Objective: Salt reduction is a public health priority because it is a leading contributor to the global burden of disease. As in Australia there is uncertainty about the current level of salt intake, we sought to estimate current levels.
Study design: Random effects meta-analysis of data from 31 published studies and one unpublished dataset that reported salt or sodium consumption by Australian adults on the basis of 24-hour urine collections or dietary questionnaires.
Data sources: MEDLINE (via Ovid) and EMBASE (to August 2016).
Data synthesis: Thirty-one published studies and one unpublished dataset (1989–2015; 16 836 individuals) were identified. The mean weighted salt consumption estimated from 24-hour urine collections was 8.70 g/day (95% CI, 8.39–9.02 g/day); after adjusting for non-urinary salt excretion, the best estimate of salt intake in Australia is 9.6 g/day. The mean weighted intake was 10.1 g/day (95% CI, 9.68–10.5 g/day) for men and 7.34 g/day (95% CI, 6.98–7.70 g/day) for women. Mean weighted consumption was 6.49 g/day (95% CI, 5.94–7.03 g/day) when measured with diet diaries, 6.76 g/day (95% CI, 5.48–8.05 g/day) when assessed with food frequency questionnaires, and 6.73 g/day (95% CI, 6.34–7.11) when assessed by dietary recall. Salt intake had not decreased between 1989 and 2015 (R2 = –0.02; P = 0.36).
Conclusion: Salt intake in Australian adults exceeds the WHO-recommended maximum of 5 g/day and does not appear to be declining. Measuring salt intake with methods based on self-reporting can substantially underestimate consumption. The data highlight the need for ongoing action to reduce salt consumption in Australia and robust monitoring of population salt intake.
- 1. Australian Institute of Health and Welfare. Cardiovascular disease: Australian facts 2011 (AIHW Cat. No. CVD 53). Canberra: AIHW, 2001.
- 2. Lozano R, Naghavi M, Foreman K, et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2095-2128.
- 3. Micha R, Penalvo JL, Cudhea F, et al. Association between dietary factors and mortality from heart disease, stroke, and type 2 diabetes in the United States. JAMA 2017; 317: 912-924.
- 4. Neal B, Land MA, Woodward M. An update on the salt wars — genuine controversy, poor science, or vested interest? Curr Hypertens Rep 2013; 15: 687-693.
- 5. Mozaffarian D, Fahimi S, Singh GM, et al. Global sodium consumption and death from cardiovascular causes. N Engl J Med 2014; 371: 624-634.
- 6. Asaria P, Chisholm D, Mathers C, et al. Chronic disease prevention: health effects and financial costs of strategies to reduce salt intake and control tobacco use. Lancet 2007; 370: 2044-2045.
- 7. World Health Organization. Global status report on noncommunicable diseases 2014. Geneva: WHO, 2014. http://apps.who.int/iris/bitstream/10665/148114/1/9789241564854_eng.pdf?ua=1 (viewed Nov 2017).
- 8. Webster J, Trieu K, Dunford E, et al. Salt reduction in Australia: from advocacy to action. Cardiovasc Diagn Ther 2015; 5: 207-218.
- 9. Australian Bureau of Statistics. 4364.0.55.007. Australian Health Survey: nutrition first results — food and nutrients, 2011–12. May 2014. http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/4364.0.55.007Main+Features12011-12?OpenDocument (viewed Nov 2017).
- 10. Freedman LS, Commins JM, Moler JE, et al. Pooled results from 5 validation studies of dietary self-report instruments using recovery biomarkers for potassium and sodium intake. Am J Epidemiol 2015; 181: 473-487.
- 11. Rhodes DG, Murayi T, Clemens JC, et al. The USDA automated multiple-pass method accurately assesses population sodium intakes. Am J Clin Nutr 2013; 97: 958-964.
- 12. Brown IJ, Tzoulaki I, Candeias V, Elliott P. Salt intakes around the world: implications for public health. Int J Epidemiol 2009; 38: 791-813.
- 13. Ji C, Sykes L, Paul C, et al. Systematic review of studies comparing 24-hour and spot urine collections for estimating population salt intake. Rev Panam Salud Publica 2012; 32: 307-315.
