Ginkgo biloba is a popular herbal supplement that some suggest can boost brain power and prevent Alzheimer’s disease. It is currently one of the top-selling herbs in the United States. However, a new study suggests that it may damage your liver and even cause cancer.
During the study, researchers deposited solutions containing ginkgo biloba extract into the stomachs of rats five times a week for two years. Some groups received stronger concentrations of ginkgo than others. Afterward, they discovered that the rats with the most ginkgo exposure had a higher chance of developing liver damage, which included liver lesions and hypertrophy (having an abnormally large liver).
In addition to liver damage, the researchers also noticed an increased rate of cancers of the thyroid, along with abnormal growths in the nasal tissue. This comes as a shock to many in the medical community, as this supplement was generally considered safe for most people, except those who were taking blood thinners, as ginkgo can restrict the blood clotting process.
Ginkgo has been found to expand blood vessels by inhibiting nitric oxide, the chemical responsible for vascular contraction. Many believe that this process can increase blood flow to the brain and improve memory. As a result, the herb has been used as a supplement for thousands of years and as an ingredient in drinks and teas – despite the fact that it isn’t approved for use in food and beverages by the US Food and Drug Administration (FDA). However, since it’s a supplement, it’s regulated differently compared to drugs or medications. The FDA doesn’t require manufacturers of supplements to register their products in order to reach the market.
Its properties have led researchers to test gingko to treat headaches, concentration problems, mood, eyesight, hearing, asthma and digestion. However, the research on the herb’s effectiveness for these ailments remains inconclusive.
However, in light of the new data, some experts are now discouraging its use. Some cite the lack of solid evidence that ginkgo actually works. “Since the evidence in support of ginkgo is so weak, this really should be the nail in the coffin of yet another supplement,” writes Dr. Henry. S. Lodge, MD, Professor of Medicine at Columbia University Medical Center and member of Dr. Oz’s Medical Advisory Board.
Critics of the study point out that because the test subjects were rats, there’s still no way to know how ginkgo will affect humans. Some also claim that the ginkgo used in the study is different that was is available on store shelves – and was used in higher doses than one would get in a tea, drink or supplement.
The National Toxicology Program, the organization behind the study, plans to collect more information on how gingko affects humans and identify components of the compounds to assess how it can cause damage.