Does turmeric or curcumin have health benefits?
Turmeric probably helps treat several illnesses.
A 2017 meta-analysis of seven randomized controlled trials (RCTs) determined that turmeric and curcumin (the main chemical extracted from turmeric) were beneficial for reducing bad cholesterol and fat in the bloodstream among high-risk subjects. However, a 2014 meta-analysis of five RCTs found no clear evidence of impacts from unformulated curcumin on the general population.
A 2019 meta-analysis of eleven RCTs found that long-term turmeric or curcumin supplementation provided a small benefit to blood pressure, although these patients were not originally hypertensive anyway.
However, this research still has caveats. The differences among studies, including the variety in forms of turmeric and curcumin, make it difficult to draw conclusions. Additionally, most trials have been conducted in Asia, so they may not apply to people elsewhere. Finally, there is scant reason to expect curcumin to be beneficial, due to its low bioavailability and the misleading nature of positive lab results. But it is more plausible that improved formulations of curcumin, or turmeric itself, is beneficial; this might explain at least some of the positive RCT results.
There have been many other hypotheses about health benefits of turmeric or curcumin, but in general they have been unsupported or rejected by clinical trials.