Ginkgo biloba is one of the best known herbal medicines and is widely used to improve blood flow to the peripheries. Ginkgo biloba is included in the complementary treatment of peripheral arterial disease and hypertension in China as well as European countries. While Ginkgo biloba may have protective effects on the heart and circulation there is, as yet, no convincing evidence that it can lower blood pressure in adults with hypertension.
Contents Of This Article
Ginkgo biloba benefits
The distinctive, fan-shaped leaves of Ginkgo biloba contain unique antioxidants called ginkgolides and bilobalides. These improve blood flow by improving the elasticity of blood vessel walls, reducing platelet clumping and blood stickiness, as well as increasing red blood cell flexibility so they can squeeze through tiny blood vessels (capillaries) more easily. These improvements in blood flow have made Ginkgo biloba one of the most widely used herbal remedies to improve mental focus, memory, poor circulation, chilblains, Raynaud’s disease, tinnitus and erectile dysfunction. Together, these actions might be expected to lower blood pressure, too, but little research has been carried out to specifically test this.
Ginkgo biloba and blood pressure
Preclinical studies found that, in hypertensive rats, Ginkgo biloba treatments reduced their usual age-related increase in blood pressure so that average blood pressure readings were 28% lower in those that were treated compared with those that did not receive Ginkgo biloba.
And, when Gingko biloba was tested in 20 health people, aged 21 to 57 years, a dose of 120 mg Ginkgo biloba at bedtime, for 3 months, their average blood pressure readings reduced from 125/86 mmHg to 118/68 mmHg.
When Ginkgo biloba extracts were used in people with hypertension, however, these effects were less clear.
One large study was designed to compare the effects of Ginkgo biloba against placebo in preventing dementia in elderly people (average age 78 years), and also happened to measure blood pressure. Over 3,000 volunteers took part, of whom 54% had hypertension, 28% had prehypertension and 17% had normal blood pressure readings. As this study was not specifically set up to assess the effects of Ginkgo biloba on hypertension, all those diagnosed with hypertension were on appropriate antihypertensive medication and continued to take this. The volunteers were given either Ginkgo biloba (120 mg twice a day) or placebo, for an average of 6 years.
Overall, there were similar reductions in systolic and diastolic blood pressures in the Ginkgo biloba and placebo groups, but these amounted to changes of less than 1 mmHg. It’s possible that in this group of older people, antihypertensive treatment was already optimal, so that reductions were not seen. Another possibility is that age-related arterial stiffening that was already present made the Ginkgo biloba ineffective in achieving additional reductions in blood pressure.
Despite these negative results, the researchers recommended that future studies should test the effects of Ginkgo biloba in people under the age of 75 yrs, and assess its effects in people with prehypertension or hypertensive who are not taking antihypertensive medication.
Potentially positive studies
A large analysis of data from 9 studies, involving 1012 people with hypertension, compared the effects of adding Ginkgo biloba to existing antihypertensive treatments – either a calcium channel blocker (eg amlodipine), a beta blocker (eg metoprolol) or an angiotensin II receptor blocker (valsartan) but not Ginkgo biloba against placebo.
These studies found that Ginkgo biloba produced an additional blood pressure lowering effect by the end of treatment (8 weeks to 6 months) in six trials, but not in the other 3 trials. The researchers therefore felt unable to draw any firm conclusions on the effectiveness of Ginkgo biloba extracts for lowering high blood pressure without more convincing evidence.
Ginkgo biloba supplements
The usual dose is 120mg Ginkgo biloba extracts, once or twice a day. Select a product standardised to at least 24% ginkgo flavone glycosides.
NB Some supplements combine Ginkgo biloba with ginseng to improve mental focus – if your blood pressure is not well controlled, these are best avoided. If taking ginseng, monitor your blood pressure carefully in case it rises.
Ginkgo biloba side effects
No serious side effects were reported in the Ginkgo biloba trials mentioned above – those that did occur included abdominal discomfort and loss of appetite. Other side effects, such as flushing, dizziness and slight swelling of the lower limbs also occurred in those taking control (antihypertensive) treatments and were likely due to these medications.
Ginkgo biloba safety
If you are taking any prescribed medications, check with your doctor before taking Ginkgo biloba.
At usual doses of Ginkgo biloba, no effects on blood clotting have been found. As it has an antiplatelet effect, however, do not combine Ginkgo with mini-aspirin or other anticoagulants, except under medical advice.
If you have diabetes, monitor your blood glucose levels closely, as always, when starting a new supplement.
Image credits: brozova/bigstock; pixabay