Is White Mulberry Leaf Safe? Herbal Supplement Is Linked to Death of Congressman's Wife

Coroner says Lori McClintock's death from gastroenteritis and dehydration was caused by ingesting white mulberry leaf. Many experts still believe the herbal supplement is safe.

Mulberries
Mulberries. Photo: Getty/Kilito Chan

Fast Facts

  • A “partially intact” white mulberry leaf was found in the stomach of Rep. Tom McClintock’s wife Lori, who died suddenly in December 2021.
  • White mulberry leaf is a traditional Chinese medicinal supplement that has been shown to lower glucose levels, high blood sugar, high blood pressure, and other ailments. 
  • Experts say that the plant is considered nontoxic and is generally safe to use, and more research needs to be done about McCormick’s death to determine how the leaf may have caused her death.

White mulberry leaf, a common herbal supplement that some claim prevents diabetes, obesity, and cardiometabolic issues, has been named as the potential cause of the December 2021 death of Lori McClintock, the wife of a California congressman.

The coroner's autopsy report, which was not initially released, but was obtained by KHN in July, said McClintock died from dehydration due to gastroenteritis. This stomach and intestinal inflammation was caused by "adverse effects of white mulberry leaf ingestion," the report said.

McClintock had been complaining of an upset stomach the day before she died, the coroner's report added. McClintock's husband Tom, who serves as a representative for the 4th District of California, said at her funeral that she had been "carefully dieting" prior to her death.

White mulberry leaf has traditionally been used in Chinese and Indian medicine, and is said to have a number of wide ranging health properties. And even following McClintock's death, experts say putting white mulberry's safety into question may be going too far.

Here's what we know about white mulberry leaves, the potential benefits and risks associated with taking it, and how to keep yourself safe.

Health Supplement With a Storied Past

White mulberry leaves are a dietary supplement that have been around for thousands of years.

The plant is originally native to China, but was brought to the U.S. in the 19th century as a host plant for silkworm farming. Now the plant is grown around the world, including in Canada, Australia, Turkey, and many other locations.

The white mulberry plant has a number of different uses. Though the fruit can be toxic when unripe, the ripe berries are often used to make jams or jellies. It can also be used as a natural colorant, and in some cosmetic products.

White mulberry leaf tea is frequently consumed in Asian countries, and in traditional medicine, the roots, leaves, and bark are thought to treat a wide variety of ailments, including fever, high blood sugar, cough, and high blood pressure, and improve hearing, brighten the eyes, and improve kidney and liver function.

Today, products that contain white mulberry extract, in addition to teas, are widely available for purchase.

It's not entirely clear in which form McClintock consumed the white mulberry, though the autopsy report, also obtained by KHN, said that a "partially intact" white mulberry leaf was found in her stomach.

Benefits and Concerns Associated With White Mulberry

Though benefits of white mulberry tea have been circulating for hundreds of years, recently some studies have proven some associations between ingesting the plant and health benefits.

A study from 2018 found that the leaves can protect against cardiometabolic risks, including high blood sugar levels, accumulation of lipids, inflammation, obesity, high blood pressure, and other issues that would otherwise affect the cardiovascular system.

White mulberry leaf extract can also lower glucose levels in rats, a 2020 study found, suggesting that it could help prevent diabetes. The same may be true for the white mulberry fruit. The leaves also helped prevent starch digestion, which could help diabetics avoid spikes in blood sugar.

The plant was also found to help reduce cholesterol levels, kill some oral pathogens, and reduce anxiety.

While white mulberry may seem like a miracle product, experts agree that more research needs to be done on the plant and its efficacy and safety in the body.

"They were never used for dieting," Ikhlas Khan, PhD, director of the National Center for Natural Products Research at the University of Mississippi, told Health. "It's not traditionally known [as a] reputable weight loss product." White mulberry certainly does have a number of health benefits—like relaxation and reducing sugar in the body—Khan said, but to treat it simply as a weight loss pill is taking the plant's benefits out of context.

The FDA doesn't have any sweeping guidance regarding white mulberry leaves or white mulberry extract—the agency cannot approve efficacy or safety of dietary supplements prior to the product being sold to the public, though it can regulate safety after the fact.

The FDA approved the product Reducose®5%, which includes white mulberry extract, as Generally Recognized as Safe (GRAS) in 2019. They ceased evaluation of a similar white mulberry product in 2021.

In addition to its litany of health benefits, there are a few reported negative side effects the research has tied to white mulberry leaves. However, it's unclear if they relate in any way to McClintock's case.

One study found that mild diarrhea, constipation, bloating, and dizziness can be associated with mulberry leaf extract, and eating unripe fruit and working frequently with white mulberry wood can cause illness. But the plant overall is not considered toxic, and there's nothing to suggest that the adverse effects experienced by McClintock are common. In the past decade, no deaths from white mulberry have been reported, The American Association of Poison Control Centers told KHN.

Not Necessarily a Cause for Alarm

Because of the rarity of this case, Khan says it's unlikely that casual users of white mulberry are at risk of severe illness or death from ingesting the berries or leaves. The best course of action is to use the supplement in moderation, and not overindulge if you don't see the pounds falling off.

"Like any other thing, you have to really think about [how] it can cause a problem," Khan said. "If somebody's taking a lot of leaves of mulberry which has a rough edge, and it's not fully digested, could it irritate your [gastrointestinal] tract? Yes it will."

Khan said that, in McClintock's case, we can't know how the white mulberry caused her gastroenteritis and dehydration with the facts that are available right now. But Khan suspects that she may have ingested too much of the plant—drinking white mulberry leaf tea and eating leaves—or she experienced a negative reaction between the white mulberry and some other kind of medication she may have been taking.

That link between the mulberry leaf in her system and McClintock's gastroenteritis and dehydration isn't fully explained in the coroner's report, which is a problem, said Daniel Fabricant, PhD, president and CEO of the Natural Products Association.

"If somebody said, 'Oh, by the gastric contents I know this person had this particular drug and died of that,' that wouldn't be adequate," Fabricant told Health. "They'd have to do bloodwork, they'd have to see what the pathology is, everything else. That none of that is present here. So I would say speculative at best."

He believes that her death should have been reported to the FDA so that the organization could do a full investigation into any potential issues with the product. A FDA spokesperson told KHN that they could not discuss possible investigations, so it's unclear if a report on McClintock's death was ever filed.

Going forward, McClintock's death will hopefully spur more action toward figuring out safety concerns with ingesting white mulberry, Khan said. People shouldn't necessarily be concerned if they use the supplement, but as always, it's best to be aware of what you're putting in your body and how it's affecting you.

With dietary supplements, Khan added, it's best to manage your expectations. People may be tempted to blow off negative side effects if they believe a product is working.

"Moderation, education, [and] being mindful of these things, because a lot of things are being used with traditional medicine [...] which are not traditionally used," Khan said. "That's something we're using for something new and for a different purpose in a different environments. They might not have the same effect."

With more research, hopefully we'll know more about white mulberry and how it may be connected to McClintock's death. But in the meantime, Khan said it's important to consult your doctor and keep an eye on how you're feeling after starting the dietary supplements, especially if you're taking other medications.

"Yes, we have a case now—nobody can say it cannot happen. But in general it does not happen because it has a pretty good safety," Khan said. "There are many many plants in traditional medicine which have safety concerns. But this one is not one of them."

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