Mark Hyman, a proponent of so-called “functional medicine” promoting himself over at the Huffington Post (an online news source that essentially allows dubious medical infomercials to pass as news) has posted a particularly egregious article on personalized medicine for dementia. In the article Hyman distorts the modern practice of medicine, the current state of genetic science, and the very notion of “disease.” It is, as usual, a fine piece of medical propaganda sure to confuse many a reader.

Hyman starts with some standard epidemiology of dementia – it is a common and growing disorder – but then descends quickly into distortion and pseudoscience.

Conventional Medicine Strawman.

Hyman creates what readers are likely to recognize by now as the standard straw man of conventional or science-based medicine, and then uses that caricature to create a false dichotomy with his “functional” medicine. He writes:

But first I want to explain why just naming a disease — whether it is dementia or anything else — is becoming increasingly unhelpful (unless you just want to match the drug to the disease which is the only thing doctors are trained to do).


In fact, disease and diagnosis as we know it will soon be an obsolete concept, an artifact of medical history, like bloodletting or phrenology (the art of diagnosis based on the shape of your skull, popular in the 19th century). The reason is simply this: Naming a disease does nothing to help us identify and treat the underlying causes of the disease. We must address these causes if we have any hope of helping individuals heal.

As a neurologist who treats dementia, his straw man is more than a bit offensive. Hyman does not seem qualified, if his writings and videos are any indication, to offer an opinion on medical training. Hyman would have you believe that the science-based approach is going the way of bloodletting. But what he is really indicating is that he does not understand the label of dementia, the concept of disease, or the complex relationship between science and medical practice.

What is a disease?

Hyman uses the term “dementia” quite loosely in his article, so let me explain what we actually mean by this term. Dementia is a clinical syndrome (not a disease) – it is the term applied to a condition of chronic cognitive impairment, regardless of cause.

On the other hand, Alzheimer’s disease is a specific disease – a pathophysiological entity with specific changes to the brain on biopsy and markers in the blood and spinal fluid (although at present only biopsy is useful for diagnosis).

When a patient presents with dementia (actually they present with cognitive symptoms and are diagnosed with dementia based upon history and exam, distinguishing it from other entities, like delirium, psychosis, or specific disorders like language dysfunction) the first order of business is to rule out treatable or reversible forms. This may include depression, medication side effects, nutritional deficiencies, anatomical lesions, strokes, inflammatory diseases, toxicities, and other causes. This is done by history, physical, MRI scan of the brain, EEG, and blood tests.

If an underlying treatable cause is found, it is treated. Patients may then stabilize, improve, and even be entirely cured, depending on the cause and if any permanent damage has already occurred.

If the workup for reversible causes is negative then the patient is not given the diagnosis of Alzheimer’s disease – rather they are diagnosed with an Alzheimer’s-like dementia, or a related but still irreversible cause of dementia.

It is true that simply attaching a label to a syndrome does not necessarily lead to effective treatment or even better understanding, as I have pointed out myself previously. In fact, some syndrome labels are over-used. But the same is not true of a genuine disease label – a diagnosis that carries with it a host of information about epidemiology, risk factors, underlying causes, genetic predispositions, and treatment outcomes.

Hyman hopelessly confuses these two situations, demonstrating a profound lack of understanding of how medical thinking has progressed over the last couple of centuries. Hyman demonstrates his confusion by using the term “dementia” as if it were interchangeable with “Alzheimer’s disease.” He writes:

“There is no effective known treatment for dementia.”

This statement is flawed on many levels. Some dementias are treatable, even curable, if the cause is reversible. It is true there is no cure for Alzheimer’s disease, and no disease-modifying treatment, but there are treatments. Currently available treatments for Alzheimer’s disease, however, are symptomatic only – they improve function but do not alter the course of the disease. Hyman’s sloppy language reflects his sloppy thinking, the likely result is that his readers will end up as confused as he appears to be.

Hyman’s Anecdotes

Hyman’s article goes from bad to worse – after distorting the current state of neuroscience and medical practice regarding dementia, his infomercial for his own idiosyncratic methods begins. He offers, of course, just anecdotes – two patients whom he treated and who we are told improved.

Of course, we are given no information to confirm a diagnosis. Since Hyman appears not to know the difference between dementia and Alzheimer’s disease, it is quite possible that either or both of these patients had a reversible cause of dementia, and their improvement may or may not have had anything to do with his ministrations. But they are useless as evidence for any superiority of Hyman’s approach to the science-based approach.

For example – despite the fact that Hyman would have you believe my training was restricted to pharmacotherapy,  I routinely will check patients who present with dementia for folate and vitamin B12 deficiency (this is standard practice). In addition I check homocysteine and methylmalonic acid levels, because these markers may be elevated even with low normal levels of folate and B12. If this blood work indicates a functional deficiency of either vitamin, then I supplement and monitor the blood work to see how they respond.

