Reactive Chemistry Blog

A physician friend asked me to look into the question of how to advise patients presenting with flu symptoms who had talked of taking alternative medicine supplements, such as echinacea. In the same breath he mentioned zinc supplements and selenium.

He wondered whether he should be advising his other patients to take one of these three supplements as a way of boosting the immune system ahead of the spread of a swine flu (H1N1) pandemic in order to stave off the worst symptoms.

The idea certainly presents a conundrum, not least because the benefits to the immune system of adding supplementary trace elements or herbal extracts to one’s diet is not proven either way in randomized, double-blind, placebo-controlled clinical trials.

My gut feeling is that one shouldn’t be advising anyone to take any supplements because of the potential for toxicity effects. Did you know that health problems have been seen in long-term users of echinacea, for instance, or that the presence of the toxic heavy cadmium is present in all zinc supplements? As for selenium, there is no evidence that anyone is ever deficient in this element because there is currently no way to determine how much we need or measure an individual’s body load.

However, if Zn, Se, or echinacea somehow do prime the immune system, then my doctor friend’s next concern was that should one catch swine flu, bird flu (H5N1) or some other influenza virus, that taking any of these supplements for too long could lead to the immune system running amok, causing a massive inflammatory response that is potentially lethal.

I asked another friend, an immunologist for her views.

My view would be that as the human immune system includes many checks and balances to prevent over-zealous immune responses, there should be little reason to think any of these supplements would make the immune system ‘run amok’ in response to swine flu.

She points out that the body will be employing all the mechanisms that it employs against other flu viruses to attempt to get rid of this particular one. So unless selenium etc are detrimental in immune responses against flu viruses generally (which I doubt), then I don’t see why taking the supplements should be a problem.

However, after I spoke to her I received a press release from the publisher of the journal Viral Immunology. The release discussed a paper on the so-called cytokine storm (my emphasis in bold):

The swine flu outbreak that began in Mexico and continues to spread around the globe may be particularly dangerous for young, otherwise healthy adults because it contains genetic components of avian influenza, which can induce a “cytokine storm,” in which a patient’s hyper-activated immune system causes potentially fatal damage to the lungs. Research studies and review articles exploring the regulation of cytokine responses in the lung and how infection-related dysregulation can cause a cytokine storm.

A cytokine storm occurs when the immune system overreacts to a virus, produces high levels of signaling molecules known as cytokines. These mobilize immune cells to kill the virus, but too many cytokines can cause significant inflammation and the accumulation of immune cells and fluid in organs, such as the lungs, which can kill the patient.

It was worry about this cytokine storm effect I believe my physician friend was alluding to in his question about whether patients should take immunostimulants before a pandemic. After all, if the immune system is actually stimulated by zinc, selenium, or echinacea, then it’s just possible that such alt meds could whip up a lethal cytokine storm even once the virus hits.

It was a cytokine storm that gave the 1918 Spanish flu epidemic its high mortality rate and underlies why bird flu can be so lethal. Thankfully, the current swine flu outbreak is not showing a propensity to kill in this way, but that is not to say that an evolved second wave outbreak might not do so.