Ah, Tudei kava. Perhaps no varietal of kava is getting more attention or press at the moment. Unfortunately a lot of it is currently bad press, as some distinguished kava researchers such as Vincent Lebot have come forward with recommendations against drinking kava made from Tudei varieties. I was frankly shocked at how quickly Tudei kava rose in notoriety as being somehow harmful, even though the science on why it might be so is still in its initial stages. I don’t think I was alone, either: many growers, retailers and connoisseurs in the kava community were blindsided by the emerging controversy surrounding Tudei kava strains. Over the past year I’ve seen two rough camps develop, divided between those who have sworn off Tudei kava and those who are still skeptical of the supposed evidence against Tudei kava. But before I can get into the controversy, I should probably break down a few things for our readers. Like what is Tudei kava?
What is Tudei Kava?
First of all, the term Tudei or Tuday kava doesn’t refer to just one strain, but actually a group of kava strains that are classified as “ignoble” according to Vanuatu’s kava export laws [1]. Tudei kava strains tend to have dark green stems and leaves, often with lighter green spots on the leaves. They also usually grow and mature quickly compared to other kava strains. Some people prize Tudei kava varieties for their perceived long-lasting effects-the effects can reportedly last as long as two days, hence the name-which are probably due to higher levels of large, slow-to-metabolize kavalactones such as dihydromethysticin in the kava root [2]. However, the longer-lasting effects can sometimes also be accompanied by undesirable side effects such as nausea and drowsiness [1], so the kava community is really split on whether the enjoyable parts of the Tudei experience outweigh the less pleasant aspects!
In Vanuatu, Tudei kava cultivars such as Isa and Palisi are actually banned from export by law (although one can still find them, or kava vendors claiming to sell them, online). This is because only “noble” kava cultivars with a specific chemotype are legal to export or process into kava supplement products. The explanation indigenous ni-Vanuatu people give for this is that Tudei or ignoble strains like Isa are reserved for ritual and medicinal use, and are considered too potent to be everyday drinking kavas [1]. There has even been a persistent rumor in some kava circles that Tudei kava is actually Piper wichmannii, the wild form of kava, and some vendors have exploited this hearsay to add an air of potency and exoticism to the the kava they sell. However, no genetic or morphological evidence has ever substantiated the claim that Tudei kava is P. wichmannii [2]. The Tudei strains may be chemically close to P. wichmannii in their ratios of kavalactones though, which could be where this claim originated.
The Emerging Tudei Kava Controversy:
I first became aware of the doubts surrounding Tudei kava from a post made on Kava Lounge by Andrew Procyk, owner of Vanuatu Kava Bar in Asheville, North Carolina and the recently opened Noble Kava Bar in Boone, North Carolina. He linked to a video featuring semi-famous kava luminary Vincent Lebot, in which Lebot recommends against drinking Tudei kava strains such as Isa and Palisi on the basis that they contain significant amounts of flavokavain B. His recommendation was based on data that suggest flavokavain B can be cytotoxic to human liver cells in lab tests [3].
Sigh. I thought the kava liver safety scares were over after the World Health Organization determined kava to be safe back in 2007 [4], but apparently not. The good news, though, is that Lebot and other kava researchers agree there is no detectable flavokavain B in the roots of noble kava cultivars [3]-those traditionally consumed nightly in the South Pacific as part of kastom-so even if flavokavain B turns out to be something to avoid, you don’t have to swear off noble kavas bought from scrupulous vendors. So, what’s the big deal with flavokavain B?
Flavokavains A, B, and C (also spelled flavokavins or flavokawains) are not kavalactones but are actually chalconoid compounds; precursors to the flavonoids found in many pigmented food plants like dark berries and dark orange or green vegetables [5]. Flavonoids have become darlings in the nutrition science world because research has shown that many of them provide significant health benefits like lowering inflammation in tissues and acting as antioxidants. The same can be said for other natural products such as marijuana, this has been noted as helping reduce internal inflammation, and people can get info at buymyweedonline.com if they want to research this further. Similarly, there is evidence the flavokavains in Tudei kava might be antifungal, antibacterial, and antioxidant [5]; Dr. Xiaolin Zhi at University of California Irvine has even discovered a tumor-preventive potential of flavokavain A in lab tests on mice [6]!
