“For more than 130 years, the National Geographic Society has been at the forefront of combining science, exploration, and storytelling to better understand the world around us,” a fundraising letter begins. “National Geographic Society is determined to be the organization people around the world can turn to for information they can trust.” Its long and storied history well known, few people would doubt the Society’s sincerity when it describes its “passion for science.”
It was surprising, therefore, to learn that the National Geographic Society (NGS) has in the past decade published at least six books that, according to their covers, promote natural healing remedies, home remedies, and medicinal herbs, all of which “treat common ailments.” Do these publications align with the well-deserved, science-based reputation of the NGS?
This article reviews those six books, all readily available on the internet (see sidebar for full titles). The focus here is on the publications themselves as a whole; I make no attempt to engage in the debate regarding the value of “alternative medicine,” although references to it cannot be completely avoided.
First, the Good News
The books are well written, beautifully illustrated, and, when indicated, often provide appropriate cautions regarding their recommendations. They offer suggestions about many subjects that may be helpful to readers, including information regarding nutrition, lifestyle, personal care (deodorants, etc.), and household tips (floor cleaners, etc.). But the focus of the books, and this article, is medicinal herbs. The thorough discussions about the botany, preparation, usefulness, and precautions of using herbal substances can serve as a powerful resource.
Plants have been a source of medicinal products for centuries. Many of today’s important pharmaceuticals are derived directly from plants. The Guide to Medicinal Herbs categorizes and characterizes seventy-two plants that have been used therapeutically. The books are forthright in advising the reader that there are important caveats. Complete Guide to Natural Home Remedies, for example, notes that some remedies are supported by evidence that is largely anecdotal, that they may have side effects, and that they can interfere with prescription medications. In a statement found frequently throughout the books, the reader is advised, “If you’re not sure that a natural remedy might be safe for you, consult your health care provider.” These warnings are appropriate.
In many respects, the books are praiseworthy. But that is not the end of the story.
The Not-Good News
Although warnings are present, they are not helpful, as the books proceed to advise taking substances that have little or no evidence of safety or effectiveness and ignore that there is essentially no way for a person to know in advance whether a “natural remedy would be safe” for them. Furthermore, the reader cannot be certain whether the advice is good, unsupported, inaccurate, false, or harmful; it’s all mixed together.
Problems occur when the authors overreach and promote ideas that are not supported by evidence and when the books are inconsistent with each other. The important question I seek to answer is: Do these books provide reliable advice about curing or preventing illness? Or, in the vocabulary used by the books, do these “remedies” for “ailments” actually work?
Cause for Concern
Skepticism begins with the book covers. Five of the six covers do not identify an author—which is unusual for such books—and have the word remedies in the title. A remedy is something that cures or relieves a disease or bodily disorder. When used as a verb, it means “to cure or heal, as by medicinal treatment.” Judging by the covers (which, in this case, you can), it appears that the NGS books are offering cures for disease.
Two of the publications’ introductions state that “we have sought the best ideas from around the world and put them to the test of current science.” Another states, “This book showcases the … herbs, plants, and essential oils that can help you treat diseases and ailments.” From statements such as these and other promises of “remedies,” it is clear that the publications are claiming to offer scientifically based advice about treating and preventing disease.
The small-print “Note to Readers” at the beginning of each book, however, in disclaiming “any liability whatsoever,” states that “the author and publisher are not rendering medical or other professional advice.” The note warns to “consult a health care professional to address any health concerns specific to you.” These advisories contradict the obvious message of the books. The statements “Treat illness nature’s way” and “how to employ natural remedies to cure or control common physical ailments” are more examples that belie the “Note to Readers” claim. The argument that explaining how to treat medical conditions does not constitute medical advice is specious and disingenuous.
The self-contradictions are concerning. Medical textbooks do not have disclaimers advising the reader that they are not rendering medical advice. Medications are tested and proved effective and safe by reproducible evidence. Rather than warn the reader that its claims are not medical advice, if the NGS is to remain true to its stated commitment to science, it shouldn’t recommend remedies that lack a sufficient evidence base to support the claims.
The warning, by itself, throws into doubt the veracity, and thus the value, of the remedies. Given that the NGS books therefore clearly reside in the arena of “alternative medicine,” perhaps their “remedies” should be called “alternative remedies.” (Some say that, like “alternative facts,” there is no such thing as “alternative medicine”—if the remedy had sufficient evidence of effectiveness and safety, it would simply be called “medicine.”)
