When you pick up a bottle of supplements, should you trust what the label says? While there is the perception that supplements are effective and inherently safe, there are good reasons to be skeptical. Few supplements are backed by good evidence that show they work as claimed. The risks of supplements are often not well understood. And importantly, the entire process of manufacturing, distributing, and marketing supplements is subject to a completely different set of rules than for drugs. These products may sit on pharmacy shelves, side-by-side with bottles of Tylenol, but they are held to significantly lower safety and efficacy standards. So while the number of products for sale has grown dramatically, so has the challenge to identify supplements that are truly safe and effective. (more…)
If there’s a characteristic that’s common among proponents of alternative medicine, it’s tenacity. The willingness to stick with an idea, no matter the evidence, must give one a certain clarity. The naturalistic fallacy is often the foundation. Natural is good, synthetic is bad, no matter the evidence. In some cases, in spite of the evidence. How one deals with contradictory evidence is an effective tool to differentiate between medicine and alternative medicine – given sufficient convincing evidence, medicine changes its practices. The same can’t be said for alternative medicine, where few treatments are ever discarded. Otherwise practices like homeopathy, acupuncture, reiki, and chiropractic would have disappeared long ago. It’s also why disproven products continue to have occasional resurgences in interest. Cranberry is one. It has been touted as a treatment and a preventative for urinary tract infections for years. And it doesn’t seem to work – not well, and not reliably, if you look at all the trials. And that’s being generous, considering the poor quality of the evidence with its inherent biases. I know a dead parrot when I see one. Yet its advocates, mainly manufacturers (is there a Big Cran?) keep insisting it’s alive, supported by the occasional positive report that appears. With a new systematic review and meta-analysis that declares it’s effective, it’s time to update our review. (more…)
One of the recurring topics here at SBM is the idea of the placebo: What it is, what it isn’t, and how it complicates our evaluation of the scientific evidence. One my earliest lessons after I started following this blog (I was a reader long before I was a writer) was that I didn’t understand placebos well enough to even describe them correctly. Importantly, there is no single “placebo effect”. They are “placebo effects”, a range of variables that can include natural variation in the condition being studied, psychological factors and subjective effects reported by patients, as well as observer bias by researchers studying a condition. All of these, when evaluated in clinical trials, produce non-specific background noise that needs to be removed from the analysis. Consequently, we compare between the active treatment and the placebo to determine if there are an incremental benefits, to which we apply statistical tests to determine the likelihood that the differences between the intervention and the placebo groups are real. Removed from the observational nature of the clinical trial, we can’t expect the observed “placebo effects” to persist, as they’re partially a consequence of the trial itself. A more detailed review of placebos is a post in and of itself, so I’ll refer you to resources that describe why placebo effects are plural, that placebo effects are subjective rather than objective and there is no persuasive evidence to suggest that placebo effects offer any health benefits. What’s most important is the understanding that placebo effects are a measurement artifact, not a therapeutic effect.
Placebo effects are regular topics within in SBM posts because an understanding of placebo effects is essential to evaluating the evidence supporting (so-called) complementary and alternative medicine, or CAM. As better quality research increasingly confirms that the effects from CAM are largely, if not completely, attributable to placebo effects, we’ve seen the promoters of CAM shifting tactics. No longer able to honestly claim that CAM has therapeutic effects, “treatments” such as acupuncture or homeopathy are increasingly promoted as strategies that”harness the power of placebo” without all the pesky costs or side effects of real medical interventions. But this is simply special pleading from purveyors and promoters. Unable to wish away the well-conducted trials that show them to be indistinguishable from placebos, they instead are spinning placebo effects as meaningful and worthy of pursuit – ideally with your favourite CAM therapy. Again, I’ll refer you to posts by David Gorski and Steven Novella who offer a more detailed description of how negative results can be spun to look positive. Because CAM’s effects are indistinguishable from placebo, we should not invest time and resources into pursuing them – we should instead focus on finding treatments that are demonstrably superior to placebo.
