Terra Sigillata

Humility among scientists

i-3923a2203bb61b4cda0f95ca926d56c2-OpenLab2006.pngYesterday, Revere (Effect Measure) threw down the gauntlet challenging those critical of alternative medicine to examine work done at the University of Nebraska Medical Center in 2000 on the medicinal properties of chicken soup.

The news release cites work that a chicken/vegetable soup, but not simple chicken broth, inhibits in vitro neutrophil migration, or chemotaxis. Inhibiting the migration of this class of white blood cells might reduce the nasopharyngeal symptoms of the common cold, thereby providing some evidence that grandma’s chicken soup might very well help one feel better during cold and flu season.

Since these were in vitro or Petri dish experiments, my first question was whether the bioactive components of the soup get into the blood or mucosal tissue at the concentrations required to have such effects against isolated neutrophils. However, the bioactive component(s) were not identified in this work. Revere asks whether this study might be enough to move chicken soup out of the category of alternative medicine into something more believable.

In a larger sense, what Revere seems to have intended by this post was to ask whether we scientists have the humility to recognize that we may not always apply the same rules for scientific rigor to our own respective fields that we expect from examinations of the more conceptually implausible forms of alternative medicine.

Perhaps even more broadly, he asks us to examine our own biases in the science/pseudoscience demarcation. This broader discussion is better handled by the resident science philosophers, such as has been done by Prof Janet Stemwedel at Adventures in Ethics and Science:

Revere stirs the pot (of chicken soup) to ask why alternative therapies are presumptively regarded as pseudo-science. The reflexive response of the quackbusters has been that alternative therapies fall on the wrong side of some bright line that divides what is scientific from what is not — the line of demarcation that (scientists seem to assume) Karl Popper pointed out years ago, and that keeps the borders of science secure.

My professional time is spent studying the scientific aspects of herbal medicine, an area that is often placed over that line of alternative medicine or “woo” even by some of my colleagues. But upon closer examination, it is quite easy for me to equivocally discuss alternative and conventional medicine because 25% of prescription drugs can trace their origins to natural sources, including plants, bacteria, fungi, marine creatures, etc. In fact, some of our greatest advances in antibiotics, cancer, and pain therapeutics have been the direct result of natural products.

Where I make a distinction in my field is the difference between saying an herb works, say, as a hypolipidemic because it is “God-given” or inherently safe because it is natural vs. the same herb being represented as a source of one or more chemicals that acts as an enzyme inhibitor in pathways that control cholesterol or triglyceride metabolism. The former is a belief that does not provide a chance for testing a hypothesis; the latter, on the other hand, is amenable to investigation.

The basis for generating a hypothesis to test whether an alternative remedy has biological efficacy must have some scientific basis that is sound. I’ve heard herbalists tell me that “whole herbs” are superior to purified compounds because of synergy among components or because one herbal component blocks a side effect of an active component. These are both reasonable scenarios, but there is a great paucity of evidence in the literature to support such suppositions. (One good example of true synergy in a medicinal herb can be found in this PDF of a PNAS article from Frank Stermitz’s group.)

However, if an herbalist tells me that a whole herb works better than a pure compounds because the herb is “energized” or contains a “life force” that is extracted away by laboratory purification, I call bullshit unless there is a method to quantify these forces and demonstrate their causality with biological activity.

Back to Revere’s original query, I try to write with a degree of humility that we may not know all there is about modalities espoused by alternative practitioners – I would not put chicken soup in this camp because its purported mechanism of action is conceivable. But, again, I believe Revere is concerned more broadly about scientific humility (as evidenced by another recent post on the preconceptions at the time on the origin of 19th century cholera epidemics of Victorian London).

Back to my area of the discussion and where I draw the line: I am most critical of some aspects of alternative medicine not because of whether they should be tested or not. Rather, I am critical of those who intentionally deceive patients and consumers with unproven therapies for their financial gain, personal fame, or both. I know a great many people whose income depends on the continued separation of alternative medicine from conventional medicine (kind of how the tag “alternative music” used to mean something). These people do not care for their modalities to be proven under conventional clinical trials because to do so would mean alienating themselves from their clients who wish to say they are doing something their doctors don’t know about/don’t believe in.

Hence, there should be no alternative medicine. There is medicine that has been proven, medicine that has not been proven, and modalities that are pure quackery meant only to enhance the revenue of the practitioners.


  1. #1 revere
    December 3, 2006

    Good post and it will be grist for my mill in the round-up of responses (so far two of them from the ScienceBlogger community). I still have some questions about what you say, however. Is the same herbal preparation alternative medicine and bullshit depending upon what explanation is given? That seems somewhat odd to me. I guess I’ll try to sort all of this out when I sit down to see the range of responses. Thanks for thinking about it.

