It is a common ingredient in herbal teas, extracts, capsules, and pills, especially those marketed for weight loss and diabetes, and generally regarded as safe.
Autopsy results for Lori McClintock, who died last year, are raising questions about herbal supplements after findings implicated white mulberry leaf in her death. Lori McClintock was the wife of U.S. Rep. Tom McClintock.
According to the March 10 report from the Sacramento County coroner, which was recently obtained by Kaiser Health News (KNH) and released this week, the cause of death was gastroenteritis caused by “adverse effects of white mulberry leaf ingestion.”
The report noted that a “partially intact” white mulberry leaf was found in McClintock’s stomach, but it wasn’t clear from the autopsy report whether she drank a tea with white mulberry leaves, ate fresh or dried leaves, or took a dietary supplement containing white mulberry leaf, KHN reported. The death was ruled accidental in the autopsy, according to KHN.
Several toxicologists and doctors are skeptical that white mulberry leaf would cause death or even serious illness, however.
“After reading the actual report — which clearly states that it’s the cause — I still don't believe that's an accurate description of what happened,” says Pieter Cohen, MD, an associate professor at Harvard Medical School in Boston, who leads the dietary supplement research program at Cambridge Health Alliance. “If you eat any leaves, they’ll upset your stomach, but they won’t kill you,” Dr. Cohen says.
White mulberry is a tree that is native to China, Korea, and Japan, but is now found widely across Asia, Europe, and the Americas. It’s been used for centuries as a traditional Chinese herbal remedy for a wide range of ailments, including diabetes, heart disease, dementia, and obesity, says Kelly Johnson-Arbor, MD, co-medical director of the National Capital Poison Center in Washington, DC.
“White mulberry leaves contain many biologically active compounds, including alkaloids, flavonoids, and antioxidants that may have beneficial health effects,” Dr. Johnson-Arbor says.
When consumed, these compounds may help prevent cell damage, improve glucose levels, and enhance digestion, Johnson-Arbor says. White mulberry tree leaves are also rich in protein and fiber, and have been used as a food source for both people and animals, she adds. “In Korea, powdered white mulberry leaves are used to make ice cream!”
Decades of research have identified a wide range of potential health benefits associated with ingestion of white mulberry leaf, according to a review of studies to date that was published in 2021. Many of these studies, however, have been done in animals or contained too few people to draw broad conclusions about whether ingesting white mulberry leaf directly improves health, this review shows.
“White mulberry leaf has been studied for high cholesterol, obesity, impaired glucose tolerance, and diabetes; however, the evidence is generally insufficient,” says Grant Chu, MD, an assistant clinical professor of medicine at the David Geffen School of Medicine at the University of California in Los Angeles, and a medical reviewer for Everyday Health.
“The best available evidence on white mulberry leaf has been its role in diabetes,” Dr. Chu says. Compounds in white mulberry leaf may help slow the digestion of carbohydrates in the small intestines, Chu notes. This can help to manage blood sugar levels.
In one small clinical trial, scientists gave white mulberry leaf extract to 37 healthy adults and found it reduced blood sugar spikes that typically occur after consuming carbohydrates. Another clinical trial found white mulberry leaf extract helped control blood sugar in 12 adults with slightly elevated blood sugar levels.
And a separate clinical trial of 46 overweight adults found a low-calorie diet combined with white mulberry extract helped people shed significantly more weight than dieting on its own. People given mulberry extract lost about 10 percent of their body weight over three months, compared with about 3 percent for those in the control group that didn’t receive this extract.
Of course, these are all extremely small trials, and the evidence is insufficient to formally recommend white mulberry leaf for this purpose without additional rigorous research.
Over the past decade, there have been no deaths associated with the white mulberry plant reported in the United States, says Kaitlyn Brown, PharmD, clinical managing director of the American Association of Poison Control Centers in Arlington, Virginia.
Between 2011 and 2021, there were only nine reported cases of people seeking medical attention after ingesting white mulberry, Dr. Brown says. Seven of these patients had only minor symptoms and the other two had symptoms that were determined to be unrelated to the plant.
Most cases involved accidental ingestion by children, and the majority of kids experienced no symptoms or only minimal issues that didn’t require medical attention, Brown adds.
“Deaths or serious illnesses are very unlikely to occur from white mulberry ingestion,” Johnson-Arbor says. Mulberry and its extracts are minimally toxic, and symptoms that most often occur after ingestion are mild cases of nausea or abdominal discomfort, she adds.
Lori McClintock’s death marks the first on record attributed to white mulberry, several toxicology experts said. “To my knowledge, there have been no prior reports of serious side effects or death from white mulberry leaf ingestion in the literature until now,” Chu says.
McClintock’s case leaves a lot of unanswered questions, says Cohen, who reviewed the autopsy report. Normally, people who use white mulberry leaf as an herbal remedy take an extract — they don’t eat the leaves, Cohen says. Yet the autopsy claims there was a partial white mulberry leaf in her stomach. “I have no idea how they purportedly identified that,” Cohen says. “To have the actual leaf in one’s stomach something odd is going on — either the person is eating leaves or a supplement was made with whole leaves rather than an extract.”
“Not only is that odd, but I also find it very improbable that white mulberry leaves by themselves would lead to a death from dehydration — but that is what the coroner’s report claims,” Cohen says.
It’s possible that the mulberry leaf was ingested in a supplement that contained another substance that was the real cause of illness in this case, says Christopher Hoyte, MD, medical director of the Rocky Mountain Poison Center in Denver and an associate professor in emergency medicine at the University of Colorado. And it’s also possible that Lori McClintock had an undiagnosed medical condition that contributed to her death, Dr. Hoyte adds.
“Deaths that are directly attributable to mulberry leaf are so rare that it raises questions as to whether this substance is actually the culprit in this case,” Hoyte says.
The safest way to take herbal remedies like white mulberry leaf is to find a naturopath who works with a very high quality distributor of plants to properly make the extract, Cohen says. He advises steering clear of commercially produced supplements because what they say on the label won’t necessarily match what’s really in the product.
“White mulberry extracts and similar products that are sold as dietary supplements are not regulated by the U.S. Food and Drug Administration (FDA) for safety, purity, or quality, so the products may be contaminated with other chemicals that may be potentially poisonous,” Johnson-Arbor says.
Any supplements you buy should have a USP seal on the package, indicating they’ve been independently tested to verify the ingredients, potency, and lack of contaminants, Johnson-Arbor advises.
With white mulberry leaf, any symptoms you experience that go beyond a little mild nausea or abdominal discomfort are a sign you may have consumed something else — and that it’s time to contact poison control for help, Johnson-Arbor says.
You can get free expert advice 24 hours a day online at www.Poison.org or by phone at 800-222-1222.
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