The Kaptain (40g)
(Icey, Public domain, via Wikimedia Commons)
Recently we covered CYP450 enzymes and how kava may inhibit the activity at some of these areas. Today we’re going to focus specifically on the enzyme CYP1A2, and how inhibiting it effects caffeine metabolism.
We’ve seen quite a number of kava drinkers over the years remark about how their morning coffee began to be somewhat more of a stimulating experience. Some kava drinkers find this extra boost a side benefit of drinking kava. Other people experiencing this marked increase in stimulation may find it overpowering.
Caffeine metabolism occurs primarily in the liver, with a half-life of 5 hours, and requires about 8-10 hours to clear entirely. First pass metabolism accounts for 75-80% of caffeine’s metabolism in the body. The enzyme responsible for this is CYP1A2 .
Kava has been shown in its different forms to inhibit the enzyme CYP1A2 to varying degrees. In 2005 a study was carried out on kava drinking volunteers. They had the subjects stop drinking kava for 30 days, and measured the metabolic rate of caffeine both prior to and after the break. The caffeine metabolism ratio was shown to increase by 200% after 30 days. This indicated, when consuming kava on a regular basis, that some users can see what feels like DOUBLE the amount of caffeine they’ve ingested. This study also suggested these values return back to normal once kava drinking is stopped .
So, kava lovers, if you’ve been drinking your morning coffee and are seeing a definite increase in the stimulatory properties, this could be the culprit as to why.
 Institute of Medicine (US) Committee on Military Nutrition Research. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington (DC): National Academies Press (US); 2001. 2, Pharmacology of Caffeine. Available from: https://www.ncbi.nlm.nih.gov/books/NBK223808/
 Cabalion, P., Barguil, Y., Duhet, D., Mandeau, A., Warter, S., Russmann, S., Tarbah, F., & Daldrup, T. (2005). Kava in modern therapeutic uses: To a better evaluation of the benefit/risk relation: researches in New Caledonia and in Futuna. Revista de Fitoterapia, 5(special issue), 53–70.