Seems good so far, doesn’t it? Unfortunately, the research also suggests there are two big problems specifically with flavokavain B. First, Dr. Chris Xing of the University of Minnesota has stated that flavokavain B may deplete glutathione, an antioxidant, liver-protective enzyme [7]. In a recent video interview featured on Natural Products Insider, Xing said, “[T]hat compromises liver function for detoxification… which may contribute to the observed hepatotoxicity among kava users”. As an antioxidant, glutathione plays a crucial role in scavenging free radicals produced by mitochondria (the organelles responsible for cellular respiration), and a severe enough deficit of glutathione can be fatal for cells [8]. A liver cannot work properly without working cells carrying out its functions, whether these are hepatocytes, endothelial cells, or kupffer cells, so anything that puts these under pressure or compromises them, is bad news for the body.
Even more troubling, this 2010 paper [9] found that flavokavain B also has direct toxic effects on two human liver cell lines: I’ll try not to get too technical, but the researchers found that adding flavokavain B to cultured liver cells inhibits a protein signaling pathway regulated by nuclear factor kappa B (NF-? B) that is involved in preventing cell death caused by tumor necrosis factor alpha (TNF-?). Under healthy conditions, these two signaling pathways balance each other, but when flavokavain B is added it knocks out the NF-? B pathway, leading to apoptosis (death) of the treated liver cells.
Two things about this study stood out to me. One was that the researchers experimented with altering different parts of this process and discovered that adding exogenous glutathione rescued the liver cells from flavokavain B-induced cell death, even when the process had already been set in motion in the treated cells [9]. I couldn’t help but be reminded of studies of kava I’ve come across stating that brews prepared using traditional cold water steeping were found to extract glutathione into the water along with the kavalactones [10]. The Kava Guru finds it hard to believe that these two pieces of data are a coincidence!
Final Verdict-Should You Avoid Tudei Kava?
Well… it’s complicated. The paper described above reports the mechanism of toxicity for flavokavain B extracted from kava kava root using an organic solvent. It’s important to remember that the amount of flavokavain B present in the extract used does not necessarily match the amount that would be found in a traditionally prepared aqueous kava brew, or a kava extract prepared using a modern solvent such as supercritical cold CO2. It’s well known that ethanol and acetone, two once-common solvents used to extract kava, extract everything in the root, not just the kavalactones, and that could include much higher levels of potentially harmful flavokavain B [8].
In fact, on page 5, table 1 of the paper, the researchers compare concentrations of flavokavain B in aqueous kava brews versus acetone- and ethanol-extracted kava extracts: kava extracts made with a 60% acetone extract contained 26 mg of flavokavain B per 1 gram of kava used, while a pure acetone extract contained 33.7 mg/g, and a 95% ethanol extract contained 32.3 mg/g [9]. How much flavokavain B did a traditional water-based Tudei kava brew contain? 0.2 mg/g [9]! What surprises me most about this outcome is that it suggests solvent-extracted kava extracts may actually have had a role in some of the liver toxicity cases of the early 2000s, a theory I thought had been debunked until now.
The very small amount of flavokavain B in an aqueous Tudei kava brew should, I think, at least give one pause before totally condemning Tudei kava as unsafe. Furthermore, in a co-op paper with Samuel X. Qiu and Rolf Teschke, Vincent Lebot explored three possible explanations for the idiosyncratic liver toxicity found in some kava users in the early 2000s [11]. One of those possible mechanisms was the presence of flavokavain B from Tudei kava, and the other two were the presence of pipermethystine from the aerial parts of kava, and possible contamination of kava roots with mold toxins (aflatoxins). In their results, the researchers noted that although both flavokavain B and pipermethystine have been shown to kill liver cells in lab tests, neither compound was detected in the commercial kava extracts tested at levels that would be of concern to human health [11]. They couldn’t detect pipermethystine at all in the extracts they tested. As for flavokavain B, even in the kava extracts where it was present, Lebot et al report that the concentration was much too low to cause harm in their experimental tests on liver cells. The conclusion of the paper states that contamination with mold aflatoxins due to poor storage conditions of the kava tested is actually the most likely explanation for the liver toxicity seen in 2002 and earlier cases [11].