This is the evidence-based approach. Scientific doctors are good at asking meaningful questions and then doing research to answer them. Is the B12 and folate level enough? Turns out, the other metabolic markers may be a more sensitive indicator of a relative deficiency. Should we treat every dementia patient with folate and or B12? Turns out, there is no clinical response to routine treatment – so treatment should be targeted at those with a documented deficiency.

Gurus like Hyman, however, are not evidence-based. Rather, in my opinion, they seem to search for any tenuous evidence to support their philosophy or marketing strategy and then make huge hand-waving extrapolations from the evidence to their practice. Hyman, for example, writes:

George had another gene called MTHFR(viii) that made him require very high doses of folate to lower his blood levels of homocysteine, which is a substance very toxic to the brain.

This is part of his genetic “personalized medicine” marketing. But what I described above is true personalized medicine – using markers that have been shown to be useful in individualizing treatment – who needs folic acid and who doesn’t.

But looking at genes sounds more cutting edge – better for marketing. Hyman seems to be cherry picking the evidence. At present there is inconclusive evidence linking the MTHFR gene to an increased risk of dementia in the elderly, and a recent large study showed:

MTHFR genotypes or alleles also did not show any correlation (with dementia).

But worse, Hyman confuses the role of risk factors, markers for diagnosis, and markers for treatment. Some genotypes correlate with an increased risk of developing a disease, but are not helpful in diagnosis. Other genes are useful in diagnosis, but only some of these genes are useful in predicting outcome to specific treatments.

Now, it is true that we hope one day to usher in a phase of medicine where we use genetic testing to tailor our treatments. This is theoretically possible, and we are making progress, but we are not there yet. Just as we hope one day to cure many diseases with stem cells, but I would not pay to go overseas to a stem cell clinic today.

Hyman is misusing current research to determine treatment – but this is simply not evidence-based. It is not “functional” medicine, it is bad medicine. Science-based doctors want to know what markers actually mean – and for treatments that means they need to be tied to treatment outcomes. None of the studies Hyman references actually support the genetics-based treatment decisions he is advocating.

I would also point out that he mixes in some advice that is based on evidence, but that is already part of standard evidence-based practice (or is being incorporated in response to published evidence). For example, here is a study which concludes:

CONCLUSION: Vegetables, unsaturated fats, and a high MeDi score may be beneficial to cognitive function.

MeDi is short for a Mediterranean diet. The evidences shows decreased risk and better long term outcomes for patients who eat plenty of vegetables, have low saturated fats, and generally eat a Mediterranean diet (which has lots of vegetables and low saturated fats). This is a generally healthful diet in many ways – and we don’t need to test your genes to recommend it.

Hyman also recommends exercise – and there is evidence that exercise reduces risk and improves outcome in vascular dementia and other dementias. So that is also part of conventional treatment. I wonder who Hyman thinks is doing all these studies on diet and exercise, since he believes physician training only includes matching drugs to diseases.


Science-based medicine includes many modalities of intervention, including diet, targeted supplementation, exercise, risk modification, symptomatic treatment, and where possible disease modification. The research on any particular medical topic, like dementia, is very deep and nuanced and requires understanding of the complex relationship between syndrome, disorders and diseases, the relationship between biomarkers and pathophysiology, the differences among markers for risk, diagnosis, and treatment outcomes, and the types of evidence that are useful in determining which treatments work and are appropriate for specific patients.

Mark Hyman, in advocating for his “functional” medicine, appears to understand none of this. Instead he whitewashes over all this complexity and would have his readers believe that science-based practitioners take a simplistic knee-jerk pharmacological approach to all patients. The evidence clearly puts the lie to this caricature.

Meanwhile he himself takes what appears to be an overly simplistic approach – extrapolating tenuously and inappropriately from various different kinds of evidence to ultimate treatment decisions. Specifically in this essay he abuses preliminary evidence on the relationship between various genetic markers and disease risk factors to give the illusion of personalized medicine – prematurely declaring the death of the indispensable notion of “disease.”

He seems to have failed to notice that the very evidence he is citing is often closely tied to, or even dependent upon, the concept of a pathophysiological disease.

He further borrows from legitimate science in order to argue for the inadequacy of the scientific tradition that created the evidence in the first place. We know about the legitimate benefits of exercise and a healthful diet because of science-based medicine – not the slick marketing of self-promoting gurus.

Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the president and co-founder of the New England Skeptical Society, the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also contributes every Sunday to The Rogues Gallery, the official blog of the SGU.