But what if physicians are already using placebos widely in practice? Setting aside the ethical issues for now, widespread placebo usage might suggest that physicians believe that placebos are effective treatments. And that’s the impression you may have had if you skimmed the medical headlines last week:
If science-based medicine reflects the application of the best evidence, then we should expect practices to change when new data emerges. In the long run that’s generally true, and the progressive gains we’ve seen in the management of disease reflect this. But in the short run, change can be maddeningly slow, and there are many areas of medicine where we could be doing a better job of applying what we already know to improve outcomes and reduce harms. One area where this is obvious is drug treatments, which can provide remarkable benefits but are also sources of significant harms.
Somewhat problematically, the real world is often the setting where the full extent of harms from treatments are identified. Bringing new drugs to market means tradeoffs: Do you demand larger and longer clinical trials to get as much information as possible about a drug before it’s sold? Or do you approve based on more preliminary, potentially weaker evidence, to meet (potentially) important patient need? There is no set formula or right answer to this questions – it’s ultimately a value judgement exercised by regulators like the FDA, who decide which drugs are allowed for sale (the benefits are assumed, overall, to exceed the harms) or removed for sale (when the opposite is felt to be the case).
Why take a drug, herb or any other supplement? It’s usually because we believe the substance will do something desirable, and that we’re doing more good than harm. To be truly rational we’d carefully evaluate the expected risks and benefits, estimate the overall odds of a good outcome, and then make a decision that would weigh these factors against any costs (if relevant) to make a conclusion about value for money. But having the best available information at the time we make a decision can still mean decisions turn out to be bad ones: It can be that all relevant data isn’t made available, or it can be that new, unexpected information emerges later to change our evaluation. (Donald Rumsfeld might call them “known unknowns.”)
As unknowns become knowns, risk and benefit perspectives change. Clinical trials give a hint, but don’t tell the full safety and efficacy story. Over time, and with wider use, the true risk-benefit perspective becomes more clear, especially when large databases can be used to study effects in large populations. Epidemiology can be a powerful tool for finding unexpected consequences of treatments. But epidemiologic studies can also frustrate because they rarely determine causal relationships. That’s why I’ve been following the evolving evidence about calcium supplements with interest. Calcium supplements are taken by almost 1 in 5 women, second only to multivitamins as the most popular supplement. When you look at all supplements that contain calcium, a remarkable 43% of the (U.S.) population consumes a supplement with calcium as an ingredient. As a single-ingredient supplement, calcium is almost always taken for bone health, based on continued public health messages that our dietary intake is likely insufficient, putting women (rarely men) at risk of osteoporosis and subsequent fractures. This messaging is backed by a number of studies that have concluded that calcium supplements can reduce bone loss and the risk of fractures. Calcium has an impressive health halo, and supplement marketers and pharmaceutical companies have responded. There are pills, liquids, and even tasty chewy caramel squares embedded with calcium. It’s also fortified in foods like orange juice. Supplements are often taken as “insurance” against perceived or real dietary shortfalls, and it’s easy and convenient to take a calcium supplement daily, often driven by the perception that more is better. Few may think that there is any risk to calcium supplements. But there are now multiple safety signals that these products do have risks. And that’s cause for concern. (more…)
If you’re a regular reader of this blog, I’ll bet you’re not a regular consumer of vitamins or supplements. I’m in that group. Aside from sporadic vitamin D in winter, I don’t take any vitamins or supplements routinely, nor do I give any to my children. Your reasons may be close to mine: There is little to no evidence suggesting that dietary deficiencies are widespread, nor is there good evidence to suggest that vitamin supplements are beneficial in the absence of deficiency. I don’t have any need for an other supplements, nor am I confident in the scientific evidence for many of them.This position of “no supplements” is a cautious and conservative one, but is based on a consideration of the scientific evidence. I view decisions about healthcare as evaluations of risk and benefit, and then cost if necessary. Given supplementation (with some exceptions) has no demonstrable benefits and, in some cases, a little risk, the odds favour not supplementing in most cases. Add in costs, and it’s even less attractive as a routine health strategy.
