It’s likely you know someone who has bought into the notion that nutrition is everything, the source of all health and the cause of all illness. Nutrition is very important, to be sure, but it is only one of many possible causes of disease, and if you live in a Western industrialized nation you probably have adequate nutrition. The notion, however, that food can heal is powerfully alluring, and it makes great headlines. The result is that people who read the headlines for the latest food to avoid, or the latest ingredient that will make them live longer or stave off disease, seem to have an association for everything. Eating around them is to be constantly told that food X is good for you and will prevent Y, or that some other food should be avoided because it causes Z.
Red peppers will help prevent cancer and help you lose weight. Garlic will help prevent heart disease and aids in iron metabolism. Cayenne pepper prevents strokes. Peaches prevent heart disease and cancer. In fact- think of any food at random and type “random food health benefits” into Google and chances are you will be rewarded with a list of the amazing health benefits of whatever food you wish.
My usual response when offered such advice is – you know, food is healthy for you. I recommend you eat food every day. Food is full of nutrition, essential vitamins and minerals, and will give you energy. If you don’t eat food, your health with dramatically suffer. But don’t eat too much food – that’s not healthful.
One of the tactics of snake-oil salesmen is to fearmonger about mainstream medical practices so as to scare potential customers into their clutches. A common target of such fearmongering is vaccines. Vaccine are an easy target – they are generally required by the government to some degree, and involve sticking small children with needles and injecting them with a cocktail that parents often don’t understand in detail.
While vaccines are of clear benefit, no one argues that they are risk free. There are rare serious complications. For this reason the US established the NVIC – National Vaccine Injury Compensation program. This is funded by a small tax on each vaccine, and is designed to compensate families of children who have a possible reaction to vaccines, bypassing the slow and costly regular court system. The NVIC works well.
The goal of the NVIC is not to determine scientifically if there is a link between a particular vaccine and a particular side effect. That is determined by the scientific community. Rather, the NVIC’s charge is to determine if “compensation is appropriate” in specific cases. They also give the benefit of the doubt to the families.
Science-based medicine is partly an exercise in detailed navel gazing – we are examining the use of science in the practice of medicine. As we use scientific evidence to determine which treatments work, we also have to examine the relationship between science and practice, and the strengths and weaknesses of the current methods for funding, conducting, reviewing, publishing, and implementing scientific research – a meta-scientific examination.
There have been several recent publications that do just that – look at the clinical literature to see how it is working and how it relates to practice.
Dr. Vinay Prasad led a team of researchers through the pages of the New England Journal of Medicine hunting for medical reversals – studies that show that current medical practice is ineffective. Their results were published recently in the Mayo Clinic Proceedings:
Dr. Prasad’s major conclusion concerns the 363 articles that test current medical practice — things doctors are doing today. His group determined that 146 (40.2%) found these practices to be ineffective, or medical reversals. Another 138 (38%) reaffirmed the value of current practice, and 79 (21.8%) were inconclusive — unable to render a firm verdict regarding the practice.
Prasad also found that 27% of published studies looked at existing treatments while 73% studied new treatments.
I did not coordinate my topic for today with Harriet’s excellent review yesterday of Satel and Lilienfeld’s excellent book; the timing is just fortuitous. Harriet discussed popular abuses of neuroscience, which often amount to an oversimplification and hyperreductionism of a complex area of study. I was recently asked to comment on a claim that I feel falls squarely into this realm – so-called conscious discipline.
From the conscious discipline website:
It surpasses behavioral approaches that teach specific behaviors, and offers a neurodevelopmental model of the brain…
The Conscious Discipline Brain State Model becomes a frame for us to understand the internal brain-body states that are most likely to produce certain behaviors in children and in ourselves. With this awareness, we learn to consciously manage our own thoughts and emotions so we can help children learn to do the same.
They even offer a helpful picture of the brain to illustrate their model (above).
A recently published epidemiological study in JAMA Pediatrics looked at the association between induction and enhancement of labor and the risk of autism. The researchers found a positive association, especially with males. The study has been variously reported in the popular press with causal interpretations not justified by the data.
The study itself is very robust – the authors looked at 625,042 live births, including 5,500 children with a diagnosis of autism. They found:
Compared with children born to mothers who received neither labor induction nor augmentation, children born to mothers who were induced and augmented, induced only, or augmented only experienced increased odds of autism after controlling for potential confounders related to socioeconomic status, maternal health, pregnancy-related events and conditions, and birth year. The observed associations between labor induction/augmentation were particularly pronounced in male children.
Although this is a large study, it is one study, and so the correlation needs to be independently confirmed. But if we assume the correlation is accurate, the next question is – what is the arrow of causation? Observational studies can only indicate an association. By themselves they cannot prove causation, although multiple observational studies may be able to triangulate to the most likely causal interpretation. (more…)
Those who cannot remember the past are condemned to repeat it.
– George Santayana
Science-based medicine is more than a set of methods or certain philosophy of medicine – it is an entire approach to what should be the core questions for any interventionist profession: is it real and does it work?