Description of Problems
The problems with the NGS remedies enterprise can be classified into six features, any one of which would disqualify a publication from legitimately claiming that its advice about how to treat illness has been put to the “test of current science.”
Lack of actual evidence. Though it is understood that these books are intended for a lay audience, it would increase confidence in their messages if at least a few references to supporting data were provided. Phrases frequently found throughout the books include “some studies point to,” “research has shown that,” “animal studies show,” “researchers are looking at,” and the like. It would be valuable, and increase the believability of the books, if actual references to specific studies would at least occasionally be cited to back up the claims being made. In the over 1,400 pages that compose the six books, there are no references to the scientific literature.
Overreach stretching credulity. After proclaiming that “Research verifies that these vegetables offer a range of nutrients,” the next sentence states, “They also provide antibiotic, antibacterial, antiviral, antioxidant, and anticancer properties, making them useful as remedies for skin infections, restoring vigor, curing sleeplessness, easing migraines, and even combating cancer.” Next, we’re told that adding these to our diet “could provide the following health benefits,” including lowering high blood pressure, normalizing an irregular heartbeat, slowing down the progression of Alzheimer’s disease, reducing bone loss in postmenopausal women, and decreasing indigestion and nausea.
Beyond this probably harmless fantastical litany, however, there is a statement that raises a serious concern: that these plants “act as detoxifying agents, especially for those suffering from jaundice.” Anyone who has jaundice needs to see a physician immediately to find out why. Delay literally could be fatal.
Not a shred of evidence is presented to support even one of these many claims. If half of them were true, the great value to humankind would likely be widely known. What is this magic substance? It’s water chestnut.
Is there evidence? A search of the medical literature turned up one 2014 study that found extracts of water chestnut lowered sugar in mice. Ironically, lowering high sugar is not a benefit the NGS book claims. No studies of the health effects of water chestnuts in humans could be found. The claim for lowering blood pressure apparently comes from the fact that water chestnuts contain potassium (as do many foods), not that a study showed eating water chestnuts lowers blood pressure. One health-related study found that “microcystins can accumulate in water chestnuts, which is a potential hazard for human health.” (Microcystins are a toxin produced by fresh water algae.)
Internally contradictory. “Because of its potent anti-inflammatory properties, cat’s claw is used to treat joint problems such as those occurring in osteoarthritis and rheumatoid arthritis.” Two pages later, rheumatoid arthritis is listed as one of three “Therapeutic Uses” for cat’s claw. Remarkably, immediately adjacent, in the next column on that page, there is a boxed warning stating, “Those with autoimmune diseases … should not use cat’s claw.” Rheumatoid arthritis is an autoimmune disease and, if not properly treated, can damage joints. Delay in receiving evidence-based treatment can harm people who have rheumatoid arthritis.
Bad advice. In a section on dairy, claims are made that full-fat cheese and butter are not only okay to eat but may offer health benefits. The rationale is due to a misunderstanding of cholesterol metabolism. Contrary to the book’s statements and inferences, saturated fat (which cheese and butter are full of) increases the concentration of low-density lipoprotein cholesterol (LDL-C—the “bad” kind), which is associated with increased risk of heart disease and death.
Failure to inform about alternatives. One of the books advises that you can treat athlete’s foot with lavender essential oil because of the oil’s antifungal action. Two methods of preparation are described. Mix three drops of lavender oil with one teaspoon of sweet almond or grapeseed oil, or combine two teaspoons of tincture of benzoin with five drops of lavender oil and five drops of thyme oil. What is not mentioned is that clotrimazole, for example, one of several inexpensive, generic, over-the-counter creams, has been proven to quickly and completely eliminate the athlete’s foot fungus. Its safety and efficacy has been tested, its purity is assured by a regulated production process, and it is more convenient, as all that is required is squeezing cream out of the tube. No mixing of drops required.
This benign example causes one to question what service NGS is providing by describing an inferior method of eliminating foot fungus (if it works at all) and not mentioning an established, tested, proven safe and effective, easier-to-use treatment. A thirty-gram tube of clotrimazole can be purchased online for $3.19. The lavender oil alone costs more than twice as much.
Inconsistency among the books. The NGS books recommend a variety of substances to treat high blood pressure (hypertension), which are listed here by book.