Yet a decision not to take vitamins or supplements regularly is becoming a minority position. Supplement use has grown over the past 40 years among Americans, with the National Health and Nutrition Examination Survey (NHANES) showing steadily increasing utilization among younger and older adults:
Like many of you I’m interested in the science of good nutrition. In general, I’ve come to be pretty skeptical of the nutritional literature, as so many studies seem to follow the same trajectory that we see with drug studies: Trivial changes in non-relevant outcomes, a failure to consider the results in the context of the accumulated scientific evidence and often, significant conflicts of interest. What’s worse, “real world” nutritional studies aren’t blinded and they’re rarely prospective. So we’re left to dig through observational studies and try to sort out correlation from causation. It’s little wonder that so many consumers are confused about the basics of healthy eating. Many believe that vitamins supplements are both beneficial and routinely necessary (they are not) and that the latest “superfood” is all that’s standing between themselves and immortality. But nutritional science is important, and I’m always pleased when patients initiate discussions about weight loss, or just improving their dietary habits. After all, obesity is a significant risk factor for an array of chronic illnesses. Improving our dietary patterns should pay off with improved health. A regular challenge I face is that my patient that has already decided to use a highly restrictive weight loss plan in order to achieve a specific weight loss goal. I always caution them to take a long-term view. Weight loss is easy. Maintaining that loss is the challenge. Most “diets” fail. So I’m critical of useless interventions (like food intolerance blood tests) or faddy diets (like going gluten-free) with the hope of easy weight loss. At its core, weight loss and weight maintenance comes down to caloric balance. Permanent weight loss requires permanent dietary changes, and how we “spend” our calories matters.
Over the past few months I’ve seen a few friends and colleagues announce that they’ve decided to transform their diet, lose weight, and “eat clean”. When I asked what “clean” food was, no-one seems to have a consistent answer. The most common response was that “eating clean” meant cutting out processed foods. But to others, eating clean meant avoiding meat, anything with GMOs, wheat, and sometimes milk. It seemed to mean something different to everyone. It reminds me a bit of Humpty Dumpty in Through the Looking Glass:
When I use a word,’ Humpty Dumpty said, in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’
Is “eating clean” just a faddish buzzword? There are a number of personalities competing in the “eating clean” dietary space. The pioneer seems to be Tosca Reno, who has the Eat-Clean Diet and about a dozen related books based on the same idea. But she’s not alone, as there are several other books with related names, including Terry Walters with her “Clean Food” books. Success breeds competition, it seems. Given Reno’s book appears to be the most popular, I’ll take her plan as the template. She outlines the principles of how she defines eating clean in her 2007 book. I’ve added my comments after each principle. (more…)
If there is an antithesis to the principles of science-based medicine, it’s probably the Dr. Oz show. In this daytime television parallel universe, anecdotes are evidence. There are no incremental advances in knowledge — only medical miracles. And every episode neatly offers up three or four takeaway health nuggets that, more often than not, seem to leave the audience more ill-informed about health and medicine than they were 30 minutes earlier.
After I completed my post on Dr. Oz’s prolonged embrace of the “miracle” that is green coffee bean extract, a number of readers brought me up to speed. Green coffee beans are yesterday’s miracle. The new weight loss miracle for 2013 is red palm oil. This constant drive for miracles must keep the producers in a perpetual panic. They need at least five miracles per week. Having now watched a few episodes, I’m reminded of the classic “That Mitchell and Webb Look” skit where two nutritionists pick a new superfood. It could be just a matter of time until we see white veal profiled as a superfood in a future Dr. Oz episode.
