Unlike much of the pseudo-medical interventions discussed at SfSBM and over at
Supplements? Who knows. Whether a given product will have efficacy can only be known through testing, even though the provenance of many supplements is suspect.
Take soy isoflavones, a group of phytoestrogens. Like many dietary products they are touted for a
Such a broad range of diseases with different pathophysiologies. Seems too good to be true. But that doesn’t mean the product doesn’t have effects on physiology and pathophysiology.
Except, as of today, asthma.
Among adults and children aged 12 years or older with poorly controlled asthma while taking a controller medication, use of a soy isoflavone supplement, compared with placebo, did not result in improved lung function or clinical outcomes. These findings suggest that this supplement should not be used for patients with poorly controlled asthma.
It was a large, multicenter, double blind, placebo controlled trial that followed 345 patients for 6 months. They received genistein, daidzein, and glycitein 100 mg or placebo.
It was not an implausible study, since early work suggested genistein inhibited eosinophile leukotriene C4 synthesis, important in asthma as well as some other potentially important metabolic pathways. There was also epidemiology to suggest soy isoflavone in the diet was associated with better lung function.
It was very well done. I was impressed that with 23 different p values reported, only one, exhaled nitrous oxide, had a significant p value. A sign, I suppose, of a well done negative study, as poorly powered studies often have noise that appears statistically significant.
The study was first registered at
How popular are soy isoflavones for asthma? I do not know. Neither the Natural News nor Mercola offer soy isoflavones for asthma and I can find little on the web. They are mostly offered for hot flashes from menopause, so it doesn’t appear to be have hit the pseudo-medical world as an asthma treatment.
Now, perhaps, it never will.