Herbal medicine experts and nutraceutical industry leaders have challenged a Sacramento County coroner’s conclusion that white mulberry leaf (Morus alba)—an herb with a long record of safe use—caused the death of Loretta McClintock, wife of Congressman Tom McClintock (R-CA4).

McClintock died unexpectedly on Dec. 15, 2021 at the age of 61. Her husband had returned home for the Congressional holiday recess and found his wife unresponsive.

The initial death certificate, issued Dec. 20, said the immediate cause of death was “pending,” and mentioned an “accident pending investigation.” A Dec. 16 autopsy report insinuated that McClintock’s death might be due to severe dehydration, secondary to gastroenteritis, caused by “ingested white mulberry leaf.”

In a subsequent report dated Mar. 10, 2022, the coroner definitively declared that McClintock’s death was due to “adverse effects of white mulberry leaf ingestion.” This report—and an updated death certificate—were not made public until July. The story made national headlines after an Aug. 24 report by Samantha Young in Kaiser Health News (KHN).

The coroner’s assertion that mulberry leaf killed McClintock was based on the fact that during the autopsy, investigators found a 1 1/8 inch by 1 7/8 inch fragment of a leaf in McClintock’s stomach, which they claimed to be white mulberry. But the report gave no information on the analytical methods used to identify the plant in question.

That did not stop the Kaiser reporter from laying blame for McClintock’s death on mulberry, or from stating that the tragedy “underscores the risks of the vast, booming market of dietary supplements and herbal remedies, which have grown into a $54 billion industry in the United States—one that both lawmakers and health care experts say needs more government scrutiny.”

Predictably, the Kaiser article unleashed a deluge of “me-too” media reports, most of which were poorly researched, and which parroted the message that McClintock’s sad demise was caused by the “poorly regulated” and “highly-influential” dietary supplements industry.” Egregious headlines, like one from Newsweek “How Did Herbal Remedy Kill Lori McClintock?” peppered news feeds in the weeks after the Kaiser report.

Industry organizations, including the United Natural Products Alliance (UNPA), the American Herbal Products Association (AHPA), and the Natural Products Association (NPA), responded quickly and forcefully, pointing out that the leaf in question may not actually be mulberry, and that the fragment found in McClintock’s stomach almost certainly did not come from a supplement.

The nature of the plant material the coroners found suggests that McClintock had eaten uncooked, unprocessed leaf, which may—or may not—be mulberry.

Safe History of Use

Mulberry leaves are widely used as fodder for cattle, goats, and other livestock, and they are the principal food for silkworms. They are rich in polyphenols and anthocyanidins. Though seldom used as a human food, especially in the U.S., the leaves are a common remedy in Traditional Chinese Medicine. Known as Sang Shèn Zǐ or Sang Ye, mulberry leaves are typically ingested as teas or ground powder form, and prescribed to treat lung and liver conditions. 

More recently, supplement makers and some functional medicine practitioners have promoted the herb, or extracts from it, for glucose regulation, lipid reduction, and weight management, based on clinical studies suggesting it has promise for these indications.

Roy Upton, president of the American Herbal Pharmacopoeia (AHP), noted that while human ingestion of raw mulberry leaves is not unheard of, particularly in Asia, it is highly unusual especially in the U.S. The leaves are bitter and generally unpleasant to the taste.

Upton also pointed out that in TCM herbal practice, the dose range for white mulberry leaves is 3.5 to 9 g, and “there’s no history of human toxicity with this.” He added that animal studies show the plant to be safe at levels as high as 4 g per kg.

The Sacramento coroners gave no reason for their initial suspicion that the leaf fragment they found was mulberry. The report contained no mention of, for example, a family member stating that Lori McClintock was using this herb, or that a package containing mulberry leaves was found in her home. The Kaiser story and other media reports indicated that McClintock had begun dieting and exercising not long before she died. But none mentioned that she was using mulberry or any other herbs.

Trial By Media

The barrage of negative reports blaming supplements for the death of a Congressman’s wife is a classic example of “trial by media,” which is unfortunately all too common in the way that the mainstream press covers herbs, nutrients, and other supplements.

Honorably, Kaiser Health News published a follow up article on Sep. 14, also by Samantha Young, that more or less admitted the case against mulberry is weak.

Young wrote: “Sacramento County Coroner Kimberly Gin has not explained—nor provided records that explain—why she determined white mulberry leaf led to the dehydration that killed McClintock at age 61, fueling skepticism among a variety of experts.”

“There is no other reference to her use of white mulberry leaves, supplements, extracts, powders—or any other method of ingesting the plant—in the documents the coroner’s office has released relating to the case.”

