In the interests of fairness and intellectual honesty, I’ve forced myself to read a lot of really bad books. The True Believer tells me his guru’s book is the Real Stuff. He tells me I have a closed mind and won’t look at anything outside establishment dogma, and if I only read the book and understood Dr. Quack’s evidence and arguments, I would be a True Believer too. I have tried, really I have. I’ve given the Dr. Quacks every chance to convert me, and I’ve hoped to learn something new, but I’m always disappointed. I’ve come to the point that I feel like I’m reading the same book over and over: it is always a mixture of real science, pseudoscience, and speculation, based on cherry-picked evidence and argued with the same logical fallacies.

I recently got hooked into reading another one by a correspondent who had called me an “ignorant relic” for writing a “grossly ignorant article” about alternative medicine. I suggested he read R. Barker Bausell’s book Snake Oil Science and a couple of others, which he promised to do. Then he said, “If I am willing to buy three books that you have suggested and read them and you are not willing to read what I have suggested, then that pretty much says all that needs to be said.”

I was willing, even though the very title of the book suggested that its message was incompatible with the scientific evidence as I know it: How to Prevent and Treat Cancer with Natural Medicine. The authors are big names in naturopathic and herbal medicine: Michael Murray, Tim Birdsall, Joseph Pizzorno, and Paul Riley. It’s nowhere near as bad as some of the bad books I’ve read, but it is a good example of the genre and I’ll use it to illustrate why I call them bad.

It offers “an arsenal of disease-fighting tools for prevention, treatment, and coping with side effects” (Yes, it offers tools; but do those tools work?) And it promises to “change your internal environment so cancer can’t survive.” (Wow! If it could really do that, every oncologist in the world would enthusiastically adopt these methods and the authors would be eligible for a Nobel prize.)

Its coverage of cancer risk factors and screening tests is reasonable, and it doesn’t discourage conventional cancer treatment. It recommends conventional preventive measures like exercise, weight control, and healthy diet, and points out the need for extra attention to good nutrition during cancer treatment. It doesn’t descend to the level of Andrew Weil’s promotion of “stoned thinking” and intuition as a source of knowledge. It appears to be grounded in science and its recommendations are evidence-based. The problem is that it accepts evidence of exceedingly poor quality, and it accepts evidence that has been superseded by other contradictory evidence (which it conveniently fails to acknowledge).

A trivial example, but one that illustrates their loose approach: they tell us acupuncture dates back 5000 years to The Yellow Emperor’s Classic of Internal Medicine, attributed to the emperor Huang Ti in 2697 BC. They don’t mention that modern scholars have determined that the book was written much later, probably in the second century BC. The older date enhances their claim that

TCM [Traditional Chinese Medicine] has been practiced for millennia, longer than any other medical system. There must be something valuable in it! [Logical fallacy]

They fully accept the claims of TCM. They fail to mention that the so-called acupuncture meridians have never been detected, and they speak of the mythical qi as if it were as real as blood pressure. They accept the totally unsubstantiated concept of “energy medicine.” They think there is no fundamental clash between Western medicine and TCM, that just as light can exist as particles or waves, health problems can affect both chemical balance and energy balance. [false analogy]

They state

External hydrotherapy treatments have been shown to produce profound effects on immune function. In particular, applications of hot water have been shown to boost the number and activity of natural killer cells – key white blood cells in the fight against cancer.

As a reference, they cite this study. This was a preliminary study with only 10 subjects and no controls, and the number of NK cells only increased in 5 patients. A search of PubMed yielded only one other study of hydrotherapy and immune function, this one also uncontrolled and involving only 11 subjects.

You would have to put on the strongest rose-colored glasses to interpret these two questionable studies as evidence of “profound effects.” And that is exactly what these authors do throughout the book. Their rose-colored glasses over-interpret the significance of every study that supports their bias while they filter out any contradictory information.

They state that faith and the power of prayer have been “validated by several rigorous scientific studies” showing that prayer affects everything from the mutation rate of bacteria to the size of tumors. This is simply not true. Claims for the medical efficacy of prayer have been repeatedly and thoroughly debunked. Yet these authors say,

In our opinion, given the scientific support of prayer’s beneficial effects, not praying for the best possible outcome may be the equivalent of deliberately withholding an effective drug or a surgical procedure.

They stop short of advising us which God to pray to.

For patients undergoing surgery, they say “It is very important to use gotu kola to prevent the formation of adhesions.” They say it has “demonstrated impressive clinical results in promoting wound repair.” The Natural Medicines Comprehensive Database, after reviewing all the published studies on gotu kola, concluded that it is “possibly effective” when used topically for wound healing and prevention of keloids, and “possibly safe.” I couldn’t find a shred of evidence anywhere that it can prevent the formation of adhesions internally. As far as I can tell, the authors just made that up, extrapolating from the idea of wound healing.

For cancer prevention, they recommend everyone take 17 supplemental vitamins, 14 supplemental minerals, flavonoids, daily green drinks (green tea, dehydrated barley grass, wheat grass, chlorella, spirulina), probiotics, fish oil supplements, and for extra protection against specific cancers, curcumin, quercetin, ground flaxseed oil, lycopene, etc. The evidence to support these recommendations is sketchy at best (I’m trying really hard to say this politely).

I’ll stop with these few examples. It would take a book twice as long as theirs to properly critique all their questionable statements.

This book is a strange mixture. It contains a lot of good science and good advice, but it also contains statements that are clearly false, and much of it consists of unjustified extrapolations from preclinical or preliminary studies. It unwisely makes clinical recommendations for the entire human population on the basis of a few animal or in vitro studies.

It epitomizes the difference between “evidence-based” and true science-based medicine. It is easy to find studies that serve as “evidence” for any viewpoint, but the true scientist weighs those against other contradictory studies, assesses the study design and the quality of evidence, asks if the data have been replicated elsewhere, looks at prior plausibility and compatibility with other scientific knowledge, and tries to judge what the entire body of scientific evidence means. As Ioannidis showed in his landmark article, most published studies are wrong.

The book has the appearance of science and authority and it cites lots of references. It is written to impress the general public, and I’m sure it sounds very convincing to someone who is not well versed in the subjects covered. But its defects are obvious to anyone who truly understands the scientific method. The authors have an obvious bias; they are not objective, some of the things they say are demonstrably false, and the book is not a reliable source of information or advice.

There are two kinds of science book: one aims to educate the public by explaining the current state of evidence and the consensus of the scientific community. The other has an agenda: it uses (and mis-uses) science to persuade readers to believe something that the authors believe but that the scientific community as a whole has rejected. I have learned to tell them apart at a glance. Unfortunately, the general reader hasn’t.

Caveat emptor and caveat lector.

Posted by Harriet Hall

Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren't Supposed to Fly.