Clinical Evidence

Effects of Turmeric and Curcumin Dietary Supplementation on Human Gut Microbiota: A Double-Blind, Randomized, Placebo-Controlled Pilot Study
 J Evid Based Integr Med. 2018; 23:1-8. DOI: 10.1177/2515690X18790725
Human gut microbiota is a collection of symbiotic microorganisms inhabiting the human intestine. These inhabiting symbiotic microbes play a vital role in nutrition, cognition, immunity and stress response of the host. Their impairment in number and type has been shown to affect the host pathology resulting in various diseases. Thus, managing the microbiota is very crucial in maintaining health. Various prebiotic components and phytoceuticals have been shown to improve the condition of gut microbiome. Curcuminoids have been shown to improve the gut microbiome in the preclinical studies. Insufficient data exist on the effects of curcumin and turmeric on the gut microbiota and such studies in humans are lacking

To evaluate the effect of curcumin and turmeric on the gut microbiota of healthy human subjects.


Turmeric tablets with extract of piperine (Bioperine®) (n = 6), curcumin with Bioperine® tablets (n = 5), or placebo tablets (n = 3) were provided to healthy human subjects and subsequent changes in the gut microbiota were determined by 16S rDNA sequencing.

  • The placebo group displayed an overall reduction in species by 15%, whereas turmeric-treated subjects displayed a modest 7% increase in observed species posttreatment. Subjects taking curcumin displayed an average increase of 69% in detected species
  • The gut microbiota response to treatment was highly personalized, thus leading to responders and nonresponders displaying response concordance
  • These “responsive” subjects defined a signature involving uniform increases in most Clostridium spp., Bacteroides spp., Citrobacter spp., Cronobacter spp., Enterobacter spp., Enterococcus spp., Klebsiella spp., Parabacteroides spp., and Pseudomonas spp. Common to these subjects was the reduced relative abundance of several Blautia spp. and most Ruminococcus spp

Among the responsive participants, both turmeric and curcumin altered the gut microbiota in a highly similar manner, suggesting that curcumin may drive the majority of observed changes observed in turmeric-treated subjects.