- Nature’s Best Remedies (2019): Fennel, water chestnut, saffron, hibiscus tea, juicing or smoothies with ingredients apple, beet, celery, cucumber, ginger.
- Guide to Medicinal Herbs (2010): Grape seed extract, parsley, stevia, hibiscus, and chocolate.
- Complete Guide to Natural Home Remedies (2012): Beet juice is mentioned in the foreword, but hypertension is not addressed elsewhere in the 384-page book.
- Nature’s Best Remedies (2015, reissued 2018): Grape seed extract; warnings against using parsley and hibiscus if taking high blood pressure medication.
- Healing Remedies (2014): The “Common Ailments” chapter has no section on cardiovascular conditions at all, and it has no index.
- Natural Home Remedies (2017, reissued 2019): Also offers nothing about high blood pressure, even in its “remedies for common ailments” chapter. It does mention parsley, but only to recommend it for bad breath.
- No single remedy is recommended in all four books that mention any treatment for hypertension.
- One of the books recommends parsley or hibiscus and another also recommends hibiscus, but a third warns against parsley and hibiscus if taking hypertension medication. The two recommending parsley and hibiscus do not mention the warning.
- Two of the books offer nothing for hypertension.
These inconsistencies, contradictions, and omissions would never occur in medical textbooks because there is overwhelming evidence that many medications successfully treat hypertension. It is telling that there was no single herbal remedy for hypertension that all four books recommended. All truly scientific, evidence-based texts discussing hypertension would agree that hydrochlorothiazide, for example, lowers blood pressure. Over 116 million people, 46 percent of U.S. adults, have hypertension. It is a major contributor to cardiovascular disease, which is the leading cause of death in the United States for both men and women. Not mentioning it in books purporting to offer advice about common ailments is bewildering and irresponsible. Where is the science and reason for trust that the NGS claims?
Butterbur (Petasites hybridus)
It is interesting and instructive to examine in depth the NGS books’ treatment of any one herb. Selecting the first plant described in the National Geographic Guide to Medicinal Herbs introduces us to butterbur. It turns out this plant is an excellent example, because it demonstrates the many pros and cons of “natural” and “herbal” medicine.
Conditions claimed to be improved by butterbur. As is true for many of the herbs discussed in these books, multiple therapeutic uses are attributed to butterbur. The list, compiled from the six books, includes: prevention of episodic migraine headaches; treatment of seasonal allergies; relief of joint pain; decrease of cough, bronchitis, and asthma; ease of irritations of the small intestine; treatment of gastric ulcers; and reduction of urinary tract spasms.
Unlike many of the herbs discussed in these books, butterbur has some evidence of effectiveness. A few small studies show a decrease in the frequency of migraine headaches in people taking butterbur compared to placebo. Evidence also exists, though some of it has been questioned, that butterbur is effective in treating intermittent allergic rhinitis. But there is also evidence that it is not. Studies showing benefits of butterbur for asthma exist, but most of them have been done in animals.
What about the other conditions? Several of the books state that butterbur helps treat “gastric ulcers and small intestinal irritation.” A search for the science behind those statements is revealing. In a 2001 monograph in Alternative Medicine Review (a journal that existed for sixteen years and ceased publication in 2012), it was stated that “ethanolic extracts of Petasites hybridus blocked ethanol-induced gastric damage and reduced ulcerations of the small intestine caused by indomethacin.” That statement was copied almost verbatim from the 1993 study that reported, “Alcoholic extracts of Petasites hybridus block the ethanol-induced gastric damage and reduce small intestinal ulcerations induced in rats by indomethacin” (emphasis added).
This story illustrates how misinformation can be generated, amplified, and embedded in the literature. The Alternative Medicine Review monograph omitted the important information that the one (and apparently only) butterbur gastrointestinal study was done in rats. Not only is there apparently no evidence that butterbur is beneficial in treating human gastric and small intestinal problems, there is no apparent evidence that this use has ever even been studied in humans or that anyone even ingests butterbur for these indications. Yet because several of the NGS books mention it, the reader could come away thinking that butterbur might be a good option to treat their gastric ulcer and/or small intestinal irritation.
Making a bad situation worse, there are no specific symptoms that can identify the source of abdominal pain or nausea as originating in the small intestine. How is the lay reader, for whom these books are intended, going to be able to make that judgment? The person who takes butterbur for abdominal pain, mistakenly thinking it is from their small intestine, could be delaying treatment of a serious condition, while consuming an herb that has no human evidence to support its use in any gastrointestinal disease. A search of the U.S. Library of Medicine through Pub Med turned up no studies on the use of butterbur for joint pain, cough, or urinary tract spasms.
