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Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f1378 (Published 04 April 2013) Cite this as: BMJ 2013;346:f1378
  1. Nancy J Aburto, scientist1,
  2. Sara Hanson, intern1,
  3. Hialy Gutierrez, independent consultant2,
  4. Lee Hooper, senior lecturer in research synthesis and nutrition3,
  5. Paul Elliott, professor4,
  6. Francesco P Cappuccio, Cephalon professor of cardiovascular medicine & epidemiology5
  1. 1Nutrition Policy and Scientific Advice Unit, Department of Nutrition for Health and Development, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland
  2. 2200 Wheeler Avenue, Staten Island, NY 10314, USA
  3. 3Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
  4. 4Department of Epidemiology and Biostatistics and MRC-HPA Centre for Environment and Health, Imperial College London, London, UK
  5. 5World Health Organization Collaborating Centre for Nutrition, Warwick Medical School, Coventry CV2 2DX, UK
  1. Correspondence to: N J Aburto nancy.aburto{at}wfp.org
  • Accepted 18 February 2013

Abstract

Objective To conduct a systematic review of the literature and meta-analyses to fill the gaps in knowledge on potassium intake and health.

Data sources Cochrane Central Register of Controlled Trials, Medline, Embase, WHO International Clinical Trials Registry Platform, Latin American and Caribbean Health Science Literature Database, and the reference lists of previous reviews.

Study selection Randomised controlled trials and cohort studies reporting the effects of potassium intake on blood pressure, renal function, blood lipids, catecholamine concentrations, all cause mortality, cardiovascular disease, stroke, and coronary heart disease were included.

Data extraction and synthesis Potential studies were independently screened in duplicate, and their characteristics and outcomes were extracted. When possible, meta-analysis was done to estimate the effects (mean difference or risk ratio with 95% confidence interval) of higher potassium intake by using the inverse variance method and a random effect model.

Results 22 randomised controlled trials (including 1606 participants) reporting blood pressure, blood lipids, catecholamine concentrations, and renal function and 11 cohort studies (127 038 participants) reporting all cause mortality, cardiovascular disease, stroke, or coronary heart disease in adults were included in the meta-analyses. Increased potassium intake reduced systolic blood pressure by 3.49 (95% confidence interval 1.82 to 5.15) mm Hg and diastolic blood pressure by 1.96 (0.86 to 3.06) mm Hg in adults, an effect seen in people with hypertension but not in those without hypertension. Systolic blood pressure was reduced by 7.16 (1.91 to 12.41) mm Hg when the higher potassium intake was 90-120 mmol/day, without any dose response. Increased potassium intake had no significant adverse effect on renal function, blood lipids, or catecholamine concentrations in adults. An inverse statistically significant association was seen between potassium intake and risk of incident stroke (risk ratio 0.76, 0.66 to 0.89). Associations between potassium intake and incident cardiovascular disease (risk ratio 0.88, 0.70 to 1.11) or coronary heart disease (0.96, 0.78 to 1.19) were not statistically significant. In children, three controlled trials and one cohort study suggested that increased potassium intake reduced systolic blood pressure by a non-significant 0.28 (−0.49 to 1.05) mm Hg.

Conclusions High quality evidence shows that increased potassium intake reduces blood pressure in people with hypertension and has no adverse effect on blood lipid concentrations, catecholamine concentrations, or renal function in adults. Higher potassium intake was associated with a 24% lower risk of stroke (moderate quality evidence). These results suggest that increased potassium intake is potentially beneficial to most people without impaired renal handling of potassium for the prevention and control of elevated blood pressure and stroke.

Footnotes

  • We gratefully acknowledge the support of funding bodies (see below), along with the countless hours provided by WHO Nutrition Guidance Expert Advisory Group members in providing input and comments on the document. We are also thankful to all stakeholders who provided their feedback on scoping the review.

  • Contributors: The WHO Nutrition Guidelines Expert Advisory Group Subgroup on Diet and Health discussed and developed the priority questions to be covered by the review in March 2011, and subsequently developed the protocol to answer those questions. NJA, HG, and SH ran the searches. HG and SH carried out the assessment of inclusion, data extraction, and validity assessment, with input from NJA. HG and NJA did the data analyses. NJA developed the first GRADE evidence profiles. NJA prepared the first draft of the report submitted for review by the WHO Nutrition Guidelines Expert Advisory Group Subgroup on Diet and Health, with support from HG and SH. The WHO Nutrition Guidelines Expert Advisory Group Subgroup on Diet and Health reviewed earlier drafts and contributed to the analysis and GRADE assessment. NJA wrote the first draft of the manuscript. LH, PE, and FPC provided substantial intellectual input on research methods and interpretation of results. All authors read, provided input on, and agreed the final draft of the manuscript. WHO agreed with the publication of this systematic review in a scientific journal as it serves as the background evidence review for establishing the WHO guideline on potassium intake for adults and for children and should, therefore, be widely available. NJA is the guarantor.

  • Funding: Funding for this review came from various sources, including WHO funds, the Kidney Evaluation Association Japan, and the governments of Japan and the Republic of Korea. PE receives support from the National Institute for Health Research (NIHR) Biomedical Research Centre based at Imperial College Healthcare NHS Trust and Imperial College London. PE is an NIHR Senior Investigator. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

  • Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: LH, FPC, and PE received funding from WHO to attend NUGAG Subgroup of Diet and Health meetings; PE receives support from the National Institute for Health Research (NIHR) Biomedical Research Centre based at Imperial College Healthcare NHS Trust and Imperial College London; FPC is an unpaid member of Consensus Action on Salt and Health and World Action on Salt and Health, an unpaid advisor to WHO and the PAHO, an individual member of the National Heart Forum, and a former member of the Executive Committee and trustee of the British Hypertension Society; PE is an unpaid member of CASH and WASH and an unpaid advisor to WHO; no further financial support from any organisation for the submitted work that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work. NJA was a staff member of the WHO at the time this work was completed; the author alone is responsible for the views expressed in this publication, and they do not necessarily represent the views, decisions, or policies of WHO.

  • Ethical approval: Not needed.

  • Data sharing: The datasets are available from the corresponding author at nancy.aburto{at}wfp.org.

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