A scientist's review of the evidence for Kava's safety

[verticity]

Welcome to the Forum. This is a great write up!

Regarding this question:

Good thinking. This actually gets to a question I had about drinking that sediment. I've had some issues with stomach aches when drinking grog (I always mix before sipping to resuspend fine particles) and I was wondering if it had to do with root particles. Do you avoid drinking those on purpose, or do you just not bother to mix before drinking sometimes?

As a practical matter, I always use a filter bag rated at 80 microns or smaller. If I use a larger pore size I am likely to get stomach upset. But on the other hand, if you do use a good filter, the sediment is generally the "good" stuff, i.e. the most potent part. But this point also relates to your comments about water extraction of FKs:

I personally don’t want to mess with flavokavains, and they’re greatly enriched in organic extracts relative to water. Here’s a nice graph showing differences between water and ethanol extraction, from Martin et al, 2014. Note that organic extraction of flavokavain B is much higher than aqueous (bottom subfigure). Similarly, Zhou et al (2010) estimate that 95% ethanol and 100% acetone are ~160-times better at extracting flavokavain B than water. One thing that makes me somewhat reassured that flavokavain B isn’t very scary at typical rates of intake is the fact that that acute liver toxicity is a very rare issue, even with organic kava extracts. If typical organic extracts of kava had enough flavokavain B to cause acute liver injury, we’d expect to see it more often with those taking organic extracts....

This is something I have wondered about out loud before: in that paper, the method they use for water extraction is the following:

"Method I: 10 mL of room temperature water was added to 5 grams of powdered kava, shaken for 2 hrs, centrifuged to remove insoluble material and the supernatant evaporated to dryness and re-dissolved in water at a concentration of 1.5 mg of residue per mL."

But when you prepare kava the traditional way, there is a lot of sediment that gets through, and that sediment seems to be an important part of the beverage. If you centrifuge kava beverage, the result is a translucent brownish liquid with no psychoactive properties, because it contains very low levels of KLs. Basically it would just be a glutathione supplement at that point. So I'm really not sure if that kind of study is an accurate way to gauge the amount of FKs that you are drinking. The kava in the beverage is basically equivalent to rehydrated instant kava.

But having said all that, I do agree that traditional prep with water does have the best safety record, and also there is both in vitro and animal evidence that it really is safer.

 

[verticity]

One thing I’d love to hear from the community is whether acute hepatotoxic reactions continue to occur every year, or whether they occurred 20 years ago and haven’t occurred again since then. After all, hundreds of thousands of people take kava every day, and thus we can make a pretty powerful statistical inference from the long-term incidence rate (I mean, this is epidemiology 101). If contemporary hepatotoxic reactions are virtually nonexistent, then I think this provides pretty strong inferential evidence that the cases which occurred 20 years ago were caused by something other than kava itself (e.g., toxins other those naturally found in kava that got introduced into the supply chain through poor quality control).

When I look for "kava liver case reports" on Google Scholar, the great majority of the references are more than 10-15 years old. But I did find this recent article (Sept 2017):
Liver toxicity related to herbs and dietary supplements: Online table of case reports.
Based on the abstract I can't tell if this list actually exists somewhere, or if this is just announcing the intention to create the list. If you have access to the full text through your institution you might check out if it contains anything useful.
I found the full text and there is not much new stuff about kava...

 

[verticity]

From the article mentioned above A.C. Brown, Food and Chemical Toxicology 107 (2017) 472-501:
The author searched PubMed, and found the following case reports about kava:

The most recent reference, and the only one after 2003, is this:
Journal of Travel Medicine, Volume 16, Issue 1, 1 January 2009, Pages 55–56
This is a report about a tourist who was diagnosed with liver toxicity after drinking kava in ceremonies in Samoa over a 20 day period, but who later completely recovered. The article doesn't say when this happened, but the article was written in 2009.
Also: "He admitted alcohol consumption of not more than one drink daily but denied medication or drug use."

So, to answer your question, roughly 1 new case report in the past 15 years...

 

[Zac Imiola (Herbalist)]

1 new one with alcoholic beverage involved it seems.

 

[Edward]

Fair enough- sounds like it was a fun project though! I might try my hand at it for kicks.

I made instant using a food dehydrator. It works really well but as the captain says you get a very small amount in return for your effort. Also it's never going to be the same as commercial instant if you're starting with dried root. The beauty of a good instant is that it's the closest thing to fresh kava you can get in a dried product.

 

[Krunkie McKrunkface]

I made instant using a food dehydrator. It works really well but as the captain says you get a very small amount in return for your effort. Also it's never going to be the same as commercial instant if you're starting with dried root. The beauty of a good instant is that it's the closest thing to fresh kava you can get in a dried product.

Yeah, I don't know exactly what my homemade kava powder is. It's certainly not grog. It's more like the candies and the KWK concentrate. Still really nice, though, and just a fun thing to do. And it's something enjoyable that would otherwise go chucked.... good ROI. Probably not worth gearing production for it, better just the odd salvage project, an amusing hobby. I will say this, though, I save it in a pint jar and when a jar is full that smell is unbelievably nice. Very sweet. I could just sit there with that open jar under my nose for hours.

 

[kalmia_latifolia]

@kalmia_latifolia do you make wooden spoons?

