madman
Super Moderator
Background Pine bark (Pinus spp.) extract is rich in bioflavonoids, predominantly proanthocyanidins, which are antioxidants. Commercially-available extract supplements are marketed for preventing or treating various chronic conditions associated with oxidative stress. This is an update of a previously published review.
Objectives To assess the efficacy and safety of pine bark extract supplements for treating chronic disorders.
Search methods We searched three databases and three trial registries; the latest search: 30 September 2019. We contacted the manufacturers of pine bark extracts to identify additional studies and hand-searched bibliographies of included studies.
Selection criteria Randomised controlled trials (RCTs) evaluating pine bark extract supplements in adults or children with any chronic disorder.
Data collection and analysis Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias. Where possible, we pooled data in metaanalyses. We used GRADE to evaluate the certainty of evidence. Primary outcomes were participant- and investigator-reported clinical outcomes directly related to each disorder and all-cause mortality. We also assessed adverse events and biomarkers of oxidative stress.
Main results This review included 27 RCTs (22 parallel and five cross-over designs; 1641 participants) evaluating pine bark extract supplements across 10 chronic disorders: asthma (two studies; 86 participants); attention deficit hyperactivity disorder (ADHD) (one study; 61 participants), cardiovascular disease (CVD) and risk factors (seven studies; 338 participants), chronic venous insufficiency (CVI) (two studies; 60 participants), diabetes mellitus (DM) (six studies; 339 participants), erectile dysfunction (three studies; 277 participants), female sexual dysfunction (one study; 83 participants), osteoarthritis (three studies; 293 participants), osteopenia (one study; 44 participants) and traumatic brain injury (one study; 60 participants). Two studies exclusively recruited children; the remainder recruited adults. Trials lasted between four weeks and six months. Placebo was the control in 24 studies. The overall risk of bias was low for four, high for one, and unclear for 22 studies.
Authors' conclusions Small sample sizes, limited numbers of RCTs per condition, variation in outcome measures, and poor reporting of the included RCTs mean no definitive conclusions regarding the efficacy or safety of pine bark extract supplements are possible.
A U T H O R S ' C O N C L U S I O N S
Implications for practice Pine bark extract supplements are marketed worldwide as a treatment for a wide variety of chronic disorders (American Botanical Council 2010). Our review shows that currently, the available evidence is not sufficient to support claims regarding its benefit or to assure its safety in the chronic conditions we came across. It is important for users or potential users to be cognizant of this. Furthermore, healthcare professionals need to be aware of the diverse range of chronic conditions for which pine bark extract supplements are promoted, and the lack of evidence for efficacy and safety aspects, so that they are better equipped to guide individuals in deciding whether or not to include pine bark extract supplements as part of the management of their condition.
Implications for research Despite the inclusion of 27 randomized controlled trials (RCTs) that assessed the efficacy of pine bark supplements for treating a variety of chronic disorders, the certainty of the evidence is very low. Well designed, adequately powered, and well-reported RCTs of pine bark extract supplements are lacking. However, as meaningful amounts of proanthocyanidins and antioxidants can be obtained from a healthy diet (Benzie 2014), this raises the question whether it is worth spending further research funds on more RCTs, and whether it is fair to expose more individuals to research that is not making a meaningful contribution to the overall body of evidence. However, should future trials be conducted, careful attention should be given to the outcomes to ensure that selected outcomes are clinically relevant to people and are measured in a standardized manner.
Objectives To assess the efficacy and safety of pine bark extract supplements for treating chronic disorders.
Search methods We searched three databases and three trial registries; the latest search: 30 September 2019. We contacted the manufacturers of pine bark extracts to identify additional studies and hand-searched bibliographies of included studies.
Selection criteria Randomised controlled trials (RCTs) evaluating pine bark extract supplements in adults or children with any chronic disorder.
Data collection and analysis Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias. Where possible, we pooled data in metaanalyses. We used GRADE to evaluate the certainty of evidence. Primary outcomes were participant- and investigator-reported clinical outcomes directly related to each disorder and all-cause mortality. We also assessed adverse events and biomarkers of oxidative stress.
Main results This review included 27 RCTs (22 parallel and five cross-over designs; 1641 participants) evaluating pine bark extract supplements across 10 chronic disorders: asthma (two studies; 86 participants); attention deficit hyperactivity disorder (ADHD) (one study; 61 participants), cardiovascular disease (CVD) and risk factors (seven studies; 338 participants), chronic venous insufficiency (CVI) (two studies; 60 participants), diabetes mellitus (DM) (six studies; 339 participants), erectile dysfunction (three studies; 277 participants), female sexual dysfunction (one study; 83 participants), osteoarthritis (three studies; 293 participants), osteopenia (one study; 44 participants) and traumatic brain injury (one study; 60 participants). Two studies exclusively recruited children; the remainder recruited adults. Trials lasted between four weeks and six months. Placebo was the control in 24 studies. The overall risk of bias was low for four, high for one, and unclear for 22 studies.
Authors' conclusions Small sample sizes, limited numbers of RCTs per condition, variation in outcome measures, and poor reporting of the included RCTs mean no definitive conclusions regarding the efficacy or safety of pine bark extract supplements are possible.
A U T H O R S ' C O N C L U S I O N S
Implications for practice Pine bark extract supplements are marketed worldwide as a treatment for a wide variety of chronic disorders (American Botanical Council 2010). Our review shows that currently, the available evidence is not sufficient to support claims regarding its benefit or to assure its safety in the chronic conditions we came across. It is important for users or potential users to be cognizant of this. Furthermore, healthcare professionals need to be aware of the diverse range of chronic conditions for which pine bark extract supplements are promoted, and the lack of evidence for efficacy and safety aspects, so that they are better equipped to guide individuals in deciding whether or not to include pine bark extract supplements as part of the management of their condition.
Implications for research Despite the inclusion of 27 randomized controlled trials (RCTs) that assessed the efficacy of pine bark supplements for treating a variety of chronic disorders, the certainty of the evidence is very low. Well designed, adequately powered, and well-reported RCTs of pine bark extract supplements are lacking. However, as meaningful amounts of proanthocyanidins and antioxidants can be obtained from a healthy diet (Benzie 2014), this raises the question whether it is worth spending further research funds on more RCTs, and whether it is fair to expose more individuals to research that is not making a meaningful contribution to the overall body of evidence. However, should future trials be conducted, careful attention should be given to the outcomes to ensure that selected outcomes are clinically relevant to people and are measured in a standardized manner.