- 14. Australian National Health and Medical Research Council Dietary Salt Study Management Committee. Fall in blood pressure with modest reduction in dietary salt intake in mild hypertension. Lancet 1989; 1: 399-402.
- 15. Beard TC, Eickhoff R, Mejglo ZA, et al. Population-based survey of human sodium and potassium excretion. Clin Exp Pharmacol Physiol 1992; 19: 327-330.
- 16. Beard TC, Woodward DR, Ball PJ, et al. The Hobart Salt Study 1995: few meet national sodium intake target. Med J Aust 1997; 166: 404-407. <MJA full text>
- 17. Jones G, Beard T, Parameswaran V, et al. A population-based study of the relationship between salt intake, bone resorption and bone mass. Eur J Clin Nutr 1997; 51: 561-565.
- 18. Bao DQ, Mori TA, Burke V, et al. Effects of dietary fish and weight reduction on ambulatory blood pressure in overweight hypertensives. Hypertension 1998; 32: 710-717.
- 19. Mori TA, Bao DQ, Burke V, et al. Docosahexaenoic acid but not eicosapentaenoic acid lowers ambulatory blood pressure and heart rate in humans. Hypertension 1999; 34: 253-260.
- 20. Hodge A, Patterson AJ, Brown WJ, et al. The Anti Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared with weighed food records in young to middle-aged women in a study of iron supplementation. Aust N Z J Public Health 2000; 24: 576-583.
- 21. Nowson CA, Morgan TO, Gibbons C. Decreasing dietary sodium while following a self-selected potassium-rich diet reduces blood pressure. J Nutr 2003; 133: 4118-4123.
- 22. Nowson CA, Worsley A, Margerison C, et al. Blood pressure response to dietary modifications in free-living individuals. J Nutr 2004; 134: 2322-2329.
- 23. Ward NC, Rivera J, Hodgson J, et al. Urinary 20-hydroxyeicosatetraenoic acid is associated with endothelial dysfunction in humans. Circulation 2004; 110: 438-443.
- 24. Hodgson JM, Burke V, Beilin LJ, Puddey IB. Partial substitution of carbohydrate intake with protein intake from lean red meat lowers blood pressure in hypertensive persons. Am J Clin Nutr 2006; 83: 780-787.
- 25. Margerison C, Nowson CA. Dietary intake and 24-hour excretion of sodium and potassium. Asia Pac J Clin Nutr 2006; 15(Suppl 3): S37.
- 26. Brinkworth GD, Wycherley TP, Noakes M, Clifton PM. Reductions in blood pressure following energy restriction for weight loss do not rebound after re-establishment of energy balance in overweight and obese subjects. Clin Exp Hypertens 2008; 30: 385-396.
- 27. Keogh JB, Brinkworth GD, Noakes M, et al. Effects of weight loss from a very-low-carbohydrate diet on endothelial function and markers of cardiovascular disease risk in subjects with abdominal obesity. Am J Clin Nutr 2008; 87: 567-576.
- 28. Dickinson KM, Keogh JB, Clifton PM. Effects of a low-salt diet on flow-mediated dilatation in humans. Am J Clin Nutr 2009; 89: 485-490.
- 29. Nowson CA, Wattanapenpaiboon N, Pachett A. Low-sodium dietary approaches to stop hypertension-type diet including lean red meat lowers blood pressure in postmenopausal women. Nutr Res 2009; 29: 8-18.
- 30. Lassale C, Guilbert C, Keogh J, et al. Estimating food intakes in Australia: validation of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) food frequency questionnaire against weighed dietary intakes. J Hum Nutr Diet 2009; 22: 559-566.
- 31. Ekinci EI, Cheong KY, Dobson M, et al. High sodium and low potassium intake in patients with type 2 diabetes. Diabetic Med 2010; 27: 1401-1408.
- 32. Charlton K, Yeatman H, Houweling F, Guenon S. Urinary sodium excretion, dietary sources of sodium intake and knowledge and practices around salt use in a group of healthy Australian women. Aust N Z J Public Health 2010; 34: 356-363.
- 33. Ireland DM, Clifton PM, Keogh JB. Achieving the salt intake target of 6 g/day in the current food supply in free-living adults using two dietary education strategies. J Am Diet Assoc 2010; 110: 763-767.
