For instance, when looking at the overall evidence, the analysis published in Nutrition & Diabetes reported no significant decrease in BMI post turmeric / curcumin supplementation.
However, when the evidence narrowed down to only high-absorption curcumin taken for at least 12 weeks, a significant reduction in BMI was seen.
A similar observation was seen when it comes to waist circumference and curcumin supplementation.
The meta-analysis was undertaken by a group of researchers based in Australia and Iran, including South Australian Health and Medical Research Institute and the Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute at Tehran University of Medical Sciences.
A total of 20 randomized controlled trials (RCTs) involving 1,387 adults - either prediabetic or diabetic - were included in the meta-analysis.
Across the 20 RCTs, the dose of turmeric/curcumin supplementation ranged from 80 mg/day to 2,100 mg/day, with the studies conducted for between eight and 36 weeks.
The types of curcumin used in the trial were also varied, including unformulated curcumin, high-absorption curcumin, and turmeric.
Findings showed that overall, turmeric/curcumin supplementation had significantly reduced parameters such as 1) body weight, 2) waist circumference, 3) fat mass, and 4) hip circumference but not 1) BMI and 2) waist-to-hip ratios in diabetic individuals.
Although no significant changes was seen in curcumin / turmeric supplementation and BMI, this was not the case if high-absorption curcumin was used.
Based on sub-group analysis, taking high-absorption curcumin for at least 12 weeks has shown to significantly reduced BMI in a sample size of over 60 people.
Similarly, dosage and duration of supplementation were observed to be key influencing factors, when it comes to improving waistline and body weight.
For instance, a significant reduction in waistline was seen at a dosage of over 1,500mg per day.
As for body weight, a significant reduction was seen when the supplementation was over 22 weeks.
“Our analysis revealed that turmeric/curcumin ultimately led to significant improvements in BW (body weight), WC (waist circumference), FM% (fat mass), and HC (hip circumference) among T2DM patients.
“However, association between turmeric/curcumin intake and BMI, WHR (waist-hip ratio) was not significant in these patients.
“In a non-linear dose-response fashion, a significant association between dosage of turmeric/curcumin with and WC and between duration of turmeric/curcumin consumption and BW was observed,” said the researchers.
They added that bioavailability of curcumin could be improved by using curcuminoids in the form of turmeric, instead of using pure curcumin.
Piperine can also enhance curcumin bioavailability, or incorporating curcumin into nanocarriers, or combining curcumin with phosphatidylcholine.
Findings in prediabetics
Among pre-diabetic individuals, the meta-analysis also found a significant reduction in body weight and waistline from curcumin / turmeric supplementation, as compared to placebos.
However, no significant changes were seen in BMI post-curcumin / turmeric supplementation.
In this case, the researchers did not state whether a greater dose or longer period of supplementation could have led to significant changes in BMI among pre-diabetics.
“The current systematic review and dose-response meta-analysis represent the first publication to assess the effects of turmeric/curcumin on anthropometric indices in individuals with prediabetes and T2DM.
“Our study had several strengths; First, we conducted a dose-response analysis to determine non-linear association between duration and dosage of supplementation with our outcomes.
“Second, we did not impose any language restrictions on the articles considered. Furthermore, our assessment of publication bias using Egger’s test did not reveal any significant bias among the included RCTs.
“Additionally, we establish subgroup analyses to find the source of heterogeneity,” the researchers concluded.
Source: Nutr. Diabetes 15, 34 (2025). DOI: 10.1038/s41387-025-00386-7. “The effect of turmeric/curcumin supplementation on anthropometric indices in subjects with prediabetes and type 2 diabetes mellitus: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials”, Authors: Moradi Baniasadi, M., Arzhang, P., Setayesh, A. et al.