A Questionable Conclusion

In describing the contents of McClintock’s gastrointestinal tract, the coroner’s report stated: “The esophagus is intact throughout. The stomach is not distended. It contains 50 cc of tan fluid. The mucosa is smooth and glistening. Portions of tablets and capsules cannot be discerned in the stomach. A partial plant leaf is present within the contents. The external and in situ appearance of the small intestine and colon are unremarkable. The small intestine and colon are opened along the anti-mesenteric border and are unremarkable. The appendix is present.”

There are several major holes in the coroner’s report. There is no description of the contents of the intestines, though it would be logical to think that if a leaf fragment was found in the stomach, more might be present in the small or large intestines.

There’s no description of any morphologic changes indicative of gastroenteritis, which is usually caused by microbial pathogens, not by herbs. Neither is there a listing of other prescription, OTC, or supplement products that McClintock may have been using, or a positive, definitive statement that she was not in fact taking any other drugs or supplements.

The conclusion that the Congressman’s wife died from dehydration seems based largely on analysis done by NMS Labs, a forensic toxicology lab in Horsham, PA. NMS tests showed elevated vitreous sodium, creatinine, and urea nitrogen. But the coroners failed to describe how the leaf fragment in question would have caused a fatal level of dehydration.

Chief Pathologist Jason Tovar, MD, who signed the autopsy report, declined a request for an interview. Head coroner Kimberly Gin has categorically refused to comment on the case in the media.

Vague Methodology

The coroners did not say how they identified the “partial plant leaf” they found inside McClintock as white mulberry.

Presumably, they based that conclusion on a Dec. 29, 2021 report from botanist Alison Colwell, PhD, curator of the UC Davis Center for Plant Diversity. In her letter to the supervising deputy coroner, Colwell stated: “I picked up a leaf fragment from your office yesterday for identification […] This leaf fragment was taken from the stomach of a deceased person. It measures 1 1/8” by 1 7/8” and includes a portion of the center of one leaf with a portion of one major vein and two adjacent secondary veins joined by a single bronchiodromous loop. The leaf tissue retains flexibility and some green color, so the leaf was likely ingested when fresh.

“In comparing this leaf fragment to fresh leaves and to our extensive library of pressed specimens, we determine that this leaf fragment is a match to Morus alba, the white mulberry. The sample matches white mulberry specimens in all traits examined: upper and lower leaf surface texture, hairiness, venation pattern, intercostal tissue patterning, the frequency, size and shape of the stomata and the embeddedness of the veins relative to the plane of the leaf.”

Colwell concluded her report by stating definitively, “White mulberry is not toxic. I compared the specimen to lethally toxic species that are known to be planted or are native in the Sacramento area and found no matches.”

Colwell declined to comment on the case.

Mistaken Identity?

Elan Sudberg, who heads Alkemist Labs—one of the nation’s leading analytical testing labs for botanical identity and quality—said the morphologic features described in the UC Davis report are overly general and not specific to white mulberry.

“The characteristics used to identify the leaf are not unique to this genus and species. They are shared by many plants,” said Sudberg, who has 26 years of experience in botanical microscopy. 

“There are things called cystoliths, which are found only in maybe 10 types of plants. I can think of only one other medicinal herb, besides mulberry leaf, that has cystoliths and that is nettle leaf.”

Cystoliths are specialized cells within certain plants that contain calcium carbonate or other substances that serve as plant defense mechanisms. Another distinctive feature of Morus alba is the presence of oxalate crystals within parenchymal cells.

“These two features are unique to this genus and species,” Sudberg said. “They’re not found in spinach, or watercress, or lettuce, or cilantro, or other common plants that people ingest. They are unique and describable features (of mulberry leaf). Yet they were not described in the findings, which makes me question said findings.”

“You remark on the remarkable, not on the common features,” he added.

Many have raised the question of whether advanced chromatography or genomic fingerprinting techniques could potentially provide a more definitive identification of the leaf fragment. The answer is maybe, at least in theory.

But Sudberg, whose lab specializes in high-performance liquid, and thin-layer chromatography (HPLC, HPTLC), said it is questionable whether a leaf sample subjected to gastric juices for an unknown period of time would yield reliable results.

Further, these techniques are not like the fictional Star Trek tricorders, which can be pointed at an unknown substance and automatically return a definitive identification. When doing chromatography or gene testing, one must compare the sample’s phytochemical or genetic profile against known reference standards. That means one must have a specific target in mind, explained Sudberg. 

Again, the coroner’s report did not give any reason for the a priori suspicion that the leaf was from Morus alba. And if chromatography or genome tests were part of the identification process, why weren’t the data included in the report.

Swift Industry Response

Industry leaders rightfully took issue with the media claims that supplements were involved in McClintock’s death—an extrapolation that even the coroner’s office itself did not make.

A formal statement issued by AHPA called out the media using the occasion of a tragic death to, “challenge the robust regulation of dietary supplements by the federal government, despite the fact that there is no information in the report showing that Mrs. McClintock’s assumed consumption of white mulberry leaf was in the form of a dietary supplement.”