  2. #2 Bill
    December 4, 2006

    Humility among scientists

    A rare and wonderful thing indeed.

  3. #3 Doc Bushwell
    December 4, 2006

    …my first question was whether the bioactive components of the soup get into the blood or mucosal tissue at the concentrations required to have such effects against isolated neutrophils. However, the bioactive component(s) were not identified in this work.

    I love it!

    “Pharmacokinetic and pharmcodynamic properties of Bubbie’s Chicken Soup.”

    “Identification of intact glucosinolates* in Grandma’s Chicken Soup by MALDI-TOF Mass Spectrometry.”

    *It’s the parsnips. It’s gotta be the parsnips.

  4. #4 Sandra Porter
    December 4, 2006

    Is the same herbal preparation alternative medicine and bullshit depending upon what explanation is given?

    My take is this:

    It’s not the preparation that’s medicine or “moo,”
    it’s the explanation that sounds sensible or “woo.”

  5. #5 deep6
    December 4, 2006

    Interesting read. You’ve given me something to think about.

  6. #6 Joe
    December 5, 2006

    Fascinating post! When someone suggested to me that the whole herb might contain a compound that potentiates the drug it contains, I responded that- by the same “reasoning” the herb might contain compounds that interfere with the drug, or are harmful in their own right. It’s like the calculation that you have a 50% of crossing the street safely because you’ll either get hit by a car or you won’t.

    When alties say scientists lack humility- where is their humility in providing evidence instead of mere “what if” arguments?

  7. #7 Abel Pharmboy
    December 5, 2006

    Doc B: Parsnips, eh?? I’m with ya: let’s rotovap that stuff and pass it over a silica column. Remind me to consult you for a title for our next paper.

    Revere: Doc Sandy Porter answered for me; in my book, an unfalsifiable explanation of a remedy renders it baloney. It may have biological activity even if the description is inconsistent with what we know about human physiology and cell biology. For example, those who are carefully working through traditional Chinese remedies are learning that many have biological activity even if we don’t have Western counterparts for qi or “drying herbs.” In fact, this mystery is what drew me to this research area: I feel that there are a lot of interesting pharmacological molecules in traditional medicines that have not yet been appreciated fully.

    Doc Hooker: Wisdom, indeed.

    Joe: Points well-taken, especially about the potential for interfering substances in whole herb preparations.

  8. #8 anonymous
    December 16, 2006

    I respect science to the utmost, and without foxglove and its derivative digoxin, I would not be alive today. One of the interesting things that happened to me recently was using tea tree oil to clean the skin/hair of a prepubescent daughter. OOPS!! I had no idea that it and lavender were biologically similar to estrogen… I have no idea if that is why she went through early puberty (defined by what is “normal” in the rest of our family ) but I suspect that is so. I found out by accident on the NYT a few months ago that this could happen with tea tree AND lavender. It went in the garbage immediately after I checked around a bit more on some medical sites. Why did I use tea tree oil? It was a “natural” alternative to some of the skin care products out there…. Now, not only are products checked for parabens and other icky things, but are checked for possible other effects if they are natural.

    As a parent I feel absolutely horrified that I possibly did this to my kid. I would NEVER EVER allow my kid to forgo traditional medical treatment in favour of “natural” alternatives, but I was rooked by something that I did not think to check out when it came to hygiene.

    And, as I am older, lavender and tea tree oil are off of my own routine.

    (In case you were wondering, tea tree oil first came into my house because I was worried about lice. I work with short kids in a tough area, and even with my hair back, I was always terrified by the possibility. )

    On a lighter note, when I told my family, my oldest daughter wondered aloud why I didn’t make the same mistake with her…. Gotta laugh or you are gonna cry, I guess….

  9. #9 David Harmon
    January 8, 2007

    Abel: Of course, someone may happen to be generally right about the effects or usefulness of their remedy, but still be ridiculously wrong about the reasons. Science is perfectly happy to take hints from non-scientific bodies of knowledge, such as local traditions. But for science and modern medicine, an observation “this stuff does such-and-such” is only a beginning. The claims need to be not merely tested properly, but investigated in detail — quantified, mechanisms traced, side-effects and interactions noted. Chicken soup in vitro is an extremely basic test in these terms!

    For Anonymous: Tea Tree Oil and the like may be particular aggravating factors, but in general, puberty is happening much earlier these days. There is much argument about the reasons; my own bet is on environmental pseudoestrogens in general (dioxin and other PCBs are famous examples). But yeah, this is a classic example of “natural isn’t always better”, especially if you don’t know enough about the stuff in question!