NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

  • This publication is provided for historical reference only and the information may be out of date.

This publication is provided for historical reference only and the information may be out of date.

Cover of Dietary Supplements in Adults Taking Cardiovascular Drugs

Dietary Supplements in Adults Taking Cardiovascular Drugs

Comparative Effectiveness Reviews, No. 51

Investigators: , ND, MSc, , PharmD, , MSc, , MSc, , MPH, , MD, MSc, , PhD, , PhD, , MD, , MD, , BKin, , MLS, , BA, and , MBBS, MMedSc, MPhil.

Author Information
Rockville (MD): Agency for Healthcare Research and Quality (US); .
Report No.: 12-EHC021-EF

Structured Abstract


A substantial proportion of patients with cardiovascular diseases use dietary supplements in anticipation of benefit. This also poses risks of adverse events from supplement-drug interactions and nonadherence associated with polypharmacy.


For supplements commonly used by patients with cardiovascular disease, we examined benefits, harms, and effects on cardiovascular drug pharmacokinetics of coadministration of dietary supplements with cardiovascular drugs. We also sought evidence regarding variability among subgroups, and of statistical interactions between supplements and drugs.

Data Sources:

We searched MEDLINE®, Embase, the Cochrane Library, International Bibliographic Information on Dietary Supplements (IBIDS), and Allied and Complementary Medicine Database (AMED), as well as gray literature, from inception to September 2011.

Study Selection:

Following a predefined protocol, two reviewers included experimental and observational studies comparing a supplement plus cardiovascular drug versus drug alone published in English or German; other languages were excluded due to concerns with study quality and applicability.

Data Extraction:

One reviewer extracted data into a standardized electronic form, assessed study risk of bias, graded the strength of the body of evidence, and reported its applicability. Study risk of bias and strength of evidence regarding gradable outcomes were independently verified, as was a random 10 percent subset of all data.

Data Synthesis:

Sixty-seven randomized controlled trials, two controlled clinical trials, and one observational study contributed evidence of limited validity in highly selected populations. Evidence was insufficient for all gradable clinical efficacy and harms outcomes (e.g., mortality, thrombotic events, serious adverse events) because there were few, small studies per supplement. One pragmatic trial in women showed no benefit from coadministering vitamin E with aspirin on a composite cardiovascular outcome. Evidence for most intermediate outcomes of efficacy was insufficient or of low strength and suggested no effect. Notable findings were incremental improvement of triglyceridemia with omega-3 fatty acid supplementation, stabilization of international normalized ratio with vitamin K added to warfarin therapy, and improved high-density lipoprotein cholesterol (HDL-C) with added garlic. Clinically nonsignificant or otherwise inconclusive changes were noted for pharmacokinetic outcomes.


The evidence base principally consisted of underpowered short-term studies in selected populations, generally with moderate risk of bias.


Limitations of the evidence base precluded meaningful conclusions across most supplement-drug combinations. Low-strength evidence indicates benefits of omega-3 fatty acids, vitamin K, and garlic coadministration on specific intermediate outcomes. Evidence regarding harms was inconclusive. Care providers and researchers should query supplement use to improve care and to facilitate research regarding drug-supplement interactions.


Prepared for: Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services1, Contract No. 290-2007-10059-I, Prepared by: University of Ottawa Evidence-based Practice Center, Ottawa, Ontario

Suggested citation:

Seely D, Kanji S, Yazdi F, Tetzlaff J, Singh K, Tsertsvadze A, Sears ME, Tricco A, Ooi TC, Turek M, Tsouros S, Skidmore B, Daniel R, Ansari MT. Dietary Supplements in Adults Taking Cardiovascular Drugs. Comparative Effectiveness Review No. 51. (Prepared by the University of Ottawa Evidence-based Practice Center under Contract No. HHSA 290-2007-10059-I.) AHRQ Publication No. 12-EHC021-EF. Rockville, MD: Agency for Healthcare Research and Quality. April 2012.

This report is based on research conducted by the University of Ottawa Evidence-based Practice Center (EPC) under contract to the Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Contract No. HHSA 290-2007-10059-I). The findings and conclusions in this document are those of the authors, who are responsible for its contents; the findings and conclusions do not necessarily represent the views of AHRQ. Therefore, no statement in this report should be construed as an official position of AHRQ or of the U.S. Department of Health and Human Services.

The information in this report is intended to help health care decisionmakers—patients and clinicians, health system leaders, and policymakers, among others—make well-informed decisions and thereby improve the quality of health care services. This report is not intended to be a substitute for the application of clinical judgment. Anyone who makes decisions concerning the provision of clinical care should consider this report in the same way as any medical reference and in conjunction with all other pertinent information, i.e., in the context of available resources and circumstances presented by individual patients.

This report may be used, in whole or in part, as the basis for development of clinical practice guidelines and other quality enhancement tools, or as a basis for reimbursement and coverage policies. AHRQ or U.S. Department of Health and Human Services endorsement of such derivative products may not be stated or implied.

None of the investigators has any affiliations or financial involvement that conflicts with the material presented in this report.


540 Gaither Road, Rockville, MD 20850; www‚Äč

Bookshelf ID: NBK97368PMID: 22696775


Similar articles in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...