary Sodium and Potassium Excretion in China: A Systematic Review and Meta-Analysis. J Am Heart Assoc. Epub ahead of print 2019. DOI: 10.1161/JAHA.119.012923

Tel: +44 (0)20 7882 7943 / +44 (0)7968 267 064

 

Terry Lu

Communication Manager

The George Institute for Global Health (China)

tlu@georgeinstitute.org.cn

Tel: 86 10 8280 0577-212

 

Notes to editor

Comparison with other countries

 

Only countries where 24-hour urinary sodium excretion of a nationally representative sample has been reported.

 

Country	Mean salt intake in adults (g/d)*	Reference
Australia	9.0	Santos JA, Webster J, Land M-A, et al. Dietary salt intake in the Australian population. Public Health Nutr 2017; 20: 1887–1894
Barbados	6.6	Harris RM, Rose AMC, Hambleton IR, et al. Sodium and potassium excretion in an adult Caribbean population of African descent with a high burden of cardiovascular disease. BMC Public Health 2018; 18: 998
Benin	9.9	Mizéhoun-Adissoda C, Houinato D, Houehanou C, et al. Dietary sodium and potassium intakes: Data from urban and rural areas. Nutrition 2017; 33: 35–41
Canada	8.3	Mente A, Dagenais G, Wielgosz A, et al. Assessment of Dietary Sodium and Potassium in Canadians Using 24-Hour Urinary Collection. Can J Cardiol 2016; 32: 319–326
England	8.1	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 Open 2014; 4: e004549
India	9.1	Johnson C, Mohan S, Rogers K, et al. Mean Dietary Salt Intake in Urban and Rural Areas in India: A Population Survey of 1395 Persons. J Am Heart Assoc; 6. Epub ahead of print 06 2017. DOI: 10.1161/JAHA.116.004547
Italy	9.7	Donfrancesco C, Ippolito R, Lo Noce C, et al. Excess dietary sodium and inadequate potassium intake in Italy: Results of the MINISAL study. Nutr Metab Cardiovasc Dis 2013; 23: 850–856
Montenegro	10.7	D’Elia L, Brajović M, Klisic A, et al. Sodium and Potassium Intake, Knowledge Attitudes and Behaviour Towards Salt Consumption Amongst Adults in Podgorica, Montenegro. Nutrients 2019; 11: 160.
New Zealand	8.5	McLean R, Edmonds J, Williams S, et al. Balancing Sodium and Potassium: Estimates of Intake in a New Zealand Adult Population Sample. Nutrients 2015; 7: 8930–8938
Portugal	10.5	Polonia J, Martins L, Pinto F, et al. Prevalence, awareness, treatment and control of hypertension and salt intake in Portugal: changes over a decade. The PHYSA study. J Hypertens 2014; 32: 1211–1221
Samoa	7.3	Trieu K, Ieremia M, Santos J, et al. Effects of a nationwide strategy to reduce salt intake in Samoa. J Hypertens 2018; 36: 188–198
United States	9.0	Cogswell ME, Loria CM, Terry AL, et al. Estimated 24-Hour Urinary Sodium and Potassium Excretion in US Adults. JAMA 2018; 319: 1209–1220

 

*Salt intake calculated from the 24-h urinary sodium excretion with a conversion factor of 2.5 (1 g of sodium = 2.5 g of salt), without correcting for non-urinary losses of sodium.

 

 

Regional breakdowns of salt intake in China

 

Latest data only (i.e. collected in the 2010s).

Administrative region	Salt intake equivalent (g/d)*
Hong Kong Special Administrative Region	7.6
Guangdong Province	8.5
Jiangxi Province	8.9
Tianjin City	9.7
Shaanxi Province	10.1
Beijing	10.3
Jiangsu Province	10.6
Shanghai	10.9
Heilongjiang Province	10.9
Hunan Province	10.9
Gansu Province	10.9
Liaoning Province	11.5
Chongqing	11.5
Shanxi Province	11.5
Shandong Province	11.6
Sichuan Province	12.4
Hebei Province	12.7
Ningxia Hui Autonomous Region	14.4

*Salt intake calculated from the 24-h urinary sodium excretion with a conversion factor of 2.5 (1 g of sodium = 2.5 g of salt), without correcting for non-urinary losses of sodium.

 

Conversion values from millimoles (mmol) of sodium to grams (g) of salt

 

The figures in the journal articles are reported in millimoles, as it is the usual unit in which 24-hour sodium and potassium excretion are reported. However, this press release refers to grams of salt and grams of potassium, as these are more easily understood by the public.

 

1 mmol of sodium = 23 mg of sodium, and 1 g of sodium = 2.5 g of salt.

 

Salt intake by decade and by region, with conversion:

 

	Whole of China		Northern China		Southern China
	Sodium	Salt	Sodium	Salt	Sodium	Salt
1980s	192.84 mmol	11.1 g	222.49 mmol	12.8 g	152.51 mmol	8.8 g
1990s	191.20 mmol	11.0 g	228.97 mmol	13.2 g	150.36 mmol	8.6 g
2000s	201.07 mmol	11.6 g	242.95 mmol	14.0 g	195.99 mmol	11.3 g
2010s	181.51 mmol	10.4 g	194.53 mmol	11.2 g	178.15 mmol	10.2 g

 

About Queen Mary University of London

 

At Queen Mary University of London, we believe that a diversity of ideas helps us achieve the previously unthinkable.

 

In 1785, Sir William Blizard established England’s first medical school, The London Hospital Medical College, to improve the health of east London’s inhabitants. Together with St Bartholomew’s Medical College, founded by John Abernethy in 1843 to help those living in the City of London, these two historic institutions are the bedrock of Barts and The London School of Medicine and Dentistry.

 

Today, Barts and The London continues to uphold this commitment to pioneering medical education and research. Being firmly embedded within our east London community, and with an approach that is driven by the specific health needs of our diverse population, is what makes Barts and The London truly distinctive.

 

Our local community offer to us a window to the world, ensuring that our ground-breaking research in cancer, cardiovascular and inflammatory diseases, and population health not only dramatically improves the outcomes for patients in London, but also has a far-reaching global impact.

 

This is just one of the many ways in which Queen Mary is continuing to push the boundaries of teaching, research and clinical practice, and helping us to achieve the previously unthinkable.