The claim: Cilantro removes heavy metals from the brain
A popular social media claim alleges cilantro is more than just a popular herb for cooking.
"Cilantro removes toxic heavy metals from the brain," reads the text of a Facebook post shared Dec. 29.
The post generated over 5,000 interactions and close to 1,600 shares in less than two weeks. Several other social media users shared this post as well.
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But the claim doesn't tell the whole story.
Experts told USA TODAY researchers are still exploring the effectiveness of cilantro's healing properties in removing potential heavy metals from the brain.
USA TODAY reached out to the social media user who shared the post for comment.
Brain hasn't been studied enough
USA TODAY reached out to 80 experts about the claim but received only four responses. Jane Flinn, director of cognitive and behavioral neuroscience at George Mason University, said in an email the idea seemed novel to her.
"I have to admit I had never heard of this," Flinn said. "Plants can absorb metals but I don't know how it would get it out of the brain."
Dr. Maida Galvez, professor of environmental medicine and public health at Mount Sinai, said in an email there is insufficient evidence to prove the claim.
Through a search on PubMed, a search engine containing over 33 million research studies, USA TODAY found two articles that explore cilantro and heavy metal in the brain. Both studies used lead, a common heavy metal, as their primary agent.
Exposure to lead can produce oxidative stress, an imbalance of antioxidants that protect against cell and tissue breakdown, according to Medical News Today. A 2014 study concluded that hydro-alcoholic seed extract from cilantro can alleviate lead-induced oxidative stress in certain tissues of rat brains.
The study did not look at the properties of cilantro as a whole. And it focused on damage done after a heavy metal enters the brain rather than whether cilantro can remove heavy metals.
A more recent study published in 2021 found cilantro provided protection against both oxidative stress and negative changes in brain structure that lead caused in the brains of mice. It did not address whether cilantro removes heavy metals directly from the brain.
Chris D'Adamo, director of the Center for Integrative Medicine at the University of Maryland, said there is no certainty the same effects would present in humans, too, since the study was in mice.
Several other studies have found cilantro has an impact on heavy metals elsewhere in the body.
A 2010 study found that cilantro reduced the tissue levels of lead in the testes of mice to some extent. Researchers also published a study three years ago that concluded the intake of cilantro leaf extract contributed to a decrease of oxidative stress in the kidney, likely due to reduced concentration of heavy metals.
“More studies would be helpful to confirm the findings, but there is some foundation to the claim being made about cilantro in light of this study and how we know it chelates heavy metals throughout the body," said D'Adamo.
How heavy metals enter the brain
Heavy metals can get into the brain from exposure to environmental toxins, which can leach into food, drinking water and the air, D' Adamo said.
These metals also have the ability to cross the blood-brain barrier, a feature of the human nervous system that defends the brain from pathogens and toxins in the blood, according to a 2015 study.
The effects of heavy metal in the brain vary. Lead can result in a range of neurodevelopmental problems, such as attention deficit hyperactivity disorder and decreased IQ in children, Galvez said.
Mercury can "alter brain functions and lead to tremors, shyness, irritability, memory problems and changes in hearing or vision," according to a 2019 study.
Scientists have sought ways to reduce heavy metals in the body, given these negative outcomes.
One treatment to remove heavy metals from the body is chelation therapy, in which a solution is injected into the bloodstream that binds with the properties of a metal, according to University of Michigan Health.
Randomized control trials in children with lead poisoning have demonstrated the effectiveness of chelation therapy at blood lead levels of 45 micrograms per deciliter or higher, Galvez said.
A 2019 research study shows how chelation therapy can act as a "therapeutic agent" for neurotoxicity caused by heavy metals. Researchers are still exploring the efficacy of chelation therapy in removing heavy metals in the brain.
Our rating: Missing context
Based on our research, we rate MISSING CONTEXT the claim that cilantro removes heavy metals from the brain. Scientists USA TODAY spoke to weren't aware of any studies that directly proved this claim and said more research is needed. However, some studies have found cilantro or its extracts have a positive effect on heavy metal levels in the body and brains of rodents.
Our fact-check sources:
Dr. Maida Galvez, Jan. 5, Email exchange with USA TODAY
Chris D'Adamo, Jan. 5, Phone interview with USA TODAY
PubMed, accessed Jan. 11, Morphohistometric analysis of the effects of Coriandrum sativum on cortical and cerebellar neurotoxicity
The University of Queensland, accessed Jan. 11, What is the blood-brain barrier?
IntechOpen, June 19, 2019, Mechanism and Health Effects of Heavy Metal Toxicity in Humans
PubMed, accessed Jan. 11, Report: Central nervous system (CNS) toxicity caused by metal poisoning: Brain as a target organ
University of Michigan Health, Sept. 23, 2020, Chelation Therapy
National Institute of Environmental Health Sciences, July 16, Neurodegenerative Diseases
PubMed, accessed Jan. 14
PubMed, accessed Jan. 11, Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review
Jane Flinn, Jan. 7, Email exchange with USA TODAY
Dr. Marijane Hynes, Jan. 5, Email exchange with USA TODAY
PubMed, accessed Jan. 11, EDTA Chelation Therapy for the Treatment of Neurotoxicity
PubMed, accessed Jan. 11, Prophylactic efficacy of Coriandrum sativum (Coriander) on testis of lead-exposed mice
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This article originally appeared on USA TODAY: Fact check: Unproven claim that cilantro removes heavy metal in brain