Butterbur or not Butterbur. The most recently published Nature’s Best Remedies contains an excellent, extensive index, listing everything from abelmoschus esculentus to zucchini, but butterbur is not there. Butter, however, is—see previous bad advice.
The index directs the reader to four areas in the book where headache remedies are mentioned. Taken together, the list of remedies is long: cayenne pepper; magnesium; eliminating gluten; mint; inhaling lavender essential oil for fifteen minutes or rubbing it into the forehead, temples, and neck; aromatherapy with a blend of eucalyptus, peppermint, sandalwood, and rosemary; juicing with a combination of apple, cucumber, ginger, celery, and kale; and increasing intake of beans, whole grains, seeds, nuts, leafy greens, and dairy products. One wonders about the advice to increase dairy products, though, because on the same page in the well-written, accurate and helpful section informing about the etiology and pathology of headaches, we are advised that aged cheese is a migraine trigger.
In the one therapeutic area where there is some evidence that butterbur might provide benefit, butterbur is absent. Where is butterbur? This is a consequential question. This encyclopedic 318-page volume, published in 2019, has a long list of headache remedies but does not mention butterbur in any of the four sections that deal with headache. This omission makes one doubt both the benefit of butterbur and the value of the books.
The credibility of the NGS publications gets even worse when you look at two of the other books. Complete Guide to Natural Home Remedies mentions butterbur only as an alternative to fennel for cough. Throughout the book, there are ten other suggestions for headaches. The “bookazine” Natural Home Remedies describes six remedies for headaches, but butterbur is not among them.
So, half the books do not mention butterbur as being helpful for headache. That is stunning. No reputable medical book would leave out a proven, effective treatment for the condition under discussion. Given that butterbur is one of a small group of herbs that actually has some acceptable evidence of effectiveness, it seems inexplicable that it is not uniformly recommended for episodic migraine prevention in all the publications.
As in the hypertension example previously, the inconsistency among the books reflects a lack of scientific rigor and leaves the reader not knowing what to believe, if anything.
Safety and availability. Severe liver damage may occur from butterbur use. This is thought to be due to the presence of pyrrolizidine alkaloids (PA), which are in the plant itself and are hepatotoxic. A study from the World Health Organization’s database reported forty cases of hepatotoxicity, including two liver transplants associated with the use of Petasites formulations. One source states that the PA are also carcinogenic and cause lung toxicity and thrombosis. Liver function blood test monitoring is recommended by some authorities for people taking butterbur.
Minor side effects associated with butterbur have been reported to include belching, headache, diarrhea, fatigue, drowsiness, breathing difficulties, and allergic reactions. None of these is mentioned in any of the books. There is no known antidote for butterbur overdose.
To the NGS books’ credit, where butterbur is discussed, the reader is advised to only use products that are free of PA. But ensuring that may be difficult. A recent study analyzed twenty-one butterbur products sold in the United States for petasins (the active ingredient in butterbur) and PA. Seven products contained petasins and no PA. But seven products had toxic PA levels and six had no petasin. From this sample, it could be inferred that the purchaser buying butterbur has only a one in three chance that the product has the active ingredient in it and is safe.
Amazon.com sells over fifty different butterbur-containing products. A Google search results in twenty butterbur products. One costs $3.59; another, $57.99. Both contain sixty 75-mg capsules “standardized to at least 15% petasin.” Interestingly, the less expensive product’s label states that it is PA free, whereas the more expensive one does not. The consumer might wonder why there is such a huge price difference, especially because the labels imply the less expensive one is safer. Because these products are not regulated, it is not possible to know with confidence that what is inside the bottle is what is described on the outside.
There is some evidence that butterbur might be effective in decreasing the frequency of periodic migraine headaches, though the evidence is sparse and not strong. But there is also evidence that it may not be safe. The discussion of butterbur is inconsistent among the six books, and it is recommended for use in numerous conditions for which there is no evidence of effectiveness or safety. Buying a product labeled “butterbur” can be treacherous.
The Elephant in the Room
Butterbur has served as an excellent example of the potential benefits and known concerns that can be generalized to a wide range of herbal remedies recommended in the National Geographic Society books. These characteristics include:
- There is some evidence of benefit, though it is weak. The few clinical trials are small and of short duration.