- 34. Keogh JB, Lange K, Syrette J. Comparative analysis of two FFQ. Public Health Nutr 2010; 13: 1553-1558.
- 35. Huggins CE, O’Reilly S, Brinkman M, et al. Relationship of urinary sodium and sodium-to-potassium ratio to blood pressure in older adults in Australia. Med J Aust 2011; 195: 128-132. <MJA full text>
- 36. Villani AM, Clifton PM, Keogh JB. Sodium intake and excretion in individuals with type 2 diabetes mellitus: a cross-sectional analysis of overweight and obese males and females in Australia. J Hum Nutr Diet 2012; 25: 129-139.
- 37. Australian Bureau of Statistics. 4364.0.55.007. Australian Health Survey: nutrition first results — food and nutrients, 2011–12. Table 1: Mean daily energy and nutrient intake. May 2014. http://www.abs.gov.au/ausstats/subscriber.nsf/log?openagent&Table%201%20Mean%20daily%20energy%20and%20nutrient%20intake.xls&4364.0.55.007&Data%20Cubes&C53378E733B57D2CCA257CD200146C93&0&2011-12&09.05.2014&Latest (viewed Nov 2017).
- 38. Petersen KS, Torpy DJ, Chapman IM, et al. Food label education does not reduce sodium intake in people with type 2 diabetes mellitus: a randomised controlled trial. Appetite 2013; 68: 147-151.
- 39. Land MA, Webster J, Christoforou A, et al. Salt intake assessed by 24 h urinary sodium excretion in a random and opportunistic sample in Australia. BMJ Open 2014; 4: e003720.
- 40. Blanch N, Clifton PM, Petersen KS, et al. Effect of high potassium diet on endothelial function. Nutr Metab Cardiovasc Dis 2014; 24: 983-989.
- 41. Turner KM, Clifton PM, Keogh JB. Sodium and potassium excretion are related to bone mineral density in women with coeliac disease. Clin Nutr 2015; 34: 265-268.
- 42. Nowson C, Lim K, Grimes C, et al. Dietary salt intake and discretionary salt use in two general population samples in Australia: 2011 and 2014. Nutrients 2015; 7: 10501-10512.
- 43. Petersen KS, Smith JM, Clifton PM, Keogh JB. Dietary intake in adults with type 1 and type 2 diabetes: validation of the Dietary Questionnaire for Epidemiological Studies version 2 FFQ against a 3-d weighed food record and 24-h urinalysis. Br J Nutr 2015; 114: 2056-2063.
- 44. Petersen KS, Clifton PM, Blanch N, Keogh JB. Effect of improving dietary quality on carotid intima media thickness in subjects with type 1 and type 2 diabetes: a 12-mo randomized controlled trial. Am J Clin Nutr 2015; 102: 771-779.
- 45. Lerchl K, Rakova N, Dahlmann A, et al. Agreement between 24-hour salt ingestion and sodium excretion in a controlled environment. Hypertension 2015; 66: 850-857.
- 46. Borenstein M, Higgins J, Hedges LV, Rothstein HR. Basics of meta-analysis: I2 is not an absolute measure of heterogeneity. Res Synth Methods 2017; 8: 5-18.
- 47. Trevena H, Neal B, Dunford E, Wu J. An evaluation of the effects of the Australian Food and Health Dialogue targets on the sodium content of bread, breakfast cereals and processed meats. Nutrients 2014; 6: 3802-3817.
- 48. Webb M, Fahimi S, Singh GM, et al. Cost effectiveness of a government supported policy strategy to decrease sodium intake: global analysis across 183 nations. BMJ 2017; 356: i6699.
- 49. Sadler K, Nicholson S, Steer T, et al. National Diet and Nutrition Survey: assessment of dietary sodium levels among adults (aged 19–64) in England, 2011. London: Department of Health, 2012. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/213420/Sodium-Survey-England-2011_Text_to-DH_FINAL1.pdf (viewed Nov 2017).
- 50. He FJ, Brinsden HC, MacGregor GA. Salt reduction in the United Kingdom: a successful experiment in public health. J Hum Hypertens 2014; 28: 345-352.
- 51. Land MA, Wu JH, Selwyn A, et al. Effects of a community-based salt reduction program in a regional Australian population. BMC Public Health 2016; 16: 388.
Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.