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Syst Rev. 2018 Jul 18;7(1):100. doi: 10.1186/s13643-018-0764-z.

Dietary intakes of flavan-3-ols and cardiovascular health: a field synopsis using evidence mapping of randomized trials and prospective cohort studies.

Author information

1
Tufts Center for Clinical Evidence Synthesis, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Box 63, 800 Washington Street, Boston, MA, 02111, USA. graman@tuftsmedicalcenter.org.
2
Tufts Center for Clinical Evidence Synthesis, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Box 63, 800 Washington Street, Boston, MA, 02111, USA.
3
Tufts University Friedman School of Nutrition Science and Policy, 150 Harrison Ave, Boston, MA, 02111, USA.
4
Agricultural Research Service, U.S. Department of Agriculture, Beltsville Human Nutrition Research Center, Beltsville, MD, USA.
5
Department of Nutrition and Preventive Medicine, Norwich Medical School, University of East Anglia, Norwich, UK.

Abstract

BACKGROUND:

There is considerable interest in the impact of increased flavan-3-ol intake on cardiovascular disease (CVD) and diabetes outcomes. Through evidence mapping, we determined the extent of the evidence base to initiate a future systematic review investigating the impact of flavan-3-ol intake on CVD and diabetes outcomes.

METHODS:

We developed a research protocol, convened a technical expert panel (TEP) to refine the specific research questions, conducted a systematic search in multiple databases, double-screened abstracts and full-text articles, performed data extractions, and synthesized the data. We focused on randomized controlled trials (RCTs) and prospective cohort studies which assessed intakes of flavan-3-ol from foods, beverages, and supplement/extract sources on biomarkers and clinical outcomes of CVD and diabetes.

RESULTS:

Of 257 eligible articles, 223 and 34 publications contributed to 226 RCTs and 39 prospective cohort studies, respectively. In RCTs, the most frequently studied interventions were cocoa-based products (23.2%); berries (16.1%); tea in the form of green tea (13.9%), black tea (7.2%), or unspecified tea (3.6%); and red wine (11.2%). Mean total flavan-3-ol intake was highest in the cocoa-based trials (618.7 mg/day) and lowest in the interventions feeding red wine (123.7 mg/day). The most frequently reported outcomes were intermediate biomarkers including serum lipid levels (63.4%), blood glucose (50.9%), blood pressure (50.8%), flow-mediated dilation (21.9%), and high-sensitivity C-reactive protein (21.9%). The included 34 prospective cohort studies predominantly examined exposures to flavan-3-ols (26%), cocoa-based products (23.2%), berries (16.1%), and green tea (13.9%) and CVD incidence and mortality.

CONCLUSION:

Through a systematic, evidence-based approach, evidence mapping on flavan-3-ol intake and CVD outcomes demonstrated sufficient data relating to flavan-3ol intake and biomarkers and clinical outcomes of CVD and diabetes. The current evidence base highlights the distribution of available data which both support the development of a future systematic review and identified the research need for future long-term RCTs.

SYSTEMATIC REVIEW REGISTRATION:

At present, evidence mapping is not eligible for registration on the international prospective register of systematic reviews (i.e., PROSPERO).

KEYWORDS:

Berries; Cardiovascular disease; Cinnamon; Cocoa; Diabetes; Evidence mapping; Flavan-3-ols; Lipids; Red wine; Tea

PMID:
30021626
PMCID:
PMC6052707
DOI:
10.1186/s13643-018-0764-z
[Indexed for MEDLINE]
Free PMC Article

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