I first wrote about “earthing”, also called “grounding”, about a decade ago. Briefly, the idea of earthing is that electrically grounding oneself has a long list of health benefits. I found these claims dubious a decade ago, but I also like to follow up on the research into topics I previously tackled. One of the best ways to judge the validity and potential of a scientific area of research is to see how it evolves over time. Real sciences tend to make tangible progress, while pseudosciences tend to chase their tail.
In medicine, which is an applied science, there are very concrete differences between the real and the fake, and it is only after we see how the medical research progresses that we can confidently say which approaches are useful and which are not. What we like to see as the medical literature on a topic evolves is a persistent statistically significant and clinically relevant effect size that persists as studies become more rigorous and are replicated. What we typically see with dubious treatments is a persistent failure to replicate, studies generally never progress to more rigorous methods, and an inverse relationship between study rigor and positive outcomes.
As I wrote, again about a decade ago, we know from history that there are reliable indicators of when a medical hypothesis is legitimate. Generally we like to see four simultaneous features: methodological rigor, significantly positive effects, reasonable clinical effect (and signal to noise ratio), and replication. Just three are not enough, because you can manufacture positive-seeming results if you can ignore one or more of these criteria.
There is also the issue of medical plausibility. This is, admittedly, a secondary concern with conventional hypotheses in terms of determining clinical efficacy. But that “conventional hypotheses” is a critical caveat. The more a hypothesis seems to violate the laws of physics, the more prominent plausibility is as an issue. For claims that are implausible but not impossible, we could still accept a real effect if the clinical evidence were a home run. Here plausibility informs us where we should set the threshold for tentative acceptance. Moderate clinical evidence might be enough, for now, for a highly plausibility, even expected, outcome. But if everything we currently know says that an intervention should not work, we should demand a higher threshold of clinical evidence before superseding prior knowledge.
Where does earthing fit into this scheme? When I wrote about it in 2012 I felt it was clearly on the pseudoscience side of the equation. Let’s start with the plausibility. The claim is that in our natural state we were more connected to the Earth, walking barefoot on the ground. This allowed for electrons to flow to and from our bodies, creating an electrical homeostasis that was optimal for health. In our modern world, however, we live inside buildings and wear rubber soled shoes. This isolates us electrically from the Earth causes us to be out of electrical homeostasis. In short, this is utter nonsense.
The reason electrical devices are grounded is to give electrons somewhere to go, in case of some source of overload (like lightening) or just to prevent them from building up. Even a small backup of current can create electrical noise in a sensitive system. And of course the amount of electricity we are talking about is massive compared to what our bodies experience. Further, even with rubber soles, we are far from electrically isolated. We easily share electrons with everything we touch. When you have a brief build up of electrical charge you usually find our right away, because you get a static electric shock the next time you touch something conductive (which, of course, neutralizes the charge). Just from the perspective of basic physics, earthing makes no sense. It sounds like the nonsense someone with only a partial understanding of the underlying science cooked up.
The intervention is mostly to spend time walking on the ground in bare feet. But of course, there are also dubious devices, such as grounding mats, that you can sit, stand, or sleep on, and that are in turn grounded to the Earth. There is no evidence that these devices do anything. There is also no research establishing the basic underlying claim – that there is an electrical homeostasis that has any effect on how the body functions, and that this is affected by grounding.
The medical part of the plausibility equation is also highly dubious. According to one researcher:
Because the continuous semiconducting fabric of the body reaches into every part of the body, including the interiors of all cells and their nuclei, mobile electrons in the grounded or earthed person are thought to be capable of rapidly neutralizing ROS produced by oxidative metabolism taking place in every cell and tissue.
The “antioxidant” gambit rears its head again. I have covered why antioxidants are not a panacea extensively here already. In short, oxidative stress is part of a complex homeostatic system in the body, and we already possess powerful antioxidants that don’t need the help of whatever dubious treatment is being proposed. I would give this one an overall plausibility of close to zero.
What about the clinical evidence – how has that evolved in the last decade? It has progressed like a typical pseudoscience, following the path of other dubious claims like homeopathy and acupuncture. First, it leans heavily on pre-clinical studies that fit the pattern – “look, stuff is happening”.
In previous studies, grounding revealed anti-inflammatory effect, immunity enhancement, anticoagulation, and rising blood oxygenation.
I always love it when a treatment is simultaneously “anti-inflammatory” and “immunity enhancing”. These are almost necessarily contradictory. It shows that no matter what happens it can be interpreted in a positive way. These pre-clinical studies look at markers, like cells or biochemicals, to determine effect. This kind of research is rife with difficulty and dubious results (not to say it can’t be useful when properly done). It also has a very loose connection to later clinical studies – in other words, not very predictive at all. So, take a look at a bunch of immune markers, if any go up that is “boosting immunity”, if any go down that is “anti-inflammatory”.
The last ten years of published clinical studies have been entirely unimpressive. Studies generally have small numbers of participants, focus on subjective outcomes (the usual suspects of pain, “well-being”, and stress), and are poorly controlled. Never do we see all features of rigor simultaneously.
What they do (very much like the acupuncture literature) is allow proponents to claim that there is scientific, even “double blind”, evidence to support their claims. But each individual study does not survive scrutiny. In this study, for example, they used a “wedge” design in which all subjects received the same pattern of treatment (placebo on some days and treatment on others) without variation. I am not sure how this can be “double” blind when every participant had the same pattern. They didn’t even mix it up to make sure it wasn’t an artifact of timing (reporting more of an effect with more treatments). Also, if you look at the data, the results are all over the place, with many outcomes not statistically significant. They are just cherry picking apparently positive outcomes while not properly adjusting the statistics for multiple outcomes. And the number of participants was 16, so we would expect lots of quirky results.
Another pattern that is apparent is that most of the research is published in “alternative medicine” journals, predatory journals, or other low impact journals. This allows for the creation of the illusion of scientific support without ever crossing the threshold of scientific legitimacy.
Earthing is another example of exactly what is wrong with biomedical publishing. It favors the publication of large numbers of low quality studies, with plenty of opportunities for proponents of dubious medical treatments and beliefs to get into the peer-reviewed literature. For the uninitiated this creates the appearance of legitimacy, even for highly implausible treatments.