Downloaded from http://heart.bmj.com/ on July 17, 2015 - Published by group.bmj.com
Heart Online First, published on July 7, 2015 as 10.1136/heartjnl-2015-308288 PostScript
CORRESPONDENCE
Coffee brewing technique as a confounder in observational studies Choi et al1 describe an association between moderate coffee consumption and lower prevalence of subclinical coronary atherosclerosis. This is consistent with a growing body of evidence that supports this finding. A similar, large prospective study of over 400 000 participants demonstrated that coffee consumption was inversely associated with both total and cause-specific mortality, specifically heart disease.2 These findings were independent of the caffeine content of the coffee, suggesting that other compounds might be important. Coffee contains many other compounds that might be responsible for the observations of these studies, including antioxidants, but the naturally occurring diterpenes, cafestol and kahweol are of significant interest. Both are found in Arabica beans and released during the brewing process of regular and decaffeinated coffee. The amount in coffee preparations varies enormously depending on the brewing
method used. Instant and drip-filtered coffee contains insignificant quantities of diterpenes, which are removed by industrial processing and the lipid-binding properties of filter paper, respectively. In contrast, high concentrations occur in French press, Scandinavian boiled and Turkish-style coffees.3 Diterpenes have pleiotropic effects including elevating serum lipids, antioxidant, anti-inflammatory, proapoptotic and antiangiogenic properties.2–4 While this work contributes to the evidence that coffee may confer health benefits, future studies need to account for coffee brewing technique as a significant confounding variable.
Provenance and peer review Not commissioned; internally peer reviewed. Data sharing statement The manuscript may be distributed as the journal sees fit. To cite Hingston CD, Wise MP. Heart Published Online First: [ please include Day Month Year] doi:10.1136/heartjnl-2015-308288
▸ http://dx.doi.org/10.1136/heartjnl-2014-306663 Heart 2015;0:1. doi:10.1136/heartjnl-2015-308288
Christopher D Hingston, Matt P Wise Department of Adult Critical Care, University Hospital of Wales, Cardiff, South Glamorgan, UK Correspondence to Dr Christopher D Hingston, Department of Critical Care Directorate, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK; [email protected] Twitter Follow Christopher Hingston at @chris__ hingston Contributors Both authors contributed equally to the preparation of this manuscript, have agreed the content and this manuscript consists of our own work and ideas. Competing interests None declared.
Heart Month 2015 Vol 0 No 0
REFERENCES 1
2
3
4
Choi Y, Chang Y, Ryu S, et al. Coffee consumption and coronary artery calcium in young and middle-aged asymptomatic adults. Heart 2015;101:686–91. Freedman ND, Park Y, Abnet CC, et al. Association of coffee drinking with total and cause-specific mortality. N Engl J Med 2012;366:1891–904. Urgert R, van der Weg G, Kosmeijer-Schuil TG, et al. Levels of the cholesterol-elevating diterpenes cafestol and kahweol in various coffee brews. J Agric Food Chem 1995;43:2167–72. Cárdenas C, Quesada AR, Medina MA. Anti-angiogenic and anti-inflammatory properties of kahweol, a coffee diterpene. PLoS One 2011;6: e23407.
1
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd (& BCS) under licence.
Downloaded from http://heart.bmj.com/ on July 17, 2015 - Published by group.bmj.com
Coffee brewing technique as a confounder in observational studies Christopher D Hingston and Matt P Wise Heart published online July 7, 2015
Updated information and services can be found at: http://heart.bmj.com/content/early/2015/07/07/heartjnl-2015-308288
These include:
References Email alerting service
This article cites 4 articles, 1 of which you can access for free at: http://heart.bmj.com/content/early/2015/07/07/heartjnl-2015-308288 #BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
Heart Online First, published on July 7, 2015 as 10.1136/heartjnl-2015-308288 PostScript
CORRESPONDENCE
Coffee brewing technique as a confounder in observational studies Choi et al1 describe an association between moderate coffee consumption and lower prevalence of subclinical coronary atherosclerosis. This is consistent with a growing body of evidence that supports this finding. A similar, large prospective study of over 400 000 participants demonstrated that coffee consumption was inversely associated with both total and cause-specific mortality, specifically heart disease.2 These findings were independent of the caffeine content of the coffee, suggesting that other compounds might be important. Coffee contains many other compounds that might be responsible for the observations of these studies, including antioxidants, but the naturally occurring diterpenes, cafestol and kahweol are of significant interest. Both are found in Arabica beans and released during the brewing process of regular and decaffeinated coffee. The amount in coffee preparations varies enormously depending on the brewing
method used. Instant and drip-filtered coffee contains insignificant quantities of diterpenes, which are removed by industrial processing and the lipid-binding properties of filter paper, respectively. In contrast, high concentrations occur in French press, Scandinavian boiled and Turkish-style coffees.3 Diterpenes have pleiotropic effects including elevating serum lipids, antioxidant, anti-inflammatory, proapoptotic and antiangiogenic properties.2–4 While this work contributes to the evidence that coffee may confer health benefits, future studies need to account for coffee brewing technique as a significant confounding variable.
Provenance and peer review Not commissioned; internally peer reviewed. Data sharing statement The manuscript may be distributed as the journal sees fit. To cite Hingston CD, Wise MP. Heart Published Online First: [ please include Day Month Year] doi:10.1136/heartjnl-2015-308288
▸ http://dx.doi.org/10.1136/heartjnl-2014-306663 Heart 2015;0:1. doi:10.1136/heartjnl-2015-308288
Christopher D Hingston, Matt P Wise Department of Adult Critical Care, University Hospital of Wales, Cardiff, South Glamorgan, UK Correspondence to Dr Christopher D Hingston, Department of Critical Care Directorate, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK; [email protected] Twitter Follow Christopher Hingston at @chris__ hingston Contributors Both authors contributed equally to the preparation of this manuscript, have agreed the content and this manuscript consists of our own work and ideas. Competing interests None declared.
Heart Month 2015 Vol 0 No 0
REFERENCES 1
2
3
4
Choi Y, Chang Y, Ryu S, et al. Coffee consumption and coronary artery calcium in young and middle-aged asymptomatic adults. Heart 2015;101:686–91. Freedman ND, Park Y, Abnet CC, et al. Association of coffee drinking with total and cause-specific mortality. N Engl J Med 2012;366:1891–904. Urgert R, van der Weg G, Kosmeijer-Schuil TG, et al. Levels of the cholesterol-elevating diterpenes cafestol and kahweol in various coffee brews. J Agric Food Chem 1995;43:2167–72. Cárdenas C, Quesada AR, Medina MA. Anti-angiogenic and anti-inflammatory properties of kahweol, a coffee diterpene. PLoS One 2011;6: e23407.
1
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd (& BCS) under licence.
Downloaded from http://heart.bmj.com/ on July 17, 2015 - Published by group.bmj.com
Coffee brewing technique as a confounder in observational studies Christopher D Hingston and Matt P Wise Heart published online July 7, 2015
Updated information and services can be found at: http://heart.bmj.com/content/early/2015/07/07/heartjnl-2015-308288
These include:
References Email alerting service
This article cites 4 articles, 1 of which you can access for free at: http://heart.bmj.com/content/early/2015/07/07/heartjnl-2015-308288 #BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