AHPA noted that, “The majority of clinical trials studying white mulberry leaf report no adverse events.” Further, AHPA stressed that, “No causality can be inferred from the facts reported in the coroner’s report.”

Rick Kingston, PharmD, a clinical toxicologist and adverse event expert at SafetyCall International is quoted in the AHPA position paper stating, “There is no weight of evidence with multiple streams of data implicating white mulberry.” He added that the Sacramento autopsy findings raise more questions than answers.

It was largely due to the industry’s outcry, and to the measured voices of intelligent and well-informed experts, that Samantha Young and Kaiser issued the follow-up article.

The Wrong Herb to Bully

KHN’s recanting is a positive step, but the truth is many media outlets—including some of the major ones—have been getting away with shoddy reporting on supplements for decades. This time, the case was so weak that industry experts had little trouble pushing back.

“They picked the wrong herb to try to bully,” said Stefan Wypyszyk, managing director of the North American division of Phynova, a global botanical ingredient supplier.

Phynova’s flagship ingredient is called Reducose, a patented water extract of white mulberry leaves. Understandably, the company is concerned about the shade that the McClintock case—and the careless media coverage—has cast on this beneficial herb.

Wypyszyk noted that there are eight published clinical trials on the health benefits of Reducose, primarily in the context of glucose regulation and carbohydrate absorption.

In the wake of the McClintock tragedy, Wypyszyk and his colleagues compiled all the safety, toxicology, and efficacy data for their ingredient. The report stated that, “One study specifically explored gastrointestinal tolerability of Reducose over 24-hours post-consumption. The study was a dose-ranging study that explored half-dose, recommended dose, and double the recommended dose, and reported that there was no difference in the frequency or severity of any GI symptoms compared with placebo, at any dose.”

Beyond Phynova’s branded mulberry extract, a 2016 meta-analysis of 13 clinical trials looking at various forms of supplemental mulberry leaf showed no significant differences in relative risk of adverse events. The minor effects that were reported included headache, nausea, unusual sense of fullness, and diarrhea. There were no serious, let alone life-threatening reactions.

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"The mulberry saga also shows that a swift, informed, and scientifically-grounded response from experts within the industry can have positive impact. The KHN retraction story came about largely because knowledgeable herb experts spoke up with a unified voice and a strong case for questioning the Sacramento coroner’s conclusion. They did so in a firm but friendly way that did not personally vilify the KHN reporter or anyone else."

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Important Lessons

We may never know what actually caused the death of Loretta McClintock. Rep. McClintock himself and other family members have said little. There is no police report on record, and scant public information about the setting or circumstances prior to her passing. The Sacramento coroner’s office is refusing to discuss the matter.

But it is clear that the evidence implicating white mulberry is inconclusive at best.

There are several important lessons which the industry can draw from the McClintock case. One is that some coroners and other medical experts are quick to blame dietary supplements as causes for otherwise unexplained deaths. And monkey-see, monkey-do media outlets will mindlessly echo these claims.

Further, the media tends to blame the entire supplement industry for a potential problem with one particular product or ingredient.

This is not to say there are no problems within the supplements industry, that the media always gets it wrong, or that industry objections are always justified.

But could you imagine major news outlets reporting on an auto recall by stating that the car industry needs to be reined in? Or headlines screaming about a rogue food industry because a Salmonella outbreak landed dozens of people in the hospital? Or a spate of deaths associated with a particular prescription drug prompting a broad-stroke vilification of the pharmaceutical industry?

No, of course not. That never happens. Yet, news agencies will take the slightest hint of a problem with an herb or dietary ingredients as an opportunity to bash the entire industry, and even the entirety of holistic/functional medicine. It’s a reality we need to acknowledge and confront.

Critics of holistic medicine and natural products often accuse its advocates of playing loose and fast with facts in order to promote non-conventional modalities. Those critics are notably silent when a county coroner uses the thinnest of evidence to blame an unfortunate death on a generally safe herb.

The mulberry saga also shows that a swift, informed, and scientifically-grounded response from experts within the industry can have positive impact. The KHN retraction story came about largely because knowledgeable herb experts spoke up with a unified voice and a strong case for questioning the Sacramento coroner’s conclusion. They did so in a firm but friendly way that did not personally vilify the KHN reporter or anyone else.

It’s a winning strategy for sure. 

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About the Author: Erik Goldman is co-founder and editor of Holistic Primary Care: News for Health & Healing, a quarterly medical publication reaching about 60,000 physicians and other healthcare professionals nationwide. He is also co-producer of the Practitioner Channel Forum, the nation’s leading conference focused on opportunities and challenges in the practitioner segment of the dietary supplement industry.