If there is a common characteristic of complementary and alternative medicine (CAM) proponents who believe themselves to be scientific (and I include Dr. Oz in this group), it is that they extrapolate from weak clinical evidence to grandiose claims by cherry picking the most supportive strands of evidence to give the impression of being evidence-based. They have the belief, and then they look for the supporting evidence to bolster the claim. In short, to paraphrase a quote attributed to Hahns Kuhn, they use scientific evidence like a drunkard uses a light post: for support, not for illumination. As I noted with green coffee bean extract, Dr. Oz extrapolated from ambiguous, preliminary data to recommendations to consume green coffee bean extract as a weight loss strategy. Frankly, the evidence isn’t there, so I didn’t have high expectations with the latest miracle. All I knew going in about palm oil is that it’s used in most industrial food production and the demand for it is linked to massive destruction of tropical rainforests. But who doesn’t want longevity? So I sat down and watched another episode.
“One of the most important discoveries I believe we’ve made that will help you burn fat – green coffee bean extract” – Dr. Oz, September 10, 2012, Episode “The Fat Burner that Works”
Dr. Mehmet Oz may be biggest purveyor of health pseudoscience on television today. How he came to earn this title is a bit baffling, if you look at his history. Oz is a bona fide heart surgeon, (still operating 100 times per year), an academic, and a research scientist, with 300+ or 400+ (depending on the source) publications to his name. It’s an impressive CV, even before the television fame. He gained widespread recognition as the resident “health expert” on Oprah, and went on to launch his own show in 2009. Today “The Dr. Oz Show” is a worldwide hit, with distribution in 118 countries, a massive pulpit from which he offers daily health advice to over 3 million viewers in the USA alone. For proof of his power to motivate, just look at the “Transformation Nation Million Dollar You” program he launched in 2011, enrolling an amazing 1.25 million participants. Regrettably, what Oz chooses to do with this platform is often disappointing. While he can offer some sensible, pragmatic health advice, his show’s content seems more focused on TV ratings than medical accuracy, and it’s a regular venue for questionable health advice (his own, or provided by guests) and poorly substantiated “quick fixes” for health issues. (And I won’t even touch Oz’s guests like psychic mediums.) One need only look at the number of times the term “miracle” is used on the show as a marker of the undeserved hyperbole. Just this week, Julia Belluz and Stephen J Hoffman, writing in Slate, itemized some of the dubious advice that Oz has offered on his show, with a reality check against what the scientific evidence says. It’s not pretty. (more…)
If there were an icon of Science-Based Medicine, I think it should be Sisyphus: pushing a boulder uphill, only to watch it roll down again. Forever. Blogging about pseudoscience in medicine can feel that way at times. There is no end to the variations of nonsense, most health professionals are indifferent at best, and sometimes I wonder if blogging is just preaching to the converted. Compared to the media presence and web traffic of those that promote pseudoscence, I do wonder what to make of SBM. Does it have a bigger impact. Occasionally something comes along to give you some hope that the key concepts of SBM are having some resonance.
To effect meaningful change, we need to teach the concepts of SBM – the process is the product, not the topics we blog about. This all came to mind as I was reading an open letter from TED organizers. TED talks are now iconic, but if you’re unfamiliar with them, the conferences started as a means of colliding speakers in the technology, entertainment and design fields to talk about big ideas. With a slogan of “ideas worth spreading,” perhaps it’s not surprising that TED talks can be provocative: that’s the point. TED talks are posted online and their success is remarkable: some talks get hundreds of thousands of views. The TED template has become so popular that it spawned TEDx, independent but licensed events that bring TED-like talks to smaller cities and venues. I’ve seen several TED talks and while many are compelling speakers, it’s clear the content is not always grounded in evidence. For all the talks by science advocates like Ben Goldacre, or James Randi, there’s the consciousnessbabble from Deepak Chopra. I’ve never seen TEDx presentations, but recently there’s been some very public criticism of its speaker standards. Anyone, it seems, can be a TEDx speaker including anti-GMO crusaders and naturopaths. Stung by recent criticism that the TED brand is losing credibility with its questionable presenters, TED HQ recently advised TEDx organizers to stop featuring pseudosicence:
It is your job, before any speaker is booked, to check them out, and to reject bad science, pseudoscience and health hoaxes.