Pine bark (Pinus spp.) extract for treating chronic disorders

Using pine bark supplements to help treat a variety of chronic diseases

Review question

Can pine bark antioxidant supplements help to treat chronic diseases?

Background

The main ingredients in pine bark extract supplements are proanthocyanidins, which are antioxidants. These supplements are marketed to prevent or treat a wide range of chronic diseases. This is an update of a previously published review, where we assessed how well these supplements work for treating chronic diseases, as well as their safety.

Search date

The evidence is current to 30 September 2019.

Study characteristics

We included 27 studies (1641 participants) across 10 chronic diseases. These included: asthma (two studies; 86 participants), attention deficit hyperactivity disorder (ADHD) (one study; 61 participants), heart disease and risk factors (seven studies; 332 participants), chronic venous insufficiency (leg veins not working effectively; two studies; 60 participants), diabetes (six studies; 336 participants), erectile dysfunction (three studies; 227 participants), female sexual dysfunction (one study; 75 participants), osteoarthritis (cartilage damage in joints; three studies; 293 participants), osteopenia (beginning of bone mass loss; one study; 44 participants) and traumatic brain injury (one study; 56 participants). Two of the studies were conducted exclusively in children; the others were in adults. Studies compared pine bark supplements with placebo (i.e. a dummy supplement) or non‐antioxidant interventions and participants were randomly selected for one treatment or the other. The duration of treatment ranged from four weeks to six months.

Key results

For most outcomes across the different chronic diseases we only included one study with a small number of participants. In adults with asthma, we do not know whether pine bark extract increases lung function, improves asthma symptoms or increases the number of people able to stop using albuterol inhalers (a specific type of asthma pump).
In children with ADHD, we do not know whether pine bark supplements decrease inattention and hyperactivity (assessed by parents and teachers) or whether it increases co‐ordination and concentration.
In people with heart disease we do not know if pine bark supplements decrease blood pressure and LDL cholesterol (the bad type) or whether it increases HDL cholesterol (the good type).
In adults with chronic venous insufficiency we do not know whether pine bark supplements decrease pain, increase the number of people free of pain, or how well doctors think the treatment works. In people with type 2 diabetes, we do not know whether pine bark supplements improve blood sugar levels or HbA1c levels (the long‐term marker for measuring blood sugar control); we also do not know if pine bark supplements decrease HbA1c in people with type 1 or type 2 diabetes.
In men with erectile dysfunction, we do not know if pine bark supplements increase erectile function. Similarly, in women with sexual dysfunction, we do not know if pine bark supplements increase sexual satisfaction or reduce pain.
In adults with osteoarthritis, it is not clear if pine bark supplements improve pain, swelling or stiffness in the knee, or whether it decreases the use of anti‐inflammatory drugs. We also do not know if pine bark supplements increase bone formation in postmenopausal women with weakened bones. Lastly, in people with a traumatic brain injury, it is not clear if pine bark supplements improve memory and post‐concussion symptoms .

For most comparisons, studies did not report outcomes of hospital admissions or serious adverse events.

With the available studies, we cannot clearly say how well (or not) pine bark supplements work and whether they are safe.

Quality of the evidence

The overall risk of bias was low for four studies, high for one and unclear for 22 studies. By this we mean the extent to which the methods used in a study enable it to determine the truth. The certainty of evidence was very low for all outcomes across all chronic diseases in the included studies.