The study, published in late December in the journal Nutrients, was the work of a contract research organization and a university in Australia as well as an employee of Dolcas Biotech. Dolcas supplied its proprietary Curcugen turmeric extract for the study. Dolcas also supplied the funding.
The researchers recruited 101 subjects in Perth, Australia for the randomized, placebo-controlled study. Cohort of OA sufferers
The cohort included both men and women and ranged in age from 45 to 70. All participants had a diagnosis of knee osteoarthritis from a physician. The participants covered the gamut of body types, from very lean (BMI of 20) to moderately obese (BMI of 35). One of the inclusion criteria was a knee pain rating in the previous week of at least 6 on a 0-10 scale.
The participants took two capsules containing 500 mg of Curcugen or a placebo, divided among two daily doses, for eight weeks. Curcugen is described as a dispersible, 98.5% turmeric-based ingredient that contains 50% curcuminoids, 1.5% essential oils, and other native turmeric molecules, including turmeric polysaccharides.
Study measured outcomes via questionnaires, performance tests
The primary outcome was something called the Knee Injury and Osteoarthritis Outcome Score, or KOOS. This is described as “an extension of the WOMAC Osteoarthritis Index and is a validated self-report questionnaire designed to assess short and long-term patient-relevant outcomes associated with knee injury and pain.”
KOOS contains 42 scored items relating to knee pain, knee stiffness, function in daily life and effects when participating in sports. It also includes an overall quality of life score.
Secondary outcomes included the results of another knee assessment questionnaire from the Japanese Osteoarthritis Association (JOA) as well as performance testing. The performance tests included a sit-to-stand test, a get-up-and-go test, and 40 meter and a 6-minute walks around cones, both of which involved required frequent rapid changes of direction.
The researchers found that almost twice as many in the curcumin group achieved what the researchers referred to as a ‘minimal clinical important difference’ on the KOOS scale compared to the placebo group (33% versus 19%).
On the performance tests, the curcumin group showed statistically significant greater improvements in the chair tests and in the 6-minute walk test. No statistically relevant outcome was observed in the 40-meter walk test or in the 3-minute chair test, which assessed how many times participants could get up from a chair and sit back down within 3 minutes.
The researchers also assessed the effect of the Curcugen intervention on the use of pain medication by the subjects. About half of the participants in both groups reporting taking at least one NSAID dose for pain daily, so the number of subjects for this measurement was only about half the size of the overall study. At the end of the study, significantly more subjects taking Curcugen reported they had reduced their use of pain medication compared to placebo.
Measure used and nature of study material makes study unique
Dr Shavon Jackson-Michel, ND, director of Medical and Scientific Affairs for DolCas Biotech, said the measures used in the study set it apart from the main body of curcuminoids research.
“The point I find most interesting in this study is its evaluation of the Minimal Clinical Important Difference (MCID). It’s an outcome that’s considered to be meaningful for the subjects themselves and, as such, is both clinically important and elevates the results above simple statistical significance,” she said.
Jackson-Michel also said Curcugen’s unique profile means the results are specific to this particular ingredient.
“In contrast to certain generic curcumin products, Curcugen’s unique formulation preserves the original complex of curcuminoids, essential oils and polar resins within a natural matrix. These naturally occurring constituents synergistically increase curcumin bioavailability and, as supported by this trial, its efficacy in the treatment of OA of the knee,” she said.
2022, 14(1), 41; https://doi.org/10.3390/nu14010041
An Investigation into the Effects of a Curcumin Extract (Curcugen) on Osteoarthritis Pain of the Knee: A Randomised, Double-Blind, Placebo-Controlled Study
Authors: Lopresti AL, et al.