Kefir

Kefir/Drug Interactions:

  • AlcoholAlcohol: Kefir may contain up to 16g/L of ethanol on the second day of the fermentation process and up to 38g/L of ethanol after 7-10 days (11; 12).
  • AntibioticsAntibiotics: Theoretically, antibiotic drugs may damage some of the beneficial probiotic bacteria found in kefir.
  • AntifungalsAntifungals: Theoretically, antifungal drugs may damage some of the beneficial probiotic yeast found in kefir.
  • Disulfiram (Antabuse?)Disulfiram (Antabuse?): Kefir may contain ethanol that will interact with disulfiram (11; 12).
  • Metronidazole (Flagyl?)Metronidazole (Flagyl?): Kefir may contain ethanol and may elicit a disulfiram-like reaction (11; 12).

    • Kefir/Herb/Supplement Interactions:

  • AntibacterialsAntibacterials: Theoretically, antibiotic herbs and supplements may damage some of the beneficial probiotic bacteria found in kefir.
  • AntifungalsAntifungals: Theoretically, antifungal herbs and supplements may damage some of the beneficial probiotic yeast found in kefir.
  • B vitaminsB vitamins: Kefir provides a source of vitamin B12, B1, K, and biotin, which theoretically may aid the absorption of other B vitamins.
  • CalciumCalcium: In animal research, milk fermented with Lactobacillus helveticus has been shown to increase bone mineral content, which may be due to better calcium availability (4).
  • ProbioticsProbiotics: Theoretically, kefir contains live cultures of bacteria and yeast that may interfere with other probiotic supplements.

    • Kefir/Food Interactions:

  • Coprinopsis atramentariaCoprinopsis atramentaria: Kefir may contain ethanol (11; 12) and may elicit a disulfiram-like reaction, similar to that of the mushroom Coprinopsis atramentaria.

    • Kefir/Lab Interactions:

  • Breath hydrogenBreath hydrogen: The results from one study performed on human subjects showed that the breath hydrogen area under the curve for milk was significantly greater than plain yogurt, plain kefir, and flavored yogurt (10). Flavored kefir produced a lower response than milk, but higher than the other treatments.
  • Fecal analysisFecal analysis: The results from one study performed on human subjects showed that kefir and milk significantly increased fecal isobutyric, isovaleric, and propionic acids, as well as the total amount of fecal short-chain fatty acids (2). Kefir supplementation resulted in increased fecal bacteria content in the majority of the subjects.