Of course, no one should ignore that flavokavain B has been shown to have a detrimental effect on liver cells. But rather than state unequivocally that Tudei kavas are dangerous to consume, we have to look at all the factors in their preparation in order to make an informed choice about consuming them. A Tudei kava that has been solvent extracted and probably contains significant levels of flavokavain B might be wise to avoid. While Tudei kavas are consumed in the South Pacific, these cultures have traditionally only steeped the roots in water, and restricted them to occasional ceremonial and medicinal use rather than everyday drinking. It seems now that there is sound science behind the tradition.
REFERENCES
1. “Kava Definitions”. Kava Forums: Connecting Kava Lovers Around the World. Last modified May 30th, 2014. http://www.kavaforums.com/forum/wiki/kava-definitions/.
2. “Tudei Kava”. Kona Kava Farm. Accessed July 2nd, 2014. http://www.konakavafarm.com/kava-tudei.html.
3. Procyk, Andrew. “Drinking Tudei? Someone thinks you should probably stop.” The Kava Lounge: Science of Kava. Posted August 25th, 2013. http://kavalounge.yuku.com/topic/1576/Drinking-tudei-Someone-thinks-you-should-probably-stop#.U6iUeBZBm1A.
4. “WHO says Kava is Safe!” Kona Kava Farm Blog. Accessed July 2nd, 2014. http://www.konakavafarm.com/blog/kava-news/who-says-kava-is-safe/.
5. “Simple Test for Checking if your Kava is Tudei”. Kava Forums: Connecting Kava Lovers Around the World. Last modified May 26th, 2014. http://www.kavaforums.com/forum/threads/simple-test-for-checking-if-your-kava-is-tudei-please-read-if-youre-new-to-kava.2451/.
6. Vasich, Tom. “Can Kava Kava Cure Cancer?” UC Irvine News. Accessed June 29th, 2014. http://news.uci.edu/features/can-kava-cure-cancer/.
7. “New Science May Boost Kava Market” Insider TV: Natural Products Insider. Accessed July 2nd,2014. http://www.naturalproductsinsider.com/videos/2014/05/insider-tv-new-science-may-boost-kava-market.aspx.
8. “Dr. Xing: ‘Hepatotoxic Risk due to wrong cultivar […] and that Cultivar is Tudei Kava”. Kava Forums: Connecting Kava Lovers Around the World. Last modified May 28th, 2014. http://www.kavaforums.com/forum/threads/dr-xing-hepatotoxic-risk-due-to-wrong-cultivar-and-that-cultivar-is-tudei-kava.2557/.
9. Ping Zhou, Shimon Gross, Ji-Hua Liu, Bo-Yang Yu, Ling-Ling Feng, Jan Nolta, Vijay Sharma, David Piwnica-Worms, and Samuel X. Qiu. December 2010. “Flavokawain B, the hepatotoxic constituent from kava root, induces GSH-sensitive oxidative stress through modulation of IKK/NF-kB and MAPK signaling pathways”. Federation of American Societies for Experimental Biology Journal 24 (12): 4722-4732.
10. Whitton, PA, A Lau, A Salisbury, J Whitehouse, and CS Evans. October 2003. “Kavalactones and the kava kava controversy”. Phytochemistry 64 (3): 673-9.
11. Teschke, Rolf, Samuel X. Qiu, and Vincent Lebot. September 2011. “Herbal hepatotoxicity by kava: update on pipermethystine, flavokavain B, and mould hepatotoxins as primarily assumed culprits”. Digestive and Liver Disease 43 (9): 676-81.