“Baby, it’s cold denied” (Echinacea)


Most traditions this time of year are pleasant enough: Gift exchanges, The Nutcracker, eggnog. Alas, the late fall and winter months also bring an annual uptick in the common cold, although the weather only indirectly causes this. Lower temperatures don’t cause persons to catch cold, but it does prompt them to stay indoors, where they inhale stale air and spend more time next to family members, co-workers, and friends who may be housing a virus.

Meanwhile, a tradition that operates regardless of season is otherwise reputable media outlets pushing pseudoscience. The latest pitiful, predictable instance is Time boasting about Echinacea’s ability to tame the common cold. Like tales that push an even more implausible scenario of secret cancer cures, the story a herbaceous flowering plant’s cold-conquering powers confuses a multi-faceted concept with a single entity.

There are hundreds of cancer types and just as many viruses that are labeled the common cold.  It is not one illness, but scores of indistinguishable ones, each caused by a separate virus. They all impact the upper respiratory system and bring familiar maladies so they seem the same. But they are merely similar, meaning the idea of a catch-all cure is unrealistic.

In a tepid defense of the Time author, I should point out that he quoted self-described experts. This means he was accurately reporting what they said as opposed to just making up stuff himself and flinging it. Still, Time bears the ultimate responsibility for any medical misinformation appearing on its pages or website.

They should have done what Dr. Steven Novella did, which was to delve into published research on the matter. In so doing, Novella found a trio of studies, including two systemic reviews, that showed Echinacea to be of no value in speeding recovery from cold symptoms.

First, there was a 2010 study in the Annals of Internal Medicine which found cold-suffering subjects had the same results whether they received Echinacea, a placebo, or nothing. Then a 2014 review concluded that Echinacea users had no statistically significant benefit beyond what placebo poppers were experiencing. That same year, a Cochrane systemic review likewise showed that Echinacea was without benefit to cold treatment.

Despite these consistent underwhelming performances, Echinacea endures in part because proponents cherry pick and misrepresent lines in the reviews that suggest there may be some benefit. For example, the exhaustive Cochrane study contains the this sentence: “The results of individual prophylaxis trials consistently show positive (if non-significant) trends, although potential effects are of questionable clinical relevance.” Proponents pass this off as “consistent positivity,” even though the review as a whole made it clear that Echinacea has not shown to be effective at reducing cold effects. There are insignificant differences to some aspects and the review makes it clear that even that minor plus likely has no clinical relevance and is likely the result of statistical noise.

This refers to unexplained variation or randomness within a data sample. This noise is usually the result of error and this deviating data is unlikely to be replicated under the same, controlled conditions. In other words, Echinacea won’t take away your scratchy throat, make your eyes less watery, or reduce your cough’s intensity.

Proponents sometimes lean on the Appeals to Tradition and Nature Fallacies since the flowering plant was used as a sort of panacea by some 19th Century Native American tribes. Favoring anecdotes in lieu of data is another tactic. Or they cite a poorly-documented article in a media giant that should know better.

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