5 replies to this topic

[Dorian Grey]

Saw in this thread: 

 

http://www.longecity...ntsherbsspices/

 

"Quercetin,  damages DNA if post dose level is maintained too long from frequent repetition"

 

Googling around I found: https://www.ncbi.nlm...pubmed/10082921

 

Mechanism of oxidative DNA damage induced by quercetin in the presence of Cu(II).

 

"Quercetin, one of flavonoids, has been reported to be carcinogenic"  "Quercetin induced extensive DNA damage via reacting with Cu(II)"

 

Everything else I've seen on Quercetin (an ocean of positive data) indicates it is remarkably active against cancer.  Perhaps more is not better?  Is copper oxide (required for the adverse effect) present in normal cellular physiology?  

 

From what I've gathered, quercetin might be something you wouldn't want to dose more than once per day?  (frequent repetition)?  

 

I've also seen conflicting data on the half life of quercetin.  Anywhere from 3 hours, to over 24.  What's the consensus on risk/reward with supplemental Q?

 

Anyone have more info on this?  

Edited by Dorian Grey, 15 March 2018 - 06:02 AM.

[ta5]

It's also a Topoisomerase II inhibitor. 

Some other common supplements are too:

http://www.longecity...it-dna-enzymes/

[Dorian Grey]

Thanks for the links.  I'm still confused.  Should Quercetin by cycled?  Are minimal amounts found in food sources preferable to higher dose supplements? Are high doses found in supplements invariably dangerous?  

 

I'm a big believer in low doses and had to scour the internet to find the lowest dose Q possible.  Swanson has 250mg caps with 78mg bromelain.  I had read the body clears quercetin swiftly (half life 3 hours), so I take one cap 12 hours apart (2/day).  Last night I saw several sources stating terminal clearance for Q might be 24 hours or more. 

 

With so much positive information out there on Q, It's distressing to see something like this, but I'm having trouble wrapping my head around what the alarming studies are actually trying to say. 

 

In the second link, devinthayer indicates "If you are not taking anti-aging nucleic acid herbs like Ginkgo and Astragalus AND you are not nursing or pregnant, you will have nothing to worry about. They do not cause cancer at normal concentrations, just inhibit overgrowth or fast growth like in cancer cells". 

 

Is this the bottom line only for the small amounts found in food sources?  It appears even 250mg may be a very high dose compared to what is found in foods (typically less than 20mg).  Can anyone translate/elaborate? 

Edited by Dorian Grey, 15 March 2018 - 03:03 PM.

[REBUILDER]

"Concentrations of luteolin and quercetin that inhibited topo II catalytic activity resulted in extraordinarily high yields of metaphases showing diplochromosomes. Given the established relationship of polyploidy with tumor development via aneuploidy and genetic instability, these results question the usefulness of luteolin and quercetin in cancer therapy."

 

So high doses are probably one of the *last* things you want to take.

[Dorian Grey]

Thanks for this REB.  Guess I'll have to ditch the capsules and stick with my tea & onions for more moderate dietary Q.  

 

It's a shame you can't even buy a supplement with low doses that mimic a healthy diet.  Mega-Dosing madness is compromising the entire supplement industry.  

[Benko]

Are the "dangers" of quercetin above  just based on in vitro data?  or are there reasons to suspect it actually behaves this way in people?  e.g. the first link above uses "DNA fragments" and the topo link specifies "Chinese hamster cells"