Quercetin Questions

September 24, 2010 1:50 PM

Beating colds: quercetin that combines high bioavailability and reasonable cost?

I first heard of quercetin here (or here if you prefer to read the original pdf, pages 9 & 10). My interest was piqued by the mention of indicating reductions of colds and viral infections. (Studies:1, 2, 3.)

The article says the studies used a "high purity quercetin called qu995," found only (afaik) in the relatively pricey FRS and Q-chews products. (The latter are reasonably priced, if I were in the military.)

Yet there are dozens of "generic" quercetin supplements in similar dosages for much less money per dose. But doubts about the efficacy compared to QU995 has me hesitating. I'm having trouble deciphering information on which formulations of are going to be absorbed well. (Quercetin + bromelain? Q3G? Q4G? Rutin? Eat with a burger? Or with red wine?)

What is my best bet for balancing efficacy and cost? I don't want to buy something that my body won't be able to use, but if I can buy something less expensive than FRS or Q-Chews, then I'm all about it. Can someone who is perhaps a bit savvier at interpreting PubMed jargon help guide me?

posted by BleachBypass to Health & Fitness (3 answers total)

Best answer: I would hazard the links to the burger and red wine are of minimal value because they deal with non-human trials. There may be some value to them, but few responsible people are going to advocate for something just based on that. Reading a bit about quercetin calls it somewhat into question because of the sheer number of claims it cures XYZ, and it is worth it to note it has not been approved by any regulatory agency, which means in part, that it will be pretty difficult to know for certain the level of purity or accuracy of claims on any product promoting it.

Some of the non human studies indicate pretty high levels of intake required. In a 150 pound human we're talking 900 - 1700 mg qd, and much of that (~95%) is actually flushed out within 72 hours . There are some contraindications for some antibiotics.

Generic vs. pro-brand? Given the uncertainty of effectiveness and the price, if you want to proceed I, personally, would go with the generic.

If flu and colds are your concern, I suspect the tried and true advice of washing your hands often, don't put your hands all over your face and getting a flu shot will go a long way towards avoidance.
posted by edgeways at 3:02 PM on September 24, 2010 [1 favorite]

Response by poster: So doing a bit more research, FRS et al uses quercetin aglycone; most of the supplements are quercetin dihydrate. The dihydrate appears to have less solubility... ahh, still don't fully understand it. Stupid chemistry.

Edgeways, those are some really good points about, ummm... in vivo humanis? Whatever it would be called. Though the absorption increase with meat study does mention using the pig because of strong similarities in the behavior of human and pig digestive tracts.

And trust me, I'll definitely still be washing hands and spitting on any owls crossing my path on a moonless night. And I already got my flu shot.
posted by BleachBypass at 11:03 PM on September 28, 2010

Response by poster: An aside - there are some compelling studies out there for quercetin. It's unfortunate that the marketing departments of supplement companies take any old study - in vitro, in vivo , instructive, inconclusive, who cares?!? - and spin it into XYZ cures.

(I guess one could say the same thing about vitamin C; claims to cure autism, colds, ADD and impotence in one fell swoop don't mean it's not damn good at preventing scurvy.)
posted by BleachBypass at 11:14 PM on September 28, 2010