Is ginkgo biloba really effective when it comes to brain health? The evidence is thin.

Ginkgo biloba might be challenging to pronounce, but finding it in the supplement aisle is easy.

Why are extracts from this ancient tree popular? And is there any evidence to support its health claims?

Background

Ginkgo biloba (pronounced: GINK-go bill-OH-buh) is a large shade tree native to China that has distinctive, fan-shaped leaves. Also called the maidenhair tree or living fossil, it is one of the world’s oldest living tree species, dating to over 250 million years ago.

Ginkgo was introduced to the United States in the late 1700s, though some trees in China are estimated to be 3,500 years old.

The extracts of ginkgo leaves contain bioactives including flavonoids and terpenoids that are thought to have health benefits. Flavonoids have antioxidant qualities. Terpenoids might help improve blood flow.

Ginkgo extracts are sold as dietary supplements in the form of capsules, teas and liquid extracts. A standard form is a concentrated supplement known as EGb-761 extract.

Evidence

Ginkgo extracts traditionally have been used for a range of medicinal purposes, often purported to improve brain function and memory.

But clinical evidence to support those claims is inconsistent. The largest clinical trial of ginkgo — the Ginkgo Evaluation of Memory study — involved more than 3,000 adults 75 or older who were given more than 120 milligrams of ginkgo or a placebo twice a day.

The study found ginkgo wasn’t effective in lowering the overall incidence of dementia or Alzheimer’s disease in older adults with and without mild cognitive impairment.

And there were no reductions in blood pressure or cardiovascular disease.

More research is needed to better determine what role it might have in cognitive function and other health conditions.

Safety, side effects

Ginkgo generally is considered safe when taken in moderate amounts.

But there can be minor side effects — like upset stomach, dizziness and constipation.

Raw or roasted ginkgo seeds can be poisonous and should not be consumed.

The supplements also aren’t recommended for women who are pregnant or breastfeeding.

Interactions

Ginkgo might interact with blood thinners, diabetes management drugs, anticonvulsants, statins and antidepressants.

Pease consult with your physician to discuss whether ginkgo is appropriate for you.

Environmental Nutrition is anndependent newsletter written by nutrition experts.