- Robust safety and efficacy studies with subsequent regulatory approval are absent.
- Many of the recommendations for use have no evidence to support them.
- The incidence of adverse reactions is not quantified.
- Interactions with other herbal preparations and pharmaceuticals receive little attention.
- Dose-ranging studies have not been done, so the most effective, and safe, dose is unknown.
But beyond these issues demonstrated by butterbur is another major concern about herbal products, one that the NGS books ignore. The elephant in the room is that the lack of regulation of potency and purity results in products of uncertain quality. Unlike regulated pharmaceutical medicines, the products discussed in these books are subject to numerous variables that erode confidence, not only in quality and consistency but even in whether an active ingredient is present.
- Without regulation and post-production monitoring, the strength and purity of individual batches of herbal supplements is not ensured.
- Herbal potency may vary from manufacturer to manufacturer and batch to batch because of differences in the plant’s harvesting methods and time, geographical locations, climate, storage conditions, and variations in solvents, temperature, and extraction time.
- Poor quality control allows contaminants—arsenic and lead have been detected in herbal products, for example.
- Deliberate adulteration with pharmaceutical ingredients frequently occurs—sildenafil (Viagra) has often been found in male sexual enhancement products.
The results of the previously mentioned study that found one-third of the butterbur products analyzed had toxic levels of PA in them are as frightening as they are instructive. Equally concerning is that a recent analysis of an FDA database found 776 adulterated dietary supplements from 146 different companies during the years 2007–2016. That averages out to one fraudulent product discovered every five days for ten years. Though a majority of the products were for sexual enhancement or weight loss, it should raise red flags for purchasers of any “dietary supplement.” None of these issues is addressed in any substantive or comprehensive way in the six NGS books.
Multiple problems ensue when inaccurate health product information is advanced. The consumer may not receive any benefit, as the product may not do what is claimed. The product itself may directly cause harm. It may interact with other medications and herbal preparations. Delay while taking the ineffective product until proper treatment is obtained may worsen the condition or increase the likelihood of more serious harm. Money could be wasted.
Products promoted to improve health should have undergone thorough scientific and clinical evaluations that demonstrate sufficient evidence of safety and efficacy, and production and post-marketing surveillance should be regulated. The authors and publishers of books offering health advice should scrupulously ensure their messages are evidence-based and can do no harm. Unfortunately, the NGS books fall short.
The editors of the National Geographic Society should reconsider their “natural remedies” publishing enterprise. Producing books full of claims that lack evidence and don’t meet even minimum scientific standards belies the NGS’s stated “passion for science.” Some of the advice can harm. The inconsistencies among the books are troubling and weaken any argument that they are providing “information people can trust.” The National Geographic Society should not sully its reputation by promoting health practices and products not supported by credible scientific evidence.
The books reviewed:
- Guide to Medicinal Herbs (2010)—384-page book.
- Complete Guide to Natural Home Remedies (2012)—384-page book.
- Nature’s Best Remedies (2019)—318-page book.
“Bookazines” softcover, 8½ x 11 inch, yellow-bordered publications:
- Healing Remedies (2014)—112 pages
- Nature’s Best Remedies (2015, reissued 2018)—128 pages
- Natural Home Remedies (2017, reissued 2019)—112 pages
- Chugh, N.A., S. Bali, and A. Koul. 2018. Integration of botanicals in contemporary medicine: Road blocks, checkpoints and go-ahead signals. Integrative Medicine Research 7: 109–125. Excellent review article with 225 references.
- Diener, H.C., F.G. Freitag, and U. Danesch. 2018. Safety profile of a special butterbur extract from Petasites hybridus in migraine prevention with emphasis on the liver. Cephalalgia Reports 1: 1–8.
- Tachjian, A., V. Maria, and A. Jahangir. 2010. Use of herbal products and potential interactions in patients with cardiovascular diseases. Journal of the American College of Cardiology 55: 515–525. A thorough look at the potential dangers of herbal products.
- Tucker, J., T. Fischer, L. Upjohn, et al. 2018. Unapproved pharmaceutical ingredients included in dietary supplements associated with US Food and Drug Administration warnings. JAMA Network Open 1(6): e183337.
- Wells, R.E., J. Beuthin, and L. Granetzke. 2019. Complementary and integrative medicine for episodic migraine: An update of evidence from the last 3 years. Current Pain and Headache Reports 23:10.