These are often deceptively difficult questions to answer. Fortunately we have at least a century of experience applying systematic methods to answering these questions within the context of medicine. This is a wealth of history from which to learn, full of cautionary tales and enlightening examples.
However, as Winston Churchill lamented, we tend to forget the lessons of the past leading to, “…the most thoughtless of ages. Every day headlines and short views.”
Part of the mission of science-based medicine (and skepticism in general) is to remember the lessons of the past as they relate to science and pseudoscience, and to constantly remind the public and our colleagues of these lessons.
Yoga is an increasingly popular form of exercise in the US. According to Yoga Journal more than 20 million Americans use yoga as their form of exercise. As a form of exercise yoga is fairly straightforward, involving stretching and holding poses that strengthen muscles. It also carries the generic benefits of any exercise in terms of calorie-burning and cardiovascular health.
Yoga, however, is more than exercise – it also comes with a “spiritual” angle. The term itself refers to a number of practices originating in ancient India meant to strength mind, body, and spirit. For this reason it has become a popular target for marketing the latest health pseudoscience. You will be hard pressed, in fact, to find a yoga class that does not incorporate some degree of outright woo, the only question really is not if, but how much. This is unfortunate because yoga may be an effective alternative for low-impact exercise.
There is some evidence that yoga, for example, is effective in relieving low back pain, although it may not be more effective than usual care. There is a lack of quality studies comparing yoga to other forms of exercise, and so we may just be seeing the generic benefits of exercise. Still, if the classes are fun and they keep people motivated to continue their exercise regimen, that is useful.
Yoga, therefore, fits into a more general phenomenon of marketing a specific intervention as if it has specific benefits, when in fact it only has generic benefits. For example, there are many studies showing that transcendental meditation is effective for lowering blood pressure. However, studies generally compare TM to no intervention, not to other forms of relaxation. The parsimonious interpretation is that TM confers the generic benefits of relaxation, but there is no evidence to suggest it confers any specific benefits.
Mercury in unequivocally a neurotoxin. It is especially damaging to the developing brain. But it’s the dose that makes the toxin, and so a low enough exposure even to something known to be potentially harmful may not be. Further, the body has mechanisms for dealing with toxins, and toxins in the body may not be reaching the cells they can potentially damage in significant amounts. Therefore if we want to know if a potential toxin is actually causing any harm to people we need to do some type of epidemiological study – correlating exposure to possible adverse outcomes. All the studies in petri dishes and with cell cultures just won’t answer the question of harm.
The question of whether or not mercury in vaccines has caused neurological harm, specifically autism, has been largely answered. Numerous studies have shown no association between the amount of mercury exposure from vaccines and the risk of developing autism. A separate mercury-related question, however, is whether or not there is any risk of harm from mercury exposure from seafood. Mercury is methylated by bacteria into methymercury, and through them gets into the food chain in the oceans. Fish that eat other fish then concentrate the mercury in their tissues, and so predatory fish and sea mammals tend to have high concentrations of methymercury.
This has led to some precautionary recommendations, including that pregnant women should not eat tuna or other fish with high mercury levels. This makes sense, but what is the actual risk? The precautionary principle can also cut both ways. Fish contain many high-quality nutrients important for a developing brain, such as polyunsaturated fatty acids. Removing this food source from the diet of pregnant women may have unintended negative consequences.
The internet is a fabulous resource of information. It is one of those technological innovations for which you soon can no longer imagine how you lived without it. I certainly cannot imagine a project like science-based medicine prior to the web.
The web, however, is also a tremendous source of misinformation, opinion, and ideology. Also the volume of information, good and bad, can be overwhelming. We therefore are frequently asked the meta-question of how we conduct our research into specific topics, or how can the average layperson do their own research online.
Efficiently and effectively researching a complex topic is complex. It is a skill that needs to be developed, and it is especially difficult without having detailed knowledge of the specific topic ahead of time. Therefore there is no simple answer to this question, but I can offer some tips.
There are two main resources I use when searching a topic, Google and PubMed. They each have their strengths and weaknesses. For the average user, Google (or whichever general search engine you prefer) is likely going to be your first stop.
In the last decade or so there has been increasing research into non-invasive brain stimulation techniques for a variety of conditions. These include transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), random noise stimulation (tRNS), and transcranial magnetic stimulation (TMS). These techniques alter the excitability of neurons in the brain, seem to have an effect on plasticity (the ability to form new connections), and can modulate the activity of brain networks.
Overall the current research is preliminary but encouraging. Many of the details of exactly how to apply this new technology, however, are still being worked out. One recent review summarizes this complexity:
tDCS can be used to manipulate brain excitability via membrane polarisation: cathodal stimulation hyperpolarises, while anodal stimulation depolarises the resting membrane potential, whereby the induced after-effects depend on polarity, duration and intensity of the stimulation. A variety of other parameters influence tDCS effects; co-application of neuropharmacologically active drugs may most impressively prolong or even reverse stimulation effects. Transcranial alternating stimulation (tACS) and random noise stimulation (tRNS) are used to interfere with ongoing neuronal oscillations and also finally produce neuroplastic effects if applied with appropriate parameters.