I don't get the reference, but I do enjoy simple woodworking projects!

 

[kalmia_latifolia]

From the article mentioned above A.C. Brown, Food and Chemical Toxicology 107 (2017) 472-501:
The author searched PubMed, and found the following case reports about kava:

View attachment 8584

The most recent reference, and the only one after 2003, is this:
Journal of Travel Medicine, Volume 16, Issue 1, 1 January 2009, Pages 55–56
This is a report about a tourist who was diagnosed with liver toxicity after drinking kava in ceremonies in Samoa over a 20 day period, but who later completely recovered. The article doesn't say when this happened, but the article was written in 2009.
Also: "He admitted alcohol consumption of not more than one drink daily but denied medication or drug use."

So, to answer your question, roughly 1 new case report in the past 15 years...

Nice- that's a good find. Thanks for the digging!

 

[kalmia_latifolia]

I made instant using a food dehydrator. It works really well but as the captain says you get a very small amount in return for your effort. Also it's never going to be the same as commercial instant if you're starting with dried root. The beauty of a good instant is that it's the closest thing to fresh kava you can get in a dried product.

Funny- that's what I was going to try too. I'll probably give GHK's M'oi instant a try- I've been eying it a while. But I was also curious about making your own instant as a surrogate for micronized- just as easy, but with less potential for unexpected side-effects (dermo, FKB ingestion, etc.).

Edit- I just ordered 100g of the M'oi instant from GHK. Excited to try it!

 

[Zaphod]

There was this report in 2012 related to kidney function and Rhabdomyolysis....but the lack of data makes it hard to point directly at kava:
http://www.ajemjournal.com/article/S0735-6757(11)00061-1/pdf

 

[kalmia_latifolia]

There was this report in 2012 related to kidney function and Rhabdomyolysis....but the lack of data makes it hard to point directly at kava:
http://www.ajemjournal.com/article/S0735-6757(11)00061-1/pdf

That seems like a very bizarre reaction to get from a few kava tea bags...

 

[Zac Imiola (Herbalist)]

@kalmia_latifolia a quick google search of the plant name above showed that natives used it for wooden spoons.

What's your connection to this strange plant ?

 

[kalmia_latifolia]

@kalmia_latifolia a quick google search of the plant name above showed that natives used it for wooden spoons.

What's your connection to this strange plant ?

Hah, funny! Yeah, it's just a cool plant from the region where I live, and it had a name that reminded me of kava in the 'calming' sense. It was basically a really nerdy botanical pun.

 

[rapunzel]

Nice review of the liver tox situation. I have a phd in organic chemist and a lot of my work has been in pharmaceuticals. I had done a lot of looking at the scientific literature, though did not do the extensive analysis posted here!

I did come away from it thinking that the tox was either extremely rare, not directly related to kava or related to poor quality extracts. I tried a few extracts for a while, but I did worry about them. Some of them I think use either alcohol or SCCO2 as the solvent. These will absolutely result in a different profile of compounds in the extracts compared to H2O. It may not be a bad thing, but definitely different. So I stumbled on these forums and started trying some of the vendors here for the real kava and am very happy with the results!

 

[kalmia_latifolia]

Thanks @rapunzel- you have way more relevant expertise than I do (my PhD is in Ecology & Evolution)! How great do you think the differences in extraction between water and the stomach are (I'm thinking differences between traditional prep and micronized)?

 

[Dr.Krunk]

@kalmia_latifolia I’m late to the party on this but welcome! Absolutely appreciate your effort. There’s definitely a passionate community of Kava aficionados here, (some might refer to as crazy.) Any further insights into this wonderful plant: piper methisticum is always welcomed. Knowledge truly is the most powerful form of wealth that there is.

 

[rapunzel]

Don't give me too much credit. I know just enough to be a bit dangerous. Hadn't really thought about micro. I suppose we are taking in more of the actual root material than just a water extract, and then putting it in a very acidic environment, so that may alter things a bit. But I don't imagine that it would concentrate certain compounds the way ssco2 could. Totally speculating here though.

 

[Zac Imiola (Herbalist)]

Traditional islanders never strained their kava as well as we do today. As they didn't have fine enough filtering. They filter out the makas and that's it. The fine particles are meant to be in the drink. Some people are irritated by this though but it's a higher potency extraction in my opinion . Specifically I still extract my powders in water when I use them.. I don't rely on my stomach to do the work. So I'll put the powder in water and let it steep and extract then I'll drink all of it without straining... this increases bioavailability for obvious reasons.

 

[Zaphod]

There was also the possibility that they added synthetic kavain:
http://kavaforums.com/forum/threads...synthetic-kavain-and-not-actual-kavain.11082/

 

[verticity]

I had seen this article a while back, but realized it hadn't been linked here before. It's relevant to the question raised by the OP of this thread regarding recent case reports. The authors did a freedom of information request to find adverse event reports for kava from the FDA between 2004 and 2015. There were only 25 total adverse events reported, which included a handful of liver cases.
"Kava, with caveats: is this popular psychoactive tea bad for your liver?"

Important note: The fact that someone submitted an adverse event report to the FDA does not necessarily mean that the adverse event was caused by kava. These are simply anecdotes, and could well be related to other medications, existing medical conditions, etc. They do not establish causality. The fact that the total number of adverse events is pretty